1gc1 - Revision history

OCA at 06:11, 9 August 2023

OCA — Wed, 09 Aug 2023 06:11:22 GMT

←Older revision		Revision as of 06:11, 9 August 2023
Line 3:		Line 3:
	<StructureSection load='1gc1' size='340' side='right'caption='[[1gc1]], [[Resolution\|resolution]] 2.50Å' scene=''>		<StructureSection load='1gc1' size='340' side='right'caption='[[1gc1]], [[Resolution\|resolution]] 2.50Å' scene=''>
	== Structural highlights ==		== Structural highlights ==
-	<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/~~9hiv1 9hiv1~~] and [https://en.wikipedia.org/wiki/Human ~~Human~~]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>	+	<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [https://en.wikipedia.org/wiki/Human_immunodeficiency_virus_1 Human immunodeficiency virus 1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>
-	</td></tr><tr id='~~ligand~~'><td class="sblockLbl"><b>[[~~Ligand~~\|~~Ligands~~:]]</b></td><td class="sblockDat" id="~~ligandDat~~">~~<scene name='pdbligand=NAG:N~~-~~ACETYL-D-GLUCOSAMINE'>NAG</scene>~~, ~~<scene name='pdbligand=FUC:ALPHA-L-FUCOSE'>FUC</scene>~~</td></tr>	+	</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models\|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution\|Resolution]] 2.5Å</td></tr>
-	<tr id='~~gene~~'><td class="sblockLbl"><b>[[~~Gene~~\|~~Gene~~:]]</b></td><td class="sblockDat">~~env ([https~~:/~~/www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode~~=~~Info&srchmode~~=~~5&id=11676 9HIV1])~~</td></tr>	+	<tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FUC:ALPHA-L-FUCOSE'>FUC</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene></td></tr>
	<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [https://pdbe.org/1gc1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [https://www.ebi.ac.uk/pdbsum/1gc1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1gc1 ProSAT]</span></td></tr>		<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [https://pdbe.org/1gc1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [https://www.ebi.ac.uk/pdbsum/1gc1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1gc1 ProSAT]</span></td></tr>
	</table>		</table>
	== Function ==		== Function ==
-	[[https://www.uniprot.org/uniprot/ENV_HV1H2 ENV_HV1H2]] The surface protein gp120 (SU) attaches the virus to the host lymphoid cell by binding to the primary receptor CD4. This interaction induces a structural rearrangement creating a high affinity binding site for a chemokine coreceptor like CXCR4 and/or CCR5. This peculiar 2 stage receptor-interaction strategy allows gp120 to maintain the highly conserved coreceptor-binding site in a cryptic conformation, protected from neutralizing antibodies. Since CD4 also displays a binding site for the disulfide-isomerase P4HB/PDI, a P4HB/PDI-CD4-CXCR4-gp120 complex may form. In that complex, P4HB/PDI could reach and reduce gp120 disulfide bonds, causing major conformational changes in gp120. TXN, another PDI family member could also be involved in disulfide rearrangements in Env during fusion. These changes are transmitted to the transmembrane protein gp41 and are thought to activate its fusogenic potential by unmasking its fusion peptide.<ref>PMID:19410541</ref> Surface protein gp120 (SU) may target the virus to gut-associated lymphoid tissue (GALT) by binding host ITGA4/ITGB7 (alpha-4/beta-7 integrins), a complex that mediates T-cell migration to the GALT. Interaction between gp120 and ITGA4/ITGB7 would allow the virus to enter GALT early in the infection, infecting and killing most of GALT's resting CD4+ T-cells. This T-cell depletion is believed to be the major insult to the host immune system leading to AIDS (By similarity).<ref>PMID:19410541</ref> The surface protein gp120 is a ligand for CD209/DC-SIGN and CLEC4M/DC-SIGNR, which are respectively found on dendritic cells (DCs), and on endothelial cells of liver sinusoids and lymph node sinuses. These interactions allow capture of viral particles at mucosal surfaces by these cells and subsequent transmission to permissive cells. DCs are professional antigen presenting cells, critical for host immunity by inducing specific immune responses against a broad variety of pathogens. They act as sentinels in various tissues where they take up antigen, process it, and present it to T-cells following migration to lymphoid organs. HIV subverts the migration properties of dendritic cells to gain access to CD4+ T-cells in lymph nodes. Virus transmission to permissive T-cells occurs either in trans (without DCs infection, through viral capture and transmission), or in cis (following DCs productive infection, through the usual CD4-gp120 interaction), thereby inducing a robust infection. In trans infection, bound virions remain infectious over days and it is proposed that they are not degraded, but protected in non-lysosomal acidic organelles within the DCs close to the cell membrane thus contributing to the viral infectious potential during DCs' migration from the periphery to the lymphoid tissues. On arrival at lymphoid tissues, intact virions recycle back to DCs' cell surface allowing virus transmission to CD4+ T-cells. Virion capture also seems to lead to MHC-II-restricted viral antigen presentation, and probably to the activation of HIV-specific CD4+ cells.<ref>PMID:19410541</ref> The transmembrane protein gp41 (TM) acts as a class I viral fusion protein. Under the current model, the protein has at least 3 conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During fusion of viral and target intracellular membranes, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes. Complete fusion occurs in host cell endosomes and is dynamin-dependent, however some lipid transfer might occur at the plasma membrane. The virus undergoes clathrin-dependent internalization long before endosomal fusion, thus minimizing the surface exposure of conserved viral epitopes during fusion and reducing the efficacy of inhibitors targeting these epitopes. Membranes fusion leads to delivery of the nucleocapsid into the cytoplasm.<ref>PMID:19410541</ref> The envelope glyprotein gp160 precursor down-modulates cell surface CD4 antigen by interacting with it in the endoplasmic reticulum and blocking its transport to the cell surface (By similarity).<ref>PMID:19410541</ref> The gp120-gp41 heterodimer seems to contribute to T-cell depletion during HIV-1 infection. The envelope glycoproteins expressed on the surface of infected cells induce apoptosis through an interaction with uninfected cells expressing the receptor (CD4) and the coreceptors CXCR4 or CCR5. This type of bystander killing may be obtained by at least three distinct mechanisms. First, the interaction between the 2 cells can induce cellular fusion followed by nuclear fusion within the syncytium. Syncytia are condemned to die from apoptosis. Second, the 2 interacting cells may not fuse entirely and simply exchange plasma membrane lipids, after a sort of hemifusion process, followed by rapid death. Third, it is possible that virus-infected cells, on the point of undergoing apoptosis, fuse with CD4-expressing cells, in which case apoptosis is rapidly transmitted from one cell to the other and thus occurs in a sort of contagious fashion.<ref>PMID:19410541</ref> The gp120-gp41 heterodimer allows rapid transcytosis of the virus through CD4 negative cells such as simple epithelial monolayers of the intestinal, rectal and endocervical epithelial barriers. Both gp120 and gp41 specifically recognize glycosphingolipids galactosyl-ceramide (GalCer) or 3' sulfo-galactosyl-ceramide (GalS) present in the lipid rafts structures of epithelial cells. Binding to these alternative receptors allows the rapid transcytosis of the virus through the epithelial cells. This transcytotic vesicle-mediated transport of virions from the apical side to the basolateral side of the epithelial cells does not involve infection of the cells themselves.<ref>PMID:19410541</ref> ~~[[https://www.uniprot.org/uniprot/CD4_HUMAN CD4_HUMAN]] Accessory protein for MHC class-II antigen/T-cell receptor interaction. May regulate T-cell activation. Induces the aggregation of lipid rafts.~~	+	[https://www.uniprot.org/uniprot/ENV_HV1H2 ENV_HV1H2] The surface protein gp120 (SU) attaches the virus to the host lymphoid cell by binding to the primary receptor CD4. This interaction induces a structural rearrangement creating a high affinity binding site for a chemokine coreceptor like CXCR4 and/or CCR5. This peculiar 2 stage receptor-interaction strategy allows gp120 to maintain the highly conserved coreceptor-binding site in a cryptic conformation, protected from neutralizing antibodies. Since CD4 also displays a binding site for the disulfide-isomerase P4HB/PDI, a P4HB/PDI-CD4-CXCR4-gp120 complex may form. In that complex, P4HB/PDI could reach and reduce gp120 disulfide bonds, causing major conformational changes in gp120. TXN, another PDI family member could also be involved in disulfide rearrangements in Env during fusion. These changes are transmitted to the transmembrane protein gp41 and are thought to activate its fusogenic potential by unmasking its fusion peptide.<ref>PMID:19410541</ref> Surface protein gp120 (SU) may target the virus to gut-associated lymphoid tissue (GALT) by binding host ITGA4/ITGB7 (alpha-4/beta-7 integrins), a complex that mediates T-cell migration to the GALT. Interaction between gp120 and ITGA4/ITGB7 would allow the virus to enter GALT early in the infection, infecting and killing most of GALT's resting CD4+ T-cells. This T-cell depletion is believed to be the major insult to the host immune system leading to AIDS (By similarity).<ref>PMID:19410541</ref> The surface protein gp120 is a ligand for CD209/DC-SIGN and CLEC4M/DC-SIGNR, which are respectively found on dendritic cells (DCs), and on endothelial cells of liver sinusoids and lymph node sinuses. These interactions allow capture of viral particles at mucosal surfaces by these cells and subsequent transmission to permissive cells. DCs are professional antigen presenting cells, critical for host immunity by inducing specific immune responses against a broad variety of pathogens. They act as sentinels in various tissues where they take up antigen, process it, and present it to T-cells following migration to lymphoid organs. HIV subverts the migration properties of dendritic cells to gain access to CD4+ T-cells in lymph nodes. Virus transmission to permissive T-cells occurs either in trans (without DCs infection, through viral capture and transmission), or in cis (following DCs productive infection, through the usual CD4-gp120 interaction), thereby inducing a robust infection. In trans infection, bound virions remain infectious over days and it is proposed that they are not degraded, but protected in non-lysosomal acidic organelles within the DCs close to the cell membrane thus contributing to the viral infectious potential during DCs' migration from the periphery to the lymphoid tissues. On arrival at lymphoid tissues, intact virions recycle back to DCs' cell surface allowing virus transmission to CD4+ T-cells. Virion capture also seems to lead to MHC-II-restricted viral antigen presentation, and probably to the activation of HIV-specific CD4+ cells.<ref>PMID:19410541</ref> The transmembrane protein gp41 (TM) acts as a class I viral fusion protein. Under the current model, the protein has at least 3 conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During fusion of viral and target intracellular membranes, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes. Complete fusion occurs in host cell endosomes and is dynamin-dependent, however some lipid transfer might occur at the plasma membrane. The virus undergoes clathrin-dependent internalization long before endosomal fusion, thus minimizing the surface exposure of conserved viral epitopes during fusion and reducing the efficacy of inhibitors targeting these epitopes. Membranes fusion leads to delivery of the nucleocapsid into the cytoplasm.<ref>PMID:19410541</ref> The envelope glyprotein gp160 precursor down-modulates cell surface CD4 antigen by interacting with it in the endoplasmic reticulum and blocking its transport to the cell surface (By similarity).<ref>PMID:19410541</ref> The gp120-gp41 heterodimer seems to contribute to T-cell depletion during HIV-1 infection. The envelope glycoproteins expressed on the surface of infected cells induce apoptosis through an interaction with uninfected cells expressing the receptor (CD4) and the coreceptors CXCR4 or CCR5. This type of bystander killing may be obtained by at least three distinct mechanisms. First, the interaction between the 2 cells can induce cellular fusion followed by nuclear fusion within the syncytium. Syncytia are condemned to die from apoptosis. Second, the 2 interacting cells may not fuse entirely and simply exchange plasma membrane lipids, after a sort of hemifusion process, followed by rapid death. Third, it is possible that virus-infected cells, on the point of undergoing apoptosis, fuse with CD4-expressing cells, in which case apoptosis is rapidly transmitted from one cell to the other and thus occurs in a sort of contagious fashion.<ref>PMID:19410541</ref> The gp120-gp41 heterodimer allows rapid transcytosis of the virus through CD4 negative cells such as simple epithelial monolayers of the intestinal, rectal and endocervical epithelial barriers. Both gp120 and gp41 specifically recognize glycosphingolipids galactosyl-ceramide (GalCer) or 3' sulfo-galactosyl-ceramide (GalS) present in the lipid rafts structures of epithelial cells. Binding to these alternative receptors allows the rapid transcytosis of the virus through the epithelial cells. This transcytotic vesicle-mediated transport of virions from the apical side to the basolateral side of the epithelial cells does not involve infection of the cells themselves.<ref>PMID:19410541</ref>
	== Evolutionary Conservation ==		== Evolutionary Conservation ==
	[[Image:Consurf_key_small.gif\|200px\|right]]		[[Image:Consurf_key_small.gif\|200px\|right]]
Line 39:		Line 39:
	__TOC__		__TOC__
	</StructureSection>		</StructureSection>
-	[[Category: Human]]	+	[[Category: Homo sapiens]]
		+	[[Category: Human immunodeficiency virus 1]]
	[[Category: Large Structures]]		[[Category: Large Structures]]
-	[[Category: Hendrickson~~, W A~~]]	+	[[Category: Hendrickson WA]]
-	[[Category: Kwong~~, P D~~]]	+	[[Category: Kwong PD]]
-	[[Category: Robinson, J]]	+	[[Category: Robinson J]]
-	[[Category: Sodroski, J]]	+	[[Category: Sodroski J]]
-	[[Category: Sweet~~, R W~~]]	+	[[Category: Sweet RW]]
-	[[Category: Wyatt, R]]	+	[[Category: Wyatt R]]
-	~~[[Category: Antigen-binding fragment of human immunoglobulin 17b]]~~	+
-	~~[[Category: Glycosylated protein]]~~	+
-	~~[[Category: Hiv-1 exterior envelope gp120]]~~	+
-	~~[[Category: T-cell surface glycoprotein cd4]]~~	+
-	~~[[Category: Viral protein-receptor-immune system complex~~]]	+

OCA at 09:50, 12 May 2021

OCA — Wed, 12 May 2021 09:50:31 GMT

←Older revision		Revision as of 09:50, 12 May 2021
Line 3:		Line 3:
	<StructureSection load='1gc1' size='340' side='right'caption='[[1gc1]], [[Resolution\|resolution]] 2.50Å' scene=''>		<StructureSection load='1gc1' size='340' side='right'caption='[[1gc1]], [[Resolution\|resolution]] 2.50Å' scene=''>
	== Structural highlights ==		== Structural highlights ==
-	<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [~~http~~://~~oca~~.~~weizmann.ac.il/oca-docs~~/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>	+	<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/9hiv1 9hiv1] and [https://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>
-	</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=~~FUC~~:~~ALPHA~~-L-~~FUCOSE~~'>~~FUC~~</scene>, <scene name='pdbligand=~~NAG~~:N-~~ACETYL~~-~~D-GLUCOSAMINE~~'>~~NAG~~</scene>, <~~scene name~~='~~pdbligand~~=~~NDG~~:~~2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE'~~>~~NDG~~</~~scene~~></td></tr>	+	</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=FUC:ALPHA-L-FUCOSE'>FUC</scene></td></tr>
-	<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[~~http~~://~~oca~~.~~weizmann.ac.il/oca-docs~~/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [~~http~~://pdbe.org/1gc1 PDBe], [~~http~~://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [~~http~~://www.ebi.ac.uk/pdbsum/1gc1 PDBsum], [~~http~~://prosat.h-its.org/prosat/prosatexe?pdbcode=1gc1 ProSAT]</span></td></tr>	+	<tr id='gene'><td class="sblockLbl"><b>[[Gene\|Gene:]]</b></td><td class="sblockDat">env ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=11676 9HIV1])</td></tr>
		+	<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [https://pdbe.org/1gc1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [https://www.ebi.ac.uk/pdbsum/1gc1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1gc1 ProSAT]</span></td></tr>
	</table>		</table>
	== Function ==		== Function ==
-	[[~~http~~://www.uniprot.org/uniprot/ENV_HV1H2 ENV_HV1H2]] The surface protein gp120 (SU) attaches the virus to the host lymphoid cell by binding to the primary receptor CD4. This interaction induces a structural rearrangement creating a high affinity binding site for a chemokine coreceptor like CXCR4 and/or CCR5. This peculiar 2 stage receptor-interaction strategy allows gp120 to maintain the highly conserved coreceptor-binding site in a cryptic conformation, protected from neutralizing antibodies. Since CD4 also displays a binding site for the disulfide-isomerase P4HB/PDI, a P4HB/PDI-CD4-CXCR4-gp120 complex may form. In that complex, P4HB/PDI could reach and reduce gp120 disulfide bonds, causing major conformational changes in gp120. TXN, another PDI family member could also be involved in disulfide rearrangements in Env during fusion. These changes are transmitted to the transmembrane protein gp41 and are thought to activate its fusogenic potential by unmasking its fusion peptide.<ref>PMID:19410541</ref> Surface protein gp120 (SU) may target the virus to gut-associated lymphoid tissue (GALT) by binding host ITGA4/ITGB7 (alpha-4/beta-7 integrins), a complex that mediates T-cell migration to the GALT. Interaction between gp120 and ITGA4/ITGB7 would allow the virus to enter GALT early in the infection, infecting and killing most of GALT's resting CD4+ T-cells. This T-cell depletion is believed to be the major insult to the host immune system leading to AIDS (By similarity).<ref>PMID:19410541</ref> The surface protein gp120 is a ligand for CD209/DC-SIGN and CLEC4M/DC-SIGNR, which are respectively found on dendritic cells (DCs), and on endothelial cells of liver sinusoids and lymph node sinuses. These interactions allow capture of viral particles at mucosal surfaces by these cells and subsequent transmission to permissive cells. DCs are professional antigen presenting cells, critical for host immunity by inducing specific immune responses against a broad variety of pathogens. They act as sentinels in various tissues where they take up antigen, process it, and present it to T-cells following migration to lymphoid organs. HIV subverts the migration properties of dendritic cells to gain access to CD4+ T-cells in lymph nodes. Virus transmission to permissive T-cells occurs either in trans (without DCs infection, through viral capture and transmission), or in cis (following DCs productive infection, through the usual CD4-gp120 interaction), thereby inducing a robust infection. In trans infection, bound virions remain infectious over days and it is proposed that they are not degraded, but protected in non-lysosomal acidic organelles within the DCs close to the cell membrane thus contributing to the viral infectious potential during DCs' migration from the periphery to the lymphoid tissues. On arrival at lymphoid tissues, intact virions recycle back to DCs' cell surface allowing virus transmission to CD4+ T-cells. Virion capture also seems to lead to MHC-II-restricted viral antigen presentation, and probably to the activation of HIV-specific CD4+ cells.<ref>PMID:19410541</ref> The transmembrane protein gp41 (TM) acts as a class I viral fusion protein. Under the current model, the protein has at least 3 conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During fusion of viral and target intracellular membranes, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes. Complete fusion occurs in host cell endosomes and is dynamin-dependent, however some lipid transfer might occur at the plasma membrane. The virus undergoes clathrin-dependent internalization long before endosomal fusion, thus minimizing the surface exposure of conserved viral epitopes during fusion and reducing the efficacy of inhibitors targeting these epitopes. Membranes fusion leads to delivery of the nucleocapsid into the cytoplasm.<ref>PMID:19410541</ref> The envelope glyprotein gp160 precursor down-modulates cell surface CD4 antigen by interacting with it in the endoplasmic reticulum and blocking its transport to the cell surface (By similarity).<ref>PMID:19410541</ref> The gp120-gp41 heterodimer seems to contribute to T-cell depletion during HIV-1 infection. The envelope glycoproteins expressed on the surface of infected cells induce apoptosis through an interaction with uninfected cells expressing the receptor (CD4) and the coreceptors CXCR4 or CCR5. This type of bystander killing may be obtained by at least three distinct mechanisms. First, the interaction between the 2 cells can induce cellular fusion followed by nuclear fusion within the syncytium. Syncytia are condemned to die from apoptosis. Second, the 2 interacting cells may not fuse entirely and simply exchange plasma membrane lipids, after a sort of hemifusion process, followed by rapid death. Third, it is possible that virus-infected cells, on the point of undergoing apoptosis, fuse with CD4-expressing cells, in which case apoptosis is rapidly transmitted from one cell to the other and thus occurs in a sort of contagious fashion.<ref>PMID:19410541</ref> The gp120-gp41 heterodimer allows rapid transcytosis of the virus through CD4 negative cells such as simple epithelial monolayers of the intestinal, rectal and endocervical epithelial barriers. Both gp120 and gp41 specifically recognize glycosphingolipids galactosyl-ceramide (GalCer) or 3' sulfo-galactosyl-ceramide (GalS) present in the lipid rafts structures of epithelial cells. Binding to these alternative receptors allows the rapid transcytosis of the virus through the epithelial cells. This transcytotic vesicle-mediated transport of virions from the apical side to the basolateral side of the epithelial cells does not involve infection of the cells themselves.<ref>PMID:19410541</ref> [[~~http~~://www.uniprot.org/uniprot/CD4_HUMAN CD4_HUMAN]] Accessory protein for MHC class-II antigen/T-cell receptor interaction. May regulate T-cell activation. Induces the aggregation of lipid rafts.	+	[[https://www.uniprot.org/uniprot/ENV_HV1H2 ENV_HV1H2]] The surface protein gp120 (SU) attaches the virus to the host lymphoid cell by binding to the primary receptor CD4. This interaction induces a structural rearrangement creating a high affinity binding site for a chemokine coreceptor like CXCR4 and/or CCR5. This peculiar 2 stage receptor-interaction strategy allows gp120 to maintain the highly conserved coreceptor-binding site in a cryptic conformation, protected from neutralizing antibodies. Since CD4 also displays a binding site for the disulfide-isomerase P4HB/PDI, a P4HB/PDI-CD4-CXCR4-gp120 complex may form. In that complex, P4HB/PDI could reach and reduce gp120 disulfide bonds, causing major conformational changes in gp120. TXN, another PDI family member could also be involved in disulfide rearrangements in Env during fusion. These changes are transmitted to the transmembrane protein gp41 and are thought to activate its fusogenic potential by unmasking its fusion peptide.<ref>PMID:19410541</ref> Surface protein gp120 (SU) may target the virus to gut-associated lymphoid tissue (GALT) by binding host ITGA4/ITGB7 (alpha-4/beta-7 integrins), a complex that mediates T-cell migration to the GALT. Interaction between gp120 and ITGA4/ITGB7 would allow the virus to enter GALT early in the infection, infecting and killing most of GALT's resting CD4+ T-cells. This T-cell depletion is believed to be the major insult to the host immune system leading to AIDS (By similarity).<ref>PMID:19410541</ref> The surface protein gp120 is a ligand for CD209/DC-SIGN and CLEC4M/DC-SIGNR, which are respectively found on dendritic cells (DCs), and on endothelial cells of liver sinusoids and lymph node sinuses. These interactions allow capture of viral particles at mucosal surfaces by these cells and subsequent transmission to permissive cells. DCs are professional antigen presenting cells, critical for host immunity by inducing specific immune responses against a broad variety of pathogens. They act as sentinels in various tissues where they take up antigen, process it, and present it to T-cells following migration to lymphoid organs. HIV subverts the migration properties of dendritic cells to gain access to CD4+ T-cells in lymph nodes. Virus transmission to permissive T-cells occurs either in trans (without DCs infection, through viral capture and transmission), or in cis (following DCs productive infection, through the usual CD4-gp120 interaction), thereby inducing a robust infection. In trans infection, bound virions remain infectious over days and it is proposed that they are not degraded, but protected in non-lysosomal acidic organelles within the DCs close to the cell membrane thus contributing to the viral infectious potential during DCs' migration from the periphery to the lymphoid tissues. On arrival at lymphoid tissues, intact virions recycle back to DCs' cell surface allowing virus transmission to CD4+ T-cells. Virion capture also seems to lead to MHC-II-restricted viral antigen presentation, and probably to the activation of HIV-specific CD4+ cells.<ref>PMID:19410541</ref> The transmembrane protein gp41 (TM) acts as a class I viral fusion protein. Under the current model, the protein has at least 3 conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During fusion of viral and target intracellular membranes, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes. Complete fusion occurs in host cell endosomes and is dynamin-dependent, however some lipid transfer might occur at the plasma membrane. The virus undergoes clathrin-dependent internalization long before endosomal fusion, thus minimizing the surface exposure of conserved viral epitopes during fusion and reducing the efficacy of inhibitors targeting these epitopes. Membranes fusion leads to delivery of the nucleocapsid into the cytoplasm.<ref>PMID:19410541</ref> The envelope glyprotein gp160 precursor down-modulates cell surface CD4 antigen by interacting with it in the endoplasmic reticulum and blocking its transport to the cell surface (By similarity).<ref>PMID:19410541</ref> The gp120-gp41 heterodimer seems to contribute to T-cell depletion during HIV-1 infection. The envelope glycoproteins expressed on the surface of infected cells induce apoptosis through an interaction with uninfected cells expressing the receptor (CD4) and the coreceptors CXCR4 or CCR5. This type of bystander killing may be obtained by at least three distinct mechanisms. First, the interaction between the 2 cells can induce cellular fusion followed by nuclear fusion within the syncytium. Syncytia are condemned to die from apoptosis. Second, the 2 interacting cells may not fuse entirely and simply exchange plasma membrane lipids, after a sort of hemifusion process, followed by rapid death. Third, it is possible that virus-infected cells, on the point of undergoing apoptosis, fuse with CD4-expressing cells, in which case apoptosis is rapidly transmitted from one cell to the other and thus occurs in a sort of contagious fashion.<ref>PMID:19410541</ref> The gp120-gp41 heterodimer allows rapid transcytosis of the virus through CD4 negative cells such as simple epithelial monolayers of the intestinal, rectal and endocervical epithelial barriers. Both gp120 and gp41 specifically recognize glycosphingolipids galactosyl-ceramide (GalCer) or 3' sulfo-galactosyl-ceramide (GalS) present in the lipid rafts structures of epithelial cells. Binding to these alternative receptors allows the rapid transcytosis of the virus through the epithelial cells. This transcytotic vesicle-mediated transport of virions from the apical side to the basolateral side of the epithelial cells does not involve infection of the cells themselves.<ref>PMID:19410541</ref> [[https://www.uniprot.org/uniprot/CD4_HUMAN CD4_HUMAN]] Accessory protein for MHC class-II antigen/T-cell receptor interaction. May regulate T-cell activation. Induces the aggregation of lipid rafts.
	== Evolutionary Conservation ==		== Evolutionary Conservation ==
	[[Image:Consurf_key_small.gif\|200px\|right]]		[[Image:Consurf_key_small.gif\|200px\|right]]
Line 33:		Line 34:
	*[[CD4 3D structures\|CD4 3D structures]]		*[[CD4 3D structures\|CD4 3D structures]]
	*[[Gp120 3D structures\|Gp120 3D structures]]		*[[Gp120 3D structures\|Gp120 3D structures]]
		+	*[[3D structures of human antibody\|3D structures of human antibody]]
	== References ==		== References ==
	<references/>		<references/>
	__TOC__		__TOC__
	</StructureSection>		</StructureSection>
		+	[[Category: Human]]
	[[Category: Large Structures]]		[[Category: Large Structures]]
	[[Category: Hendrickson, W A]]		[[Category: Hendrickson, W A]]

OCA at 06:53, 7 August 2019

OCA — Wed, 07 Aug 2019 06:53:58 GMT

←Older revision		Revision as of 06:53, 7 August 2019
Line 1:		Line 1:

	==HIV-1 GP120 CORE COMPLEXED WITH CD4 AND A NEUTRALIZING HUMAN ANTIBODY==		==HIV-1 GP120 CORE COMPLEXED WITH CD4 AND A NEUTRALIZING HUMAN ANTIBODY==
-	<StructureSection load='1gc1' size='340' side='right' caption='[[1gc1]], [[Resolution\|resolution]] 2.50Å' scene=''>	+	<StructureSection load='1gc1' size='340' side='right'caption='[[1gc1]], [[Resolution\|resolution]] 2.50Å' scene=''>
	== Structural highlights ==		== Structural highlights ==
	<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>		<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>
Line 13:		Line 13:
	Check<jmol>		Check<jmol>
	<jmolCheckbox>		<jmolCheckbox>
-	<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/gc/1gc1_consurf.spt"</scriptWhenChecked>	+	<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/gc/1gc1_consurf.spt"</scriptWhenChecked>
	<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>		<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
	<text>to colour the structure by Evolutionary Conservation</text>		<text>to colour the structure by Evolutionary Conservation</text>
Line 30:		Line 30:

	==See Also==		==See Also==
-	*[[CD4\|CD4]]	+	*[[Antibody 3D structures\|Antibody 3D structures]]
-	*[[3D structures ~~of antibody~~\|3D structures ~~of antibody~~]]	+	*[[CD4 3D structures\|CD4 3D structures]]
		+	*[[Gp120 3D structures\|Gp120 3D structures]]
	== References ==		== References ==
	<references/>		<references/>
	__TOC__		__TOC__
	</StructureSection>		</StructureSection>
		+	[[Category: Large Structures]]
	[[Category: Hendrickson, W A]]		[[Category: Hendrickson, W A]]
	[[Category: Kwong, P D]]		[[Category: Kwong, P D]]

OCA at 11:41, 6 November 2017

OCA — Mon, 06 Nov 2017 11:41:47 GMT

←Older revision		Revision as of 11:41, 6 November 2017
Line 31:		Line 31:
	==See Also==		==See Also==
	*[[CD4\|CD4]]		*[[CD4\|CD4]]
-	*[[Gp120\|Gp120]]
	*[[3D structures of antibody\|3D structures of antibody]]		*[[3D structures of antibody\|3D structures of antibody]]
	== References ==		== References ==

OCA at 10:48, 3 August 2017

OCA — Thu, 03 Aug 2017 10:48:51 GMT

←Older revision		Revision as of 10:48, 3 August 2017
Line 1:		Line 1:
		+
	==HIV-1 GP120 CORE COMPLEXED WITH CD4 AND A NEUTRALIZING HUMAN ANTIBODY==		==HIV-1 GP120 CORE COMPLEXED WITH CD4 AND A NEUTRALIZING HUMAN ANTIBODY==
	<StructureSection load='1gc1' size='340' side='right' caption='[[1gc1]], [[Resolution\|resolution]] 2.50Å' scene=''>		<StructureSection load='1gc1' size='340' side='right' caption='[[1gc1]], [[Resolution\|resolution]] 2.50Å' scene=''>
	== Structural highlights ==		== Structural highlights ==
-	<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure ~~with sequence from [http://en.wikipedia.org/wiki/9hiv1 9hiv1] and [http://en.wikipedia.org/wiki/Human Human]~~. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>	+	<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>
-	</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=~~NAG~~:N-~~ACETYL~~-~~D-GLUCOSAMINE~~'>~~NAG~~</scene>, <scene name='pdbligand=~~FUC~~:~~ALPHA~~-L-~~FUCOSE~~'>~~FUC~~</scene>, <scene name='pdbligand=NDG:2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE'>NDG</scene></td></tr>	+	</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=FUC:ALPHA-L-FUCOSE'>FUC</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=NDG:2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE'>NDG</scene></td></tr>
-	<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [http://pdbe.org/1gc1 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [http://www.ebi.ac.uk/pdbsum/1gc1 PDBsum]</span></td></tr>	+	<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [http://pdbe.org/1gc1 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [http://www.ebi.ac.uk/pdbsum/1gc1 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1gc1 ProSAT]</span></td></tr>
	</table>		</table>
	== Function ==		== Function ==
Line 29:		Line 30:

	==See Also==		==See Also==
-	*[[Antibody\|Antibody]]
	*[[CD4\|CD4]]		*[[CD4\|CD4]]
	*[[Gp120\|Gp120]]		*[[Gp120\|Gp120]]
		+	*[[3D structures of antibody\|3D structures of antibody]]
	== References ==		== References ==
	<references/>		<references/>
	__TOC__		__TOC__
	</StructureSection>		</StructureSection>
-	[[Category: Human]]
	[[Category: Hendrickson, W A]]		[[Category: Hendrickson, W A]]
	[[Category: Kwong, P D]]		[[Category: Kwong, P D]]

OCA at 00:40, 8 February 2016

OCA — Mon, 08 Feb 2016 00:40:52 GMT

←Older revision		Revision as of 00:40, 8 February 2016
Line 16:		Line 16:
	<text>to colour the structure by Evolutionary Conservation</text>		<text>to colour the structure by Evolutionary Conservation</text>
	</jmolCheckbox>		</jmolCheckbox>
-	</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary\|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/~~chain_selection~~.php?pdb_ID=~~2ata~~ ConSurf].	+	</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary\|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1gc1 ConSurf].
	<div style="clear:both"></div>		<div style="clear:both"></div>
	<div style="background-color:#fffaf0;">		<div style="background-color:#fffaf0;">

OCA at 06:17, 10 September 2015

OCA — Thu, 10 Sep 2015 06:17:51 GMT

←Older revision		Revision as of 06:17, 10 September 2015
Line 2:		Line 2:
	<StructureSection load='1gc1' size='340' side='right' caption='[[1gc1]], [[Resolution\|resolution]] 2.50Å' scene=''>		<StructureSection load='1gc1' size='340' side='right' caption='[[1gc1]], [[Resolution\|resolution]] 2.50Å' scene=''>
	== Structural highlights ==		== Structural highlights ==
-	<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/~~Homo_sapiens Homo sapiens~~] and [http://en.wikipedia.org/wiki/~~Human_immunodeficiency_virus_1~~ Human ~~immunodeficiency virus 1~~]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>	+	<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/9hiv1 9hiv1] and [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>
	</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=FUC:ALPHA-L-FUCOSE'>FUC</scene>, <scene name='pdbligand=NDG:2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE'>NDG</scene></td></tr>		</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=FUC:ALPHA-L-FUCOSE'>FUC</scene>, <scene name='pdbligand=NDG:2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE'>NDG</scene></td></tr>
-	<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [http://www.ebi.ac.uk/pdbsum/1gc1 PDBsum]</span></td></tr>	+	<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [http://pdbe.org/1gc1 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [http://www.ebi.ac.uk/pdbsum/1gc1 PDBsum]</span></td></tr>
	</table>		</table>
	== Function ==		== Function ==
Line 26:		Line 26:
	From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>		From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
	</div>		</div>
		+	<div class="pdbe-citations 1gc1" style="background-color:#fffaf0;"></div>

	==See Also==		==See Also==
Line 35:		Line 36:
	__TOC__		__TOC__
	</StructureSection>		</StructureSection>
-	~~[[Category: Homo sapiens]]~~	+	[[Category: Human]]
-	[[Category: Human ~~immunodeficiency virus 1~~]]	+
	[[Category: Hendrickson, W A]]		[[Category: Hendrickson, W A]]
	[[Category: Kwong, P D]]		[[Category: Kwong, P D]]

OCA at 19:19, 24 December 2014

OCA — Wed, 24 Dec 2014 19:19:06 GMT

←Older revision		Revision as of 19:19, 24 December 2014
Line 6:		Line 6:
	<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [http://www.ebi.ac.uk/pdbsum/1gc1 PDBsum]</span></td></tr>		<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [http://www.ebi.ac.uk/pdbsum/1gc1 PDBsum]</span></td></tr>
	</table>		</table>
		+	== Function ==
		+	[[http://www.uniprot.org/uniprot/ENV_HV1H2 ENV_HV1H2]] The surface protein gp120 (SU) attaches the virus to the host lymphoid cell by binding to the primary receptor CD4. This interaction induces a structural rearrangement creating a high affinity binding site for a chemokine coreceptor like CXCR4 and/or CCR5. This peculiar 2 stage receptor-interaction strategy allows gp120 to maintain the highly conserved coreceptor-binding site in a cryptic conformation, protected from neutralizing antibodies. Since CD4 also displays a binding site for the disulfide-isomerase P4HB/PDI, a P4HB/PDI-CD4-CXCR4-gp120 complex may form. In that complex, P4HB/PDI could reach and reduce gp120 disulfide bonds, causing major conformational changes in gp120. TXN, another PDI family member could also be involved in disulfide rearrangements in Env during fusion. These changes are transmitted to the transmembrane protein gp41 and are thought to activate its fusogenic potential by unmasking its fusion peptide.<ref>PMID:19410541</ref> Surface protein gp120 (SU) may target the virus to gut-associated lymphoid tissue (GALT) by binding host ITGA4/ITGB7 (alpha-4/beta-7 integrins), a complex that mediates T-cell migration to the GALT. Interaction between gp120 and ITGA4/ITGB7 would allow the virus to enter GALT early in the infection, infecting and killing most of GALT's resting CD4+ T-cells. This T-cell depletion is believed to be the major insult to the host immune system leading to AIDS (By similarity).<ref>PMID:19410541</ref> The surface protein gp120 is a ligand for CD209/DC-SIGN and CLEC4M/DC-SIGNR, which are respectively found on dendritic cells (DCs), and on endothelial cells of liver sinusoids and lymph node sinuses. These interactions allow capture of viral particles at mucosal surfaces by these cells and subsequent transmission to permissive cells. DCs are professional antigen presenting cells, critical for host immunity by inducing specific immune responses against a broad variety of pathogens. They act as sentinels in various tissues where they take up antigen, process it, and present it to T-cells following migration to lymphoid organs. HIV subverts the migration properties of dendritic cells to gain access to CD4+ T-cells in lymph nodes. Virus transmission to permissive T-cells occurs either in trans (without DCs infection, through viral capture and transmission), or in cis (following DCs productive infection, through the usual CD4-gp120 interaction), thereby inducing a robust infection. In trans infection, bound virions remain infectious over days and it is proposed that they are not degraded, but protected in non-lysosomal acidic organelles within the DCs close to the cell membrane thus contributing to the viral infectious potential during DCs' migration from the periphery to the lymphoid tissues. On arrival at lymphoid tissues, intact virions recycle back to DCs' cell surface allowing virus transmission to CD4+ T-cells. Virion capture also seems to lead to MHC-II-restricted viral antigen presentation, and probably to the activation of HIV-specific CD4+ cells.<ref>PMID:19410541</ref> The transmembrane protein gp41 (TM) acts as a class I viral fusion protein. Under the current model, the protein has at least 3 conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During fusion of viral and target intracellular membranes, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes. Complete fusion occurs in host cell endosomes and is dynamin-dependent, however some lipid transfer might occur at the plasma membrane. The virus undergoes clathrin-dependent internalization long before endosomal fusion, thus minimizing the surface exposure of conserved viral epitopes during fusion and reducing the efficacy of inhibitors targeting these epitopes. Membranes fusion leads to delivery of the nucleocapsid into the cytoplasm.<ref>PMID:19410541</ref> The envelope glyprotein gp160 precursor down-modulates cell surface CD4 antigen by interacting with it in the endoplasmic reticulum and blocking its transport to the cell surface (By similarity).<ref>PMID:19410541</ref> The gp120-gp41 heterodimer seems to contribute to T-cell depletion during HIV-1 infection. The envelope glycoproteins expressed on the surface of infected cells induce apoptosis through an interaction with uninfected cells expressing the receptor (CD4) and the coreceptors CXCR4 or CCR5. This type of bystander killing may be obtained by at least three distinct mechanisms. First, the interaction between the 2 cells can induce cellular fusion followed by nuclear fusion within the syncytium. Syncytia are condemned to die from apoptosis. Second, the 2 interacting cells may not fuse entirely and simply exchange plasma membrane lipids, after a sort of hemifusion process, followed by rapid death. Third, it is possible that virus-infected cells, on the point of undergoing apoptosis, fuse with CD4-expressing cells, in which case apoptosis is rapidly transmitted from one cell to the other and thus occurs in a sort of contagious fashion.<ref>PMID:19410541</ref> The gp120-gp41 heterodimer allows rapid transcytosis of the virus through CD4 negative cells such as simple epithelial monolayers of the intestinal, rectal and endocervical epithelial barriers. Both gp120 and gp41 specifically recognize glycosphingolipids galactosyl-ceramide (GalCer) or 3' sulfo-galactosyl-ceramide (GalS) present in the lipid rafts structures of epithelial cells. Binding to these alternative receptors allows the rapid transcytosis of the virus through the epithelial cells. This transcytotic vesicle-mediated transport of virions from the apical side to the basolateral side of the epithelial cells does not involve infection of the cells themselves.<ref>PMID:19410541</ref> [[http://www.uniprot.org/uniprot/CD4_HUMAN CD4_HUMAN]] Accessory protein for MHC class-II antigen/T-cell receptor interaction. May regulate T-cell activation. Induces the aggregation of lipid rafts.
	== Evolutionary Conservation ==		== Evolutionary Conservation ==
	[[Image:Consurf_key_small.gif\|200px\|right]]		[[Image:Consurf_key_small.gif\|200px\|right]]

OCA at 21:12, 22 December 2014

OCA — Mon, 22 Dec 2014 21:12:51 GMT

←Older revision		Revision as of 21:12, 22 December 2014
Line 3:		Line 3:
	== Structural highlights ==		== Structural highlights ==
	<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [http://en.wikipedia.org/wiki/Human_immunodeficiency_virus_1 Human immunodeficiency virus 1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>		<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [http://en.wikipedia.org/wiki/Human_immunodeficiency_virus_1 Human immunodeficiency virus 1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>
-	</td></tr><tr><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=FUC:ALPHA-L-FUCOSE'>FUC</scene>, <scene name='pdbligand=NDG:2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE'>NDG</scene><br>	+	</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=FUC:ALPHA-L-FUCOSE'>FUC</scene>, <scene name='pdbligand=NDG:2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE'>NDG</scene></td></tr>
-	<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [http://www.ebi.ac.uk/pdbsum/1gc1 PDBsum]</span></td></tr>	+	<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [http://www.ebi.ac.uk/pdbsum/1gc1 PDBsum]</span></td></tr>
-	<table>	+	</table>
	== Evolutionary Conservation ==		== Evolutionary Conservation ==
	[[Image:Consurf_key_small.gif\|200px\|right]]		[[Image:Consurf_key_small.gif\|200px\|right]]
Line 35:		Line 35:
	[[Category: Homo sapiens]]		[[Category: Homo sapiens]]
	[[Category: Human immunodeficiency virus 1]]		[[Category: Human immunodeficiency virus 1]]
-	[[Category: Hendrickson, W A.]]	+	[[Category: Hendrickson, W A]]
-	[[Category: Kwong, P D.]]	+	[[Category: Kwong, P D]]
-	[[Category: Robinson, J.]]	+	[[Category: Robinson, J]]
-	[[Category: Sodroski, J.]]	+	[[Category: Sodroski, J]]
-	[[Category: Sweet, R W.]]	+	[[Category: Sweet, R W]]
-	[[Category: Wyatt, R.]]	+	[[Category: Wyatt, R]]
	[[Category: Antigen-binding fragment of human immunoglobulin 17b]]		[[Category: Antigen-binding fragment of human immunoglobulin 17b]]
	[[Category: Glycosylated protein]]		[[Category: Glycosylated protein]]

OCA at 04:14, 3 October 2014

OCA — Fri, 03 Oct 2014 04:14:16 GMT

←Older revision		Revision as of 04:14, 3 October 2014
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-	~~{{STRUCTURE_1gc1\| PDB=1gc1 \| SCENE= }}~~	+	==HIV-1 GP120 CORE COMPLEXED WITH CD4 AND A NEUTRALIZING HUMAN ANTIBODY==
-	===HIV-1 GP120 CORE COMPLEXED WITH CD4 AND A NEUTRALIZING HUMAN ANTIBODY===	+	<StructureSection load='1gc1' size='340' side='right' caption='[[1gc1]], [[Resolution\|resolution]] 2.50Å' scene=''>
-	~~{{ABSTRACT_PUBMED_9641677}}~~	+	== Structural highlights ==
		+	<table><tr><td colspan='2'>[[1gc1]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [http://en.wikipedia.org/wiki/Human_immunodeficiency_virus_1 Human immunodeficiency virus 1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1GC1 FirstGlance]. <br>
		+	</td></tr><tr><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=FUC:ALPHA-L-FUCOSE'>FUC</scene>, <scene name='pdbligand=NDG:2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE'>NDG</scene><br>
		+	<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1gc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gc1 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1gc1 RCSB], [http://www.ebi.ac.uk/pdbsum/1gc1 PDBsum]</span></td></tr>
		+	<table>
		+	== Evolutionary Conservation ==
		+	[[Image:Consurf_key_small.gif\|200px\|right]]
		+	Check<jmol>
		+	<jmolCheckbox>
		+	<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/gc/1gc1_consurf.spt"</scriptWhenChecked>
		+	<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
		+	<text>to colour the structure by Evolutionary Conservation</text>
		+	</jmolCheckbox>
		+	</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary\|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf].
		+	<div style="clear:both"></div>
		+	<div style="background-color:#fffaf0;">
		+	== Publication Abstract from PubMed ==
		+	The entry of human immunodeficiency virus (HIV) into cells requires the sequential interaction of the viral exterior envelope glycoprotein, gp120, with the CD4 glycoprotein and a chemokine receptor on the cell surface. These interactions initiate a fusion of the viral and cellular membranes. Although gp120 can elicit virus-neutralizing antibodies, HIV eludes the immune system. We have solved the X-ray crystal structure at 2.5 A resolution of an HIV-1 gp120 core complexed with a two-domain fragment of human CD4 and an antigen-binding fragment of a neutralizing antibody that blocks chemokine-receptor binding. The structure reveals a cavity-laden CD4-gp120 interface, a conserved binding site for the chemokine receptor, evidence for a conformational change upon CD4 binding, the nature of a CD4-induced antibody epitope, and specific mechanisms for immune evasion. Our results provide a framework for understanding the complex biology of HIV entry into cells and should guide efforts to intervene.

-	~~==Function==~~	+	Structure of an HIV gp120 envelope glycoprotein in complex with the CD4 receptor and a neutralizing human antibody.,Kwong PD, Wyatt R, Robinson J, Sweet RW, Sodroski J, Hendrickson WA Nature. 1998 Jun 18;393(6686):648-59. PMID:9641677<ref>PMID:9641677</ref>
-	[[http://www.uniprot.org/uniprot/ENV_HV1H2 ENV_HV1H2]] The surface protein gp120 (SU) attaches the virus to the host lymphoid cell by binding to the primary receptor CD4. This interaction induces a structural rearrangement creating a high affinity binding site for a chemokine coreceptor like CXCR4 and/or CCR5. This peculiar 2 stage receptor-interaction strategy allows gp120 to maintain the highly conserved coreceptor-binding site in a cryptic conformation, protected from neutralizing antibodies. Since CD4 also displays a binding site for the disulfide-isomerase P4HB/PDI, a P4HB/PDI-CD4-CXCR4-gp120 complex may form. In that complex, P4HB/PDI could reach and reduce gp120 disulfide bonds, causing major conformational changes in gp120. TXN, another PDI family member could also be involved in disulfide rearrangements in Env during fusion. These changes are transmitted to the transmembrane protein gp41 and are thought to activate its fusogenic potential by unmasking its fusion peptide.<ref>PMID:19410541</ref> Surface protein gp120 (SU) may target the virus to gut-associated lymphoid tissue (GALT) by binding host ITGA4/ITGB7 (alpha-4/beta-7 integrins), a complex that mediates T-cell migration to the GALT. Interaction between gp120 and ITGA4/ITGB7 would allow the virus to enter GALT early in the infection, infecting and killing most of GALT's resting CD4+ T-cells. This T-cell depletion is believed to be the major insult to the host immune system leading to AIDS (By similarity).<ref>PMID:19410541</ref> The surface protein gp120 is a ligand for CD209/DC-SIGN and CLEC4M/DC-SIGNR, which are respectively found on dendritic cells (DCs), and on endothelial cells of liver sinusoids and lymph node sinuses. These interactions allow capture of viral particles at mucosal surfaces by these cells and subsequent transmission to permissive cells. DCs are professional antigen presenting cells, critical for host immunity by inducing specific immune responses against a broad variety of pathogens. They act as sentinels in various tissues where they take up antigen, process it, and present it to T-cells following migration to lymphoid organs. HIV subverts the migration properties of dendritic cells to gain access to CD4+ T-cells in lymph nodes. Virus transmission to permissive T-cells occurs either in trans (without DCs infection, through viral capture and transmission), or in cis (following DCs productive infection, through the usual CD4-gp120 ~~interaction), thereby inducing a robust infection. In trans infection, bound virions remain infectious over days and it is proposed that they are not degraded, but protected~~ in ~~non-lysosomal acidic organelles within~~ the DCs close to the cell membrane thus contributing to the viral infectious potential during DCs' migration from the periphery to the lymphoid tissues. On arrival at lymphoid tissues, intact virions recycle back to DCs' cell surface allowing virus transmission to CD4~~+ T-cells. Virion capture also seems to lead to MHC-II-restricted viral antigen presentation,~~ and ~~probably to the activation of HIV-specific CD4+ cells.<ref>PMID:19410541</ref> The transmembrane protein gp41 (TM) acts as~~ a ~~class I viral fusion protein~~. ~~Under the current model~~, ~~the protein has at least 3 conformational states: pre-fusion native state~~, ~~pre-hairpin intermediate state~~, ~~and post-fusion hairpin state. During fusion of viral and target intracellular membranes~~, ~~the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure~~, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes. Complete fusion occurs in host cell endosomes and is dynamin-dependent, ~~however some lipid transfer might occur at the plasma membrane~~. The virus undergoes clathrin-dependent internalization long before endosomal fusion, thus minimizing the surface exposure of conserved viral epitopes during fusion and reducing the efficacy of inhibitors targeting these epitopes. Membranes fusion leads to delivery of the nucleocapsid into the cytoplasm.<ref>PMID:19410541</ref> The envelope glyprotein gp160 precursor down-modulates cell surface CD4 antigen by interacting with it in the endoplasmic reticulum and blocking its transport to the cell surface (~~By similarity~~)~~.<ref>PMID~~:~~19410541</ref> The gp120~~-~~gp41 heterodimer seems to contribute to T-cell depletion during HIV-1 infection~~. The envelope glycoproteins expressed on the surface of infected cells induce apoptosis through an interaction with uninfected cells expressing the receptor (CD4) and the coreceptors CXCR4 or CCR5. This type of bystander killing may be obtained by at least three distinct mechanisms. First, the interaction between the 2 cells can induce cellular fusion followed by nuclear fusion within the syncytium. Syncytia are condemned to die from apoptosis. Second, the 2 interacting cells may not fuse entirely and simply exchange plasma membrane lipids, after a sort of hemifusion process, followed by rapid death. Third, it is possible that virus-infected cells, on the point of undergoing apoptosis, fuse with CD4-expressing cells, in which case apoptosis is rapidly transmitted from one cell to the other and thus occurs in a sort of contagious fashion.<ref>PMID:19410541</ref> The gp120-gp41 heterodimer allows rapid transcytosis of the virus through CD4 negative cells such as simple epithelial monolayers of the intestinal, rectal and endocervical epithelial barriers. Both gp120 and gp41 specifically recognize glycosphingolipids galactosyl-ceramide (GalCer) or 3' sulfo-galactosyl-ceramide (GalS) present in the lipid rafts structures of epithelial cells. Binding to these alternative receptors allows the rapid transcytosis of the virus through the epithelial cells. This transcytotic vesicle-mediated transport of virions from the apical side to the basolateral side of the epithelial cells does not involve infection of the cells themselves.<ref>PMID:~~19410541~~</ref> ~~[[http://www.uniprot.org/uniprot/CD4_HUMAN CD4_HUMAN]] Accessory protein for MHC class-II antigen/T-cell receptor interaction. May regulate T-cell activation. Induces the aggregation of lipid rafts.~~	+

-	~~==About this Structure==~~	+	From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
-	~~[[1gc1]] is~~ a ~~4 chain structure with sequence from [http://en~~.~~wikipedia~~.~~org/wiki/Homo_sapiens Homo sapiens] and [http://en~~.~~wikipedia.org~~/~~wiki/Human_immunodeficiency_virus_1 Human immunodeficiency virus 1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GC1 OCA].~~	+	</div>

	==See Also==		==See Also==
		+	*[[Antibody\|Antibody]]
	*[[CD4\|CD4]]		*[[CD4\|CD4]]
	*[[Gp120\|Gp120]]		*[[Gp120\|Gp120]]
-		+	== References ==
-	==~~Reference~~==	+	<references/>
-	~~<ref group="xtra">PMID:009641677</ref>~~<references ~~group="xtra"~~/><~~references~~/>	+	__TOC__
		+	</StructureSection>
	[[Category: Homo sapiens]]		[[Category: Homo sapiens]]
	[[Category: Human immunodeficiency virus 1]]		[[Category: Human immunodeficiency virus 1]]