1f7a - Revision history

OCA at 06:02, 9 August 2023

OCA — Wed, 09 Aug 2023 06:02:44 GMT

←Older revision		Revision as of 06:02, 9 August 2023
Line 3:		Line 3:
	<StructureSection load='1f7a' size='340' side='right'caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>		<StructureSection load='1f7a' size='340' side='right'caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>
	== Structural highlights ==		== Structural highlights ==
-	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/~~9hiv1 9hiv1~~]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F7A OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1F7A FirstGlance]. <br>	+	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/HIV-1_CRF04_cpx HIV-1 CRF04_cpx] 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=1F7A OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1F7A FirstGlance]. <br>
-	</td></tr><tr id='~~ligand~~'><td class="sblockLbl"><b>[[~~Ligand~~\|~~Ligands~~:]]</b></td><td class="sblockDat" id="~~ligandDat~~">~~<scene name='pdbligand=ACT:ACETATE+ION'>ACT</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]] 2Å</td></tr>
-	<tr id='~~activity~~'><td class="sblockLbl"><b>~~Activity~~:</b></td><td class="sblockDat"><~~span class~~='~~plainlinks~~'>~~[https://en.wikipedia.org/wiki/HIV-1_retropepsin HIV-1 retropepsin], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.16 3.4.23.16]~~ </~~span~~></td></tr>	+	<tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [https://pdbe.org/1f7a PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [https://www.ebi.ac.uk/pdbsum/1f7a PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1f7a 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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [https://pdbe.org/1f7a PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [https://www.ebi.ac.uk/pdbsum/1f7a PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1f7a ProSAT]</span></td></tr>
	</table>		</table>
	== Function ==		== Function ==
-	[[https://www.uniprot.org/uniprot/POL_HV1A2 POL_HV1A2]] Gag-Pol polyprotein and Gag polyprotein may regulate their own translation, by the binding genomic RNA in the 5'-UTR. At low concentration, Gag-Pol and Gag would promote translation, whereas at high concentration, the polyproteins encapsidate genomic RNA and then shutt off translation (By similarity). Matrix protein p17 has two main functions: in infected cell, it targets Gag and Gag-pol polyproteins to the plasma membrane via a multipartite membrane-binding signal, that includes its myristoylated N-terminus. The second function is to play a role in nuclear localization of the viral genome at the very start of cell infection. Matrix protein is the part of the pre-integration complex. It binds in the cytoplasm the human BAF protein which prevent autointegration of the viral genome, and might be included in virions at the ration of zero to 3 BAF dimer per virion. The myristoylation signal and the NLS thus exert conflicting influences its subcellular localization. The key regulation of these motifs might be phosphorylation of a portion of MA molecules on the C-terminal tyrosine at the time of virus maturation, by virion-associated cellular tyrosine kinase. Implicated in the release from host cell mediated by Vpu (By similarity). Capsid protein p24 forms the conical core that encapsulates the genomic RNA-nucleocapsid complex in the virion. Most core are conical, with only 7% tubular. The core is constituted by capsid protein hexamer subunits. The core is disassembled soon after virion entry. Interaction with human PPIA/CYPA protects the virus from restriction by human TRIM5-alpha and from an unknown antiviral activity in human cells. This capsid restriction by TRIM5 is one of the factors which restricts HIV-1 to the human species (By similarity). Nucleocapsid protein p7 encapsulates and protects viral dimeric unspliced (genomic) RNA. Binds these RNAs through its zinc fingers. Facilitates rearangement of nucleic acid secondary structure during retrotranscription of genomic RNA. This capability is referred to as nucleic acid chaperone activity (By similarity). The aspartyl protease mediates proteolytic cleavages of Gag and Gag-Pol polyproteins during or shortly after the release of the virion from the plasma membrane. Cleavages take place as an ordered, step-wise cascade to yield mature proteins. This process is called maturation. Displays maximal activity during the budding process just prior to particle release from the cell. Also cleaves Nef and Vif, probably concomitantly with viral structural proteins on maturation of virus particles (By similarity). Reverse transcriptase/ribonuclease H (RT) is a multifunctional enzyme that converts the viral RNA genome into dsDNA in the cytoplasm, shortly after virus entry into the cell. This enzyme displays a DNA polymerase activity that can copy either DNA or RNA templates, and a ribonuclease H (RNase H) activity that cleaves the RNA strand of RNA-DNA heteroduplexes in a partially processive 3' to 5' endonucleasic mode. Conversion of viral genomic RNA into dsDNA requires many steps. A tRNA(3)-Lys binds to the primer-binding site (PBS) situated at the 5'-end of the viral RNA. RT uses the 3' end of the tRNA primer to perform a short round of RNA-dependent minus-strand DNA synthesis. The reading proceeds through the U5 region and ends after the repeated (R) region which is present at both ends of viral RNA. The portion of the RNA-DNA heteroduplex is digested by the RNase H, resulting in a ssDNA product attached to the tRNA primer. This ssDNA/tRNA hybridizes with the identical R region situated at the 3' end of viral RNA. This template exchange, known as minus-strand DNA strong stop transfer, can be either intra- or intermolecular. RT uses the 3' end of this newly synthesized short ssDNA to perform the RNA-dependent minus-strand DNA synthesis of the whole template. RNase H digests the RNA template except for two polypurine tracts (PPTs) situated at the 5'-end and near the center of the genome. It is not clear if both polymerase and RNase H activities are simultaneous. RNase H probably can proceed both in a polymerase-dependent (RNA cut into small fragments by the same RT performing DNA synthesis) and a polymerase-independent mode (cleavage of remaining RNA fragments by free RTs). Secondly, RT performs DNA-directed plus-strand DNA synthesis using the PPTs that have not been removed by RNase H as primers. PPTs and tRNA primers are then removed by RNase H. The 3' and 5' ssDNA PBS regions hybridize to form a circular dsDNA intermediate. Strand displacement synthesis by RT to the PBS and PPT ends produces a blunt ended, linear dsDNA copy of the viral genome that includes long terminal repeats (LTRs) at both ends (By similarity). Integrase catalyzes viral DNA integration into the host chromosome, by performing a series of DNA cutting and joining reactions. This enzyme activity takes place after virion entry into a cell and reverse transcription of the RNA genome in dsDNA. The first step in the integration process is 3' processing. This step requires a complex comprising the viral genome, matrix protein, Vpr and integrase. This complex is called the pre-integration complex (PIC). The integrase protein removes 2 nucleotides from each 3' end of the viral DNA, leaving recessed CA OH's at the 3' ends. In the second step, the PIC enters cell nucleus. This process is mediated through integrase and Vpr proteins, and allows the virus to infect a non dividing cell. This ability to enter the nucleus is specific of lentiviruses, other retroviruses cannot and rely on cell division to access cell chromosomes. In the third step, termed strand transfer, the integrase protein joins the previously processed 3' ends to the 5' ends of strands of target cellular DNA at the site of integration. The 5'-ends are produced by integrase-catalyzed staggered cuts, 5 bp apart. A Y-shaped, gapped, recombination intermediate results, with the 5'-ends of the viral DNA strands and the 3' ends of target DNA strands remaining unjoined, flanking a gap of 5 bp. The last step is viral DNA integration into host chromosome. This involves host DNA repair synthesis in which the 5 bp gaps between the unjoined strands are filled in and then ligated. Since this process occurs at both cuts flanking the HIV genome, a 5 bp duplication of host DNA is produced at the ends of HIV-1 integration. Alternatively, Integrase may catalyze the excision of viral DNA just after strand transfer, this is termed disintegration (By similarity).	+	[https://www.uniprot.org/uniprot/POL_HV1A2 POL_HV1A2] Gag-Pol polyprotein and Gag polyprotein may regulate their own translation, by the binding genomic RNA in the 5'-UTR. At low concentration, Gag-Pol and Gag would promote translation, whereas at high concentration, the polyproteins encapsidate genomic RNA and then shutt off translation (By similarity). Matrix protein p17 has two main functions: in infected cell, it targets Gag and Gag-pol polyproteins to the plasma membrane via a multipartite membrane-binding signal, that includes its myristoylated N-terminus. The second function is to play a role in nuclear localization of the viral genome at the very start of cell infection. Matrix protein is the part of the pre-integration complex. It binds in the cytoplasm the human BAF protein which prevent autointegration of the viral genome, and might be included in virions at the ration of zero to 3 BAF dimer per virion. The myristoylation signal and the NLS thus exert conflicting influences its subcellular localization. The key regulation of these motifs might be phosphorylation of a portion of MA molecules on the C-terminal tyrosine at the time of virus maturation, by virion-associated cellular tyrosine kinase. Implicated in the release from host cell mediated by Vpu (By similarity). Capsid protein p24 forms the conical core that encapsulates the genomic RNA-nucleocapsid complex in the virion. Most core are conical, with only 7% tubular. The core is constituted by capsid protein hexamer subunits. The core is disassembled soon after virion entry. Interaction with human PPIA/CYPA protects the virus from restriction by human TRIM5-alpha and from an unknown antiviral activity in human cells. This capsid restriction by TRIM5 is one of the factors which restricts HIV-1 to the human species (By similarity). Nucleocapsid protein p7 encapsulates and protects viral dimeric unspliced (genomic) RNA. Binds these RNAs through its zinc fingers. Facilitates rearangement of nucleic acid secondary structure during retrotranscription of genomic RNA. This capability is referred to as nucleic acid chaperone activity (By similarity). The aspartyl protease mediates proteolytic cleavages of Gag and Gag-Pol polyproteins during or shortly after the release of the virion from the plasma membrane. Cleavages take place as an ordered, step-wise cascade to yield mature proteins. This process is called maturation. Displays maximal activity during the budding process just prior to particle release from the cell. Also cleaves Nef and Vif, probably concomitantly with viral structural proteins on maturation of virus particles (By similarity). Reverse transcriptase/ribonuclease H (RT) is a multifunctional enzyme that converts the viral RNA genome into dsDNA in the cytoplasm, shortly after virus entry into the cell. This enzyme displays a DNA polymerase activity that can copy either DNA or RNA templates, and a ribonuclease H (RNase H) activity that cleaves the RNA strand of RNA-DNA heteroduplexes in a partially processive 3' to 5' endonucleasic mode. Conversion of viral genomic RNA into dsDNA requires many steps. A tRNA(3)-Lys binds to the primer-binding site (PBS) situated at the 5'-end of the viral RNA. RT uses the 3' end of the tRNA primer to perform a short round of RNA-dependent minus-strand DNA synthesis. The reading proceeds through the U5 region and ends after the repeated (R) region which is present at both ends of viral RNA. The portion of the RNA-DNA heteroduplex is digested by the RNase H, resulting in a ssDNA product attached to the tRNA primer. This ssDNA/tRNA hybridizes with the identical R region situated at the 3' end of viral RNA. This template exchange, known as minus-strand DNA strong stop transfer, can be either intra- or intermolecular. RT uses the 3' end of this newly synthesized short ssDNA to perform the RNA-dependent minus-strand DNA synthesis of the whole template. RNase H digests the RNA template except for two polypurine tracts (PPTs) situated at the 5'-end and near the center of the genome. It is not clear if both polymerase and RNase H activities are simultaneous. RNase H probably can proceed both in a polymerase-dependent (RNA cut into small fragments by the same RT performing DNA synthesis) and a polymerase-independent mode (cleavage of remaining RNA fragments by free RTs). Secondly, RT performs DNA-directed plus-strand DNA synthesis using the PPTs that have not been removed by RNase H as primers. PPTs and tRNA primers are then removed by RNase H. The 3' and 5' ssDNA PBS regions hybridize to form a circular dsDNA intermediate. Strand displacement synthesis by RT to the PBS and PPT ends produces a blunt ended, linear dsDNA copy of the viral genome that includes long terminal repeats (LTRs) at both ends (By similarity). Integrase catalyzes viral DNA integration into the host chromosome, by performing a series of DNA cutting and joining reactions. This enzyme activity takes place after virion entry into a cell and reverse transcription of the RNA genome in dsDNA. The first step in the integration process is 3' processing. This step requires a complex comprising the viral genome, matrix protein, Vpr and integrase. This complex is called the pre-integration complex (PIC). The integrase protein removes 2 nucleotides from each 3' end of the viral DNA, leaving recessed CA OH's at the 3' ends. In the second step, the PIC enters cell nucleus. This process is mediated through integrase and Vpr proteins, and allows the virus to infect a non dividing cell. This ability to enter the nucleus is specific of lentiviruses, other retroviruses cannot and rely on cell division to access cell chromosomes. In the third step, termed strand transfer, the integrase protein joins the previously processed 3' ends to the 5' ends of strands of target cellular DNA at the site of integration. The 5'-ends are produced by integrase-catalyzed staggered cuts, 5 bp apart. A Y-shaped, gapped, recombination intermediate results, with the 5'-ends of the viral DNA strands and the 3' ends of target DNA strands remaining unjoined, flanking a gap of 5 bp. The last step is viral DNA integration into host chromosome. This involves host DNA repair synthesis in which the 5 bp gaps between the unjoined strands are filled in and then ligated. Since this process occurs at both cuts flanking the HIV genome, a 5 bp duplication of host DNA is produced at the ends of HIV-1 integration. Alternatively, Integrase may catalyze the excision of viral DNA just after strand transfer, this is termed disintegration (By similarity).
	== Evolutionary Conservation ==		== Evolutionary Conservation ==
	[[Image:Consurf_key_small.gif\|200px\|right]]		[[Image:Consurf_key_small.gif\|200px\|right]]
Line 36:		Line 36:
	__TOC__		__TOC__
	</StructureSection>		</StructureSection>
-	[[Category: HIV-1 ~~retropepsin~~]]	+	[[Category: HIV-1 CRF04_cpx]]
		+	[[Category: Human immunodeficiency virus 1]]
	[[Category: Large Structures]]		[[Category: Large Structures]]
-	[[Category: Schiffer~~, C A]]~~	+	[[Category: Schiffer CA]]
-	~~[[Category: Capsid]]~~	+
-	~~[[Category: Hydrolase]]~~	+
-	~~[[Category: Substrate recognition~~]]	+

OCA at 15:10, 3 November 2021

OCA — Wed, 03 Nov 2021 15:10:12 GMT

←Older revision		Revision as of 15:10, 3 November 2021
Line 3:		Line 3:
	<StructureSection load='1f7a' size='340' side='right'caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>		<StructureSection load='1f7a' size='340' side='right'caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>
	== Structural highlights ==		== Structural highlights ==
-	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F7A OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1F7A FirstGlance]. <br>	+	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/9hiv1 9hiv1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F7A OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1F7A FirstGlance]. <br>
	</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene></td></tr>		</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene></td></tr>
	<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/HIV-1_retropepsin HIV-1 retropepsin], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.16 3.4.23.16] </span></td></tr>		<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/HIV-1_retropepsin HIV-1 retropepsin], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.16 3.4.23.16] </span></td></tr>

OCA at 07:20, 17 March 2021

OCA — Wed, 17 Mar 2021 07:20:10 GMT

←Older revision		Revision as of 07:20, 17 March 2021
Line 3:		Line 3:
	<StructureSection load='1f7a' size='340' side='right'caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>		<StructureSection load='1f7a' size='340' side='right'caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>
	== Structural highlights ==		== Structural highlights ==
-	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F7A OCA]. For a <b>guided tour on the structure components</b> use [~~http~~://~~oca~~.~~weizmann.ac.il/oca-docs~~/fgij/fg.htm?mol=1F7A FirstGlance]. <br>	+	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F7A OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1F7A FirstGlance]. <br>
-	</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene></td></tr>	+	</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene></td></tr>
-	<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[~~http~~://en.wikipedia.org/wiki/HIV-1_retropepsin HIV-1 retropepsin], with EC number [~~http~~://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.16 3.4.23.16] </span></td></tr>	+	<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/HIV-1_retropepsin HIV-1 retropepsin], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.16 3.4.23.16] </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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [~~http~~://pdbe.org/1f7a PDBe], [~~http~~://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [~~http~~://www.ebi.ac.uk/pdbsum/1f7a PDBsum], [~~http~~://prosat.h-its.org/prosat/prosatexe?pdbcode=1f7a 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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [https://pdbe.org/1f7a PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [https://www.ebi.ac.uk/pdbsum/1f7a PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1f7a ProSAT]</span></td></tr>
	</table>		</table>
	== Function ==		== Function ==
-	[[~~http~~://www.uniprot.org/uniprot/POL_HV1A2 POL_HV1A2]] Gag-Pol polyprotein and Gag polyprotein may regulate their own translation, by the binding genomic RNA in the 5'-UTR. At low concentration, Gag-Pol and Gag would promote translation, whereas at high concentration, the polyproteins encapsidate genomic RNA and then shutt off translation (By similarity). Matrix protein p17 has two main functions: in infected cell, it targets Gag and Gag-pol polyproteins to the plasma membrane via a multipartite membrane-binding signal, that includes its myristoylated N-terminus. The second function is to play a role in nuclear localization of the viral genome at the very start of cell infection. Matrix protein is the part of the pre-integration complex. It binds in the cytoplasm the human BAF protein which prevent autointegration of the viral genome, and might be included in virions at the ration of zero to 3 BAF dimer per virion. The myristoylation signal and the NLS thus exert conflicting influences its subcellular localization. The key regulation of these motifs might be phosphorylation of a portion of MA molecules on the C-terminal tyrosine at the time of virus maturation, by virion-associated cellular tyrosine kinase. Implicated in the release from host cell mediated by Vpu (By similarity). Capsid protein p24 forms the conical core that encapsulates the genomic RNA-nucleocapsid complex in the virion. Most core are conical, with only 7% tubular. The core is constituted by capsid protein hexamer subunits. The core is disassembled soon after virion entry. Interaction with human PPIA/CYPA protects the virus from restriction by human TRIM5-alpha and from an unknown antiviral activity in human cells. This capsid restriction by TRIM5 is one of the factors which restricts HIV-1 to the human species (By similarity). Nucleocapsid protein p7 encapsulates and protects viral dimeric unspliced (genomic) RNA. Binds these RNAs through its zinc fingers. Facilitates rearangement of nucleic acid secondary structure during retrotranscription of genomic RNA. This capability is referred to as nucleic acid chaperone activity (By similarity). The aspartyl protease mediates proteolytic cleavages of Gag and Gag-Pol polyproteins during or shortly after the release of the virion from the plasma membrane. Cleavages take place as an ordered, step-wise cascade to yield mature proteins. This process is called maturation. Displays maximal activity during the budding process just prior to particle release from the cell. Also cleaves Nef and Vif, probably concomitantly with viral structural proteins on maturation of virus particles (By similarity). Reverse transcriptase/ribonuclease H (RT) is a multifunctional enzyme that converts the viral RNA genome into dsDNA in the cytoplasm, shortly after virus entry into the cell. This enzyme displays a DNA polymerase activity that can copy either DNA or RNA templates, and a ribonuclease H (RNase H) activity that cleaves the RNA strand of RNA-DNA heteroduplexes in a partially processive 3' to 5' endonucleasic mode. Conversion of viral genomic RNA into dsDNA requires many steps. A tRNA(3)-Lys binds to the primer-binding site (PBS) situated at the 5'-end of the viral RNA. RT uses the 3' end of the tRNA primer to perform a short round of RNA-dependent minus-strand DNA synthesis. The reading proceeds through the U5 region and ends after the repeated (R) region which is present at both ends of viral RNA. The portion of the RNA-DNA heteroduplex is digested by the RNase H, resulting in a ssDNA product attached to the tRNA primer. This ssDNA/tRNA hybridizes with the identical R region situated at the 3' end of viral RNA. This template exchange, known as minus-strand DNA strong stop transfer, can be either intra- or intermolecular. RT uses the 3' end of this newly synthesized short ssDNA to perform the RNA-dependent minus-strand DNA synthesis of the whole template. RNase H digests the RNA template except for two polypurine tracts (PPTs) situated at the 5'-end and near the center of the genome. It is not clear if both polymerase and RNase H activities are simultaneous. RNase H probably can proceed both in a polymerase-dependent (RNA cut into small fragments by the same RT performing DNA synthesis) and a polymerase-independent mode (cleavage of remaining RNA fragments by free RTs). Secondly, RT performs DNA-directed plus-strand DNA synthesis using the PPTs that have not been removed by RNase H as primers. PPTs and tRNA primers are then removed by RNase H. The 3' and 5' ssDNA PBS regions hybridize to form a circular dsDNA intermediate. Strand displacement synthesis by RT to the PBS and PPT ends produces a blunt ended, linear dsDNA copy of the viral genome that includes long terminal repeats (LTRs) at both ends (By similarity). Integrase catalyzes viral DNA integration into the host chromosome, by performing a series of DNA cutting and joining reactions. This enzyme activity takes place after virion entry into a cell and reverse transcription of the RNA genome in dsDNA. The first step in the integration process is 3' processing. This step requires a complex comprising the viral genome, matrix protein, Vpr and integrase. This complex is called the pre-integration complex (PIC). The integrase protein removes 2 nucleotides from each 3' end of the viral DNA, leaving recessed CA OH's at the 3' ends. In the second step, the PIC enters cell nucleus. This process is mediated through integrase and Vpr proteins, and allows the virus to infect a non dividing cell. This ability to enter the nucleus is specific of lentiviruses, other retroviruses cannot and rely on cell division to access cell chromosomes. In the third step, termed strand transfer, the integrase protein joins the previously processed 3' ends to the 5' ends of strands of target cellular DNA at the site of integration. The 5'-ends are produced by integrase-catalyzed staggered cuts, 5 bp apart. A Y-shaped, gapped, recombination intermediate results, with the 5'-ends of the viral DNA strands and the 3' ends of target DNA strands remaining unjoined, flanking a gap of 5 bp. The last step is viral DNA integration into host chromosome. This involves host DNA repair synthesis in which the 5 bp gaps between the unjoined strands are filled in and then ligated. Since this process occurs at both cuts flanking the HIV genome, a 5 bp duplication of host DNA is produced at the ends of HIV-1 integration. Alternatively, Integrase may catalyze the excision of viral DNA just after strand transfer, this is termed disintegration (By similarity).	+	[[https://www.uniprot.org/uniprot/POL_HV1A2 POL_HV1A2]] Gag-Pol polyprotein and Gag polyprotein may regulate their own translation, by the binding genomic RNA in the 5'-UTR. At low concentration, Gag-Pol and Gag would promote translation, whereas at high concentration, the polyproteins encapsidate genomic RNA and then shutt off translation (By similarity). Matrix protein p17 has two main functions: in infected cell, it targets Gag and Gag-pol polyproteins to the plasma membrane via a multipartite membrane-binding signal, that includes its myristoylated N-terminus. The second function is to play a role in nuclear localization of the viral genome at the very start of cell infection. Matrix protein is the part of the pre-integration complex. It binds in the cytoplasm the human BAF protein which prevent autointegration of the viral genome, and might be included in virions at the ration of zero to 3 BAF dimer per virion. The myristoylation signal and the NLS thus exert conflicting influences its subcellular localization. The key regulation of these motifs might be phosphorylation of a portion of MA molecules on the C-terminal tyrosine at the time of virus maturation, by virion-associated cellular tyrosine kinase. Implicated in the release from host cell mediated by Vpu (By similarity). Capsid protein p24 forms the conical core that encapsulates the genomic RNA-nucleocapsid complex in the virion. Most core are conical, with only 7% tubular. The core is constituted by capsid protein hexamer subunits. The core is disassembled soon after virion entry. Interaction with human PPIA/CYPA protects the virus from restriction by human TRIM5-alpha and from an unknown antiviral activity in human cells. This capsid restriction by TRIM5 is one of the factors which restricts HIV-1 to the human species (By similarity). Nucleocapsid protein p7 encapsulates and protects viral dimeric unspliced (genomic) RNA. Binds these RNAs through its zinc fingers. Facilitates rearangement of nucleic acid secondary structure during retrotranscription of genomic RNA. This capability is referred to as nucleic acid chaperone activity (By similarity). The aspartyl protease mediates proteolytic cleavages of Gag and Gag-Pol polyproteins during or shortly after the release of the virion from the plasma membrane. Cleavages take place as an ordered, step-wise cascade to yield mature proteins. This process is called maturation. Displays maximal activity during the budding process just prior to particle release from the cell. Also cleaves Nef and Vif, probably concomitantly with viral structural proteins on maturation of virus particles (By similarity). Reverse transcriptase/ribonuclease H (RT) is a multifunctional enzyme that converts the viral RNA genome into dsDNA in the cytoplasm, shortly after virus entry into the cell. This enzyme displays a DNA polymerase activity that can copy either DNA or RNA templates, and a ribonuclease H (RNase H) activity that cleaves the RNA strand of RNA-DNA heteroduplexes in a partially processive 3' to 5' endonucleasic mode. Conversion of viral genomic RNA into dsDNA requires many steps. A tRNA(3)-Lys binds to the primer-binding site (PBS) situated at the 5'-end of the viral RNA. RT uses the 3' end of the tRNA primer to perform a short round of RNA-dependent minus-strand DNA synthesis. The reading proceeds through the U5 region and ends after the repeated (R) region which is present at both ends of viral RNA. The portion of the RNA-DNA heteroduplex is digested by the RNase H, resulting in a ssDNA product attached to the tRNA primer. This ssDNA/tRNA hybridizes with the identical R region situated at the 3' end of viral RNA. This template exchange, known as minus-strand DNA strong stop transfer, can be either intra- or intermolecular. RT uses the 3' end of this newly synthesized short ssDNA to perform the RNA-dependent minus-strand DNA synthesis of the whole template. RNase H digests the RNA template except for two polypurine tracts (PPTs) situated at the 5'-end and near the center of the genome. It is not clear if both polymerase and RNase H activities are simultaneous. RNase H probably can proceed both in a polymerase-dependent (RNA cut into small fragments by the same RT performing DNA synthesis) and a polymerase-independent mode (cleavage of remaining RNA fragments by free RTs). Secondly, RT performs DNA-directed plus-strand DNA synthesis using the PPTs that have not been removed by RNase H as primers. PPTs and tRNA primers are then removed by RNase H. The 3' and 5' ssDNA PBS regions hybridize to form a circular dsDNA intermediate. Strand displacement synthesis by RT to the PBS and PPT ends produces a blunt ended, linear dsDNA copy of the viral genome that includes long terminal repeats (LTRs) at both ends (By similarity). Integrase catalyzes viral DNA integration into the host chromosome, by performing a series of DNA cutting and joining reactions. This enzyme activity takes place after virion entry into a cell and reverse transcription of the RNA genome in dsDNA. The first step in the integration process is 3' processing. This step requires a complex comprising the viral genome, matrix protein, Vpr and integrase. This complex is called the pre-integration complex (PIC). The integrase protein removes 2 nucleotides from each 3' end of the viral DNA, leaving recessed CA OH's at the 3' ends. In the second step, the PIC enters cell nucleus. This process is mediated through integrase and Vpr proteins, and allows the virus to infect a non dividing cell. This ability to enter the nucleus is specific of lentiviruses, other retroviruses cannot and rely on cell division to access cell chromosomes. In the third step, termed strand transfer, the integrase protein joins the previously processed 3' ends to the 5' ends of strands of target cellular DNA at the site of integration. The 5'-ends are produced by integrase-catalyzed staggered cuts, 5 bp apart. A Y-shaped, gapped, recombination intermediate results, with the 5'-ends of the viral DNA strands and the 3' ends of target DNA strands remaining unjoined, flanking a gap of 5 bp. The last step is viral DNA integration into host chromosome. This involves host DNA repair synthesis in which the 5 bp gaps between the unjoined strands are filled in and then ligated. Since this process occurs at both cuts flanking the HIV genome, a 5 bp duplication of host DNA is produced at the ends of HIV-1 integration. Alternatively, Integrase may catalyze the excision of viral DNA just after strand transfer, this is termed disintegration (By similarity).
	== Evolutionary Conservation ==		== Evolutionary Conservation ==
	[[Image:Consurf_key_small.gif\|200px\|right]]		[[Image:Consurf_key_small.gif\|200px\|right]]

OCA at 06:56, 12 June 2019

OCA — Wed, 12 Jun 2019 06:56:34 GMT

←Older revision		Revision as of 06:56, 12 June 2019
Line 1:		Line 1:

	==HOW DOES A SYMMETRIC DIMER RECOGNIZE AN ASYMMETRIC SUBSTRATE? A SUBSTRATE COMPLEX OF HIV-1 PROTEASE.==		==HOW DOES A SYMMETRIC DIMER RECOGNIZE AN ASYMMETRIC SUBSTRATE? A SUBSTRATE COMPLEX OF HIV-1 PROTEASE.==
-	<StructureSection load='1f7a' size='340' side='right' caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>	+	<StructureSection load='1f7a' size='340' side='right'caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>
	== Structural highlights ==		== Structural highlights ==
	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F7A OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1F7A FirstGlance]. <br>		<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F7A OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1F7A FirstGlance]. <br>
Line 14:		Line 14:
	Check<jmol>		Check<jmol>
	<jmolCheckbox>		<jmolCheckbox>
-	<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/f7/1f7a_consurf.spt"</scriptWhenChecked>	+	<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/f7/1f7a_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 31:		Line 31:

	==See Also==		==See Also==
-	*[[Immunodeficiency virus protease\|Immunodeficiency virus protease]]	+	*[[Immunodeficiency virus protease 3D structures\|Immunodeficiency virus protease 3D structures]]
	== References ==		== References ==
	<references/>		<references/>
Line 37:		Line 37:
	</StructureSection>		</StructureSection>
	[[Category: HIV-1 retropepsin]]		[[Category: HIV-1 retropepsin]]
		+	[[Category: Large Structures]]
	[[Category: Schiffer, C A]]		[[Category: Schiffer, C A]]
	[[Category: Capsid]]		[[Category: Capsid]]
	[[Category: Hydrolase]]		[[Category: Hydrolase]]
	[[Category: Substrate recognition]]		[[Category: Substrate recognition]]

OCA at 03:45, 6 September 2017

OCA — Wed, 06 Sep 2017 03:45:12 GMT

←Older revision		Revision as of 03:45, 6 September 2017
Line 1:		Line 1:
		+
	==HOW DOES A SYMMETRIC DIMER RECOGNIZE AN ASYMMETRIC SUBSTRATE? A SUBSTRATE COMPLEX OF HIV-1 PROTEASE.==		==HOW DOES A SYMMETRIC DIMER RECOGNIZE AN ASYMMETRIC SUBSTRATE? A SUBSTRATE COMPLEX OF HIV-1 PROTEASE.==
	<StructureSection load='1f7a' size='340' side='right' caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>		<StructureSection load='1f7a' size='340' side='right' caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>
	== Structural highlights ==		== Structural highlights ==
-	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure ~~with sequence from [http://en.wikipedia.org/wiki/9hiv1 9hiv1]~~. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F7A OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1F7A FirstGlance]. <br>	+	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F7A OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1F7A FirstGlance]. <br>
	</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene></td></tr>		</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene></td></tr>
	<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/HIV-1_retropepsin HIV-1 retropepsin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.16 3.4.23.16] </span></td></tr>		<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/HIV-1_retropepsin HIV-1 retropepsin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.16 3.4.23.16] </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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [http://pdbe.org/1f7a PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [http://www.ebi.ac.uk/pdbsum/1f7a 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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [http://pdbe.org/1f7a PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [http://www.ebi.ac.uk/pdbsum/1f7a PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1f7a ProSAT]</span></td></tr>
	</table>		</table>
	== Function ==		== Function ==
Line 17:		Line 18:
	<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=1f7a ConSurf].
	<div style="clear:both"></div>		<div style="clear:both"></div>
	<div style="background-color:#fffaf0;">		<div style="background-color:#fffaf0;">
Line 28:		Line 29:
	</div>		</div>
	<div class="pdbe-citations 1f7a" style="background-color:#fffaf0;"></div>		<div class="pdbe-citations 1f7a" style="background-color:#fffaf0;"></div>
		+
		+	==See Also==
		+	*[[Immunodeficiency virus protease\|Immunodeficiency virus protease]]
	== References ==		== References ==
	<references/>		<references/>

OCA at 16:51, 11 September 2015

OCA — Fri, 11 Sep 2015 16:51:31 GMT

←Older revision		Revision as of 16:51, 11 September 2015
Line 2:		Line 2:
	<StructureSection load='1f7a' size='340' side='right' caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>		<StructureSection load='1f7a' size='340' side='right' caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>
	== Structural highlights ==		== Structural highlights ==
-	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure with sequence from [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=1F7A OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1F7A FirstGlance]. <br>	+	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/9hiv1 9hiv1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F7A OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1F7A FirstGlance]. <br>
	</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene></td></tr>		</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene></td></tr>
	<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/HIV-1_retropepsin HIV-1 retropepsin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.16 3.4.23.16] </span></td></tr>		<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/HIV-1_retropepsin HIV-1 retropepsin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.16 3.4.23.16] </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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [http://www.ebi.ac.uk/pdbsum/1f7a 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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [http://pdbe.org/1f7a PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [http://www.ebi.ac.uk/pdbsum/1f7a PDBsum]</span></td></tr>
	</table>		</table>
	== Function ==		== Function ==
Line 27:		Line 27:
	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 1f7a" style="background-color:#fffaf0;"></div>
	== References ==		== References ==
	<references/>		<references/>
Line 32:		Line 33:
	</StructureSection>		</StructureSection>
	[[Category: HIV-1 retropepsin]]		[[Category: HIV-1 retropepsin]]
-	[[Category: Human immunodeficiency virus 1]]
	[[Category: Schiffer, C A]]		[[Category: Schiffer, C A]]
	[[Category: Capsid]]		[[Category: Capsid]]
	[[Category: Hydrolase]]		[[Category: Hydrolase]]
	[[Category: Substrate recognition]]		[[Category: Substrate recognition]]

OCA at 19:14, 25 December 2014

OCA — Thu, 25 Dec 2014 19:14:48 GMT

←Older revision		Revision as of 19:14, 25 December 2014
Line 7:		Line 7:
	<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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [http://www.ebi.ac.uk/pdbsum/1f7a 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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [http://www.ebi.ac.uk/pdbsum/1f7a PDBsum]</span></td></tr>
	</table>		</table>
		+	== Function ==
		+	[[http://www.uniprot.org/uniprot/POL_HV1A2 POL_HV1A2]] Gag-Pol polyprotein and Gag polyprotein may regulate their own translation, by the binding genomic RNA in the 5'-UTR. At low concentration, Gag-Pol and Gag would promote translation, whereas at high concentration, the polyproteins encapsidate genomic RNA and then shutt off translation (By similarity). Matrix protein p17 has two main functions: in infected cell, it targets Gag and Gag-pol polyproteins to the plasma membrane via a multipartite membrane-binding signal, that includes its myristoylated N-terminus. The second function is to play a role in nuclear localization of the viral genome at the very start of cell infection. Matrix protein is the part of the pre-integration complex. It binds in the cytoplasm the human BAF protein which prevent autointegration of the viral genome, and might be included in virions at the ration of zero to 3 BAF dimer per virion. The myristoylation signal and the NLS thus exert conflicting influences its subcellular localization. The key regulation of these motifs might be phosphorylation of a portion of MA molecules on the C-terminal tyrosine at the time of virus maturation, by virion-associated cellular tyrosine kinase. Implicated in the release from host cell mediated by Vpu (By similarity). Capsid protein p24 forms the conical core that encapsulates the genomic RNA-nucleocapsid complex in the virion. Most core are conical, with only 7% tubular. The core is constituted by capsid protein hexamer subunits. The core is disassembled soon after virion entry. Interaction with human PPIA/CYPA protects the virus from restriction by human TRIM5-alpha and from an unknown antiviral activity in human cells. This capsid restriction by TRIM5 is one of the factors which restricts HIV-1 to the human species (By similarity). Nucleocapsid protein p7 encapsulates and protects viral dimeric unspliced (genomic) RNA. Binds these RNAs through its zinc fingers. Facilitates rearangement of nucleic acid secondary structure during retrotranscription of genomic RNA. This capability is referred to as nucleic acid chaperone activity (By similarity). The aspartyl protease mediates proteolytic cleavages of Gag and Gag-Pol polyproteins during or shortly after the release of the virion from the plasma membrane. Cleavages take place as an ordered, step-wise cascade to yield mature proteins. This process is called maturation. Displays maximal activity during the budding process just prior to particle release from the cell. Also cleaves Nef and Vif, probably concomitantly with viral structural proteins on maturation of virus particles (By similarity). Reverse transcriptase/ribonuclease H (RT) is a multifunctional enzyme that converts the viral RNA genome into dsDNA in the cytoplasm, shortly after virus entry into the cell. This enzyme displays a DNA polymerase activity that can copy either DNA or RNA templates, and a ribonuclease H (RNase H) activity that cleaves the RNA strand of RNA-DNA heteroduplexes in a partially processive 3' to 5' endonucleasic mode. Conversion of viral genomic RNA into dsDNA requires many steps. A tRNA(3)-Lys binds to the primer-binding site (PBS) situated at the 5'-end of the viral RNA. RT uses the 3' end of the tRNA primer to perform a short round of RNA-dependent minus-strand DNA synthesis. The reading proceeds through the U5 region and ends after the repeated (R) region which is present at both ends of viral RNA. The portion of the RNA-DNA heteroduplex is digested by the RNase H, resulting in a ssDNA product attached to the tRNA primer. This ssDNA/tRNA hybridizes with the identical R region situated at the 3' end of viral RNA. This template exchange, known as minus-strand DNA strong stop transfer, can be either intra- or intermolecular. RT uses the 3' end of this newly synthesized short ssDNA to perform the RNA-dependent minus-strand DNA synthesis of the whole template. RNase H digests the RNA template except for two polypurine tracts (PPTs) situated at the 5'-end and near the center of the genome. It is not clear if both polymerase and RNase H activities are simultaneous. RNase H probably can proceed both in a polymerase-dependent (RNA cut into small fragments by the same RT performing DNA synthesis) and a polymerase-independent mode (cleavage of remaining RNA fragments by free RTs). Secondly, RT performs DNA-directed plus-strand DNA synthesis using the PPTs that have not been removed by RNase H as primers. PPTs and tRNA primers are then removed by RNase H. The 3' and 5' ssDNA PBS regions hybridize to form a circular dsDNA intermediate. Strand displacement synthesis by RT to the PBS and PPT ends produces a blunt ended, linear dsDNA copy of the viral genome that includes long terminal repeats (LTRs) at both ends (By similarity). Integrase catalyzes viral DNA integration into the host chromosome, by performing a series of DNA cutting and joining reactions. This enzyme activity takes place after virion entry into a cell and reverse transcription of the RNA genome in dsDNA. The first step in the integration process is 3' processing. This step requires a complex comprising the viral genome, matrix protein, Vpr and integrase. This complex is called the pre-integration complex (PIC). The integrase protein removes 2 nucleotides from each 3' end of the viral DNA, leaving recessed CA OH's at the 3' ends. In the second step, the PIC enters cell nucleus. This process is mediated through integrase and Vpr proteins, and allows the virus to infect a non dividing cell. This ability to enter the nucleus is specific of lentiviruses, other retroviruses cannot and rely on cell division to access cell chromosomes. In the third step, termed strand transfer, the integrase protein joins the previously processed 3' ends to the 5' ends of strands of target cellular DNA at the site of integration. The 5'-ends are produced by integrase-catalyzed staggered cuts, 5 bp apart. A Y-shaped, gapped, recombination intermediate results, with the 5'-ends of the viral DNA strands and the 3' ends of target DNA strands remaining unjoined, flanking a gap of 5 bp. The last step is viral DNA integration into host chromosome. This involves host DNA repair synthesis in which the 5 bp gaps between the unjoined strands are filled in and then ligated. Since this process occurs at both cuts flanking the HIV genome, a 5 bp duplication of host DNA is produced at the ends of HIV-1 integration. Alternatively, Integrase may catalyze the excision of viral DNA just after strand transfer, this is termed disintegration (By similarity).
	== Evolutionary Conservation ==		== Evolutionary Conservation ==
	[[Image:Consurf_key_small.gif\|200px\|right]]		[[Image:Consurf_key_small.gif\|200px\|right]]

OCA at 18:39, 22 December 2014

OCA — Mon, 22 Dec 2014 18:39:36 GMT

←Older revision		Revision as of 18:39, 22 December 2014
Line 3:		Line 3:
	== Structural highlights ==		== Structural highlights ==
	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure with sequence from [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=1F7A OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1F7A FirstGlance]. <br>		<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure with sequence from [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=1F7A OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1F7A FirstGlance]. <br>
-	</td></tr><tr><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene><br>	+	</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene></td></tr>
-	<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/HIV-1_retropepsin HIV-1 retropepsin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.16 3.4.23.16] </span></td></tr>	+	<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/HIV-1_retropepsin HIV-1 retropepsin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.16 3.4.23.16] </span></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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [http://www.ebi.ac.uk/pdbsum/1f7a 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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [http://www.ebi.ac.uk/pdbsum/1f7a 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 31:		Line 31:
	[[Category: HIV-1 retropepsin]]		[[Category: HIV-1 retropepsin]]
	[[Category: Human immunodeficiency virus 1]]		[[Category: Human immunodeficiency virus 1]]
-	[[Category: Schiffer, C A.]]	+	[[Category: Schiffer, C A]]
	[[Category: Capsid]]		[[Category: Capsid]]
	[[Category: Hydrolase]]		[[Category: Hydrolase]]
	[[Category: Substrate recognition]]		[[Category: Substrate recognition]]

OCA at 08:42, 28 September 2014

OCA — Sun, 28 Sep 2014 08:42:26 GMT

←Older revision		Revision as of 08:42, 28 September 2014
Line 1:		Line 1:
-	[[~~Image~~:1f7a.~~png\|left~~\|200px]]	+	==HOW DOES A SYMMETRIC DIMER RECOGNIZE AN ASYMMETRIC SUBSTRATE? A SUBSTRATE COMPLEX OF HIV-1 PROTEASE.==
		+	<StructureSection load='1f7a' size='340' side='right' caption='[[1f7a]], [[Resolution\|resolution]] 2.00Å' scene=''>
		+	== Structural highlights ==
		+	<table><tr><td colspan='2'>[[1f7a]] is a 3 chain structure with sequence from [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=1F7A OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1F7A FirstGlance]. <br>
		+	</td></tr><tr><td class="sblockLbl"><b>[[Ligand\|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene><br>
		+	<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/HIV-1_retropepsin HIV-1 retropepsin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.16 3.4.23.16] </span></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=1f7a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f7a OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1f7a RCSB], [http://www.ebi.ac.uk/pdbsum/1f7a 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/f7/1f7a_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 crystal structure of an actual HIV-1 protease-substrate complex is presented at 2.0 A resolution (R-value of 19.7 % (R(free) 23.3 %)) between an inactive variant (D25N) of HIV-1 protease and a long substrate peptide, Lys-Ala-Arg-Val-Leu-Ala-Glu-Ala-Met-Ser, which covers a full binding epitope of capsid(CA)-p2, cleavage site. The substrate peptide is asymmetric in both size and charge distribution. To accommodate this asymmetry the two protease monomers adopt different conformations burying a total of 1038 A(2) of surface area at the protease-substrate interface. The specificity for the CA-p2 substrate peptide is mainly hydrophobic, as most of the hydrogen bonds are made with the backbone of the peptide substrate. Two water molecules bridge the two monomers through the loops Gly49-Gly52 (Gly49'-Gly52') and Pro79'-Val82' (Pro79-Val82). When other complexes are compared, the mobility of these loops is correlated with the content of the P1 and P1' sites. Interdependence of the conformational changes allows the protease to exhibit its wide range of substrate specificity.

-	~~{{STRUCTURE_1f7a\| PDB=1f7a \| SCENE= }}~~	+	How does a symmetric dimer recognize an asymmetric substrate? A substrate complex of HIV-1 protease.,Prabu-Jeyabalan M, Nalivaika E, Schiffer CA J Mol Biol. 2000 Sep 1;301(5):1207-20. PMID:10966816<ref>PMID:10966816</ref>

-	~~===HOW DOES A SYMMETRIC DIMER RECOGNIZE AN ASYMMETRIC SUBSTRATE? A SUBSTRATE COMPLEX OF HIV-1 PROTEASE.===~~	+	From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
-		+	</div>
-		+	== References ==
-	~~==About this Structure==~~	+	<references/>
-	~~[[1f7a]] is~~ a ~~3 chain structure with sequence from [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=1F7A OCA].~~	+	__TOC__
-		+	</StructureSection>
-	==~~Reference~~==	+
-	<~~ref group="xtra">PMID:010966816<~~/~~ref~~><~~references group="xtra"~~/>	+
	[[Category: HIV-1 retropepsin]]		[[Category: HIV-1 retropepsin]]
	[[Category: Human immunodeficiency virus 1]]		[[Category: Human immunodeficiency virus 1]]

OCA: Protected "1f7a" [edit=sysop:move=sysop]

OCA — Wed, 14 Nov 2012 07:21:23 GMT

Protected "1f7a" [edit=sysop:move=sysop]

←Older revision

Revision as of 07:21, 14 November 2012