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| | ==Alternative conformations of the x region of human protein disulphide-isomerase modulate exposure of the substrate binding b' domain== | | ==Alternative conformations of the x region of human protein disulphide-isomerase modulate exposure of the substrate binding b' domain== |
| - | <StructureSection load='3bj5' size='340' side='right' caption='[[3bj5]], [[Resolution|resolution]] 2.20Å' scene=''> | + | <StructureSection load='3bj5' size='340' side='right'caption='[[3bj5]], [[Resolution|resolution]] 2.20Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[3bj5]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3BJ5 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3BJ5 FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[3bj5]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3BJ5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3BJ5 FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</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]] 2.2Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">P4HB, ERBA2L, PDI, PDIA1, PO4DB ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr>
| + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> |
| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Protein_disulfide-isomerase Protein disulfide-isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.4.1 5.3.4.1] </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=3bj5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3bj5 OCA], [https://pdbe.org/3bj5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3bj5 RCSB], [https://www.ebi.ac.uk/pdbsum/3bj5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3bj5 ProSAT]</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=3bj5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3bj5 OCA], [http://pdbe.org/3bj5 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3bj5 RCSB], [http://www.ebi.ac.uk/pdbsum/3bj5 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3bj5 ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/PDIA1_HUMAN PDIA1_HUMAN]] This multifunctional protein catalyzes the formation, breakage and rearrangement of disulfide bonds. At the cell surface, seems to act as a reductase that cleaves disulfide bonds of proteins attached to the cell. May therefore cause structural modifications of exofacial proteins. Inside the cell, seems to form/rearrange disulfide bonds of nascent proteins. At high concentrations, functions as a chaperone that inhibits aggregation of misfolded proteins. At low concentrations, facilitates aggregation (anti-chaperone activity). May be involved with other chaperones in the structural modification of the TG precursor in hormone biogenesis. Also acts a structural subunit of various enzymes such as prolyl 4-hydroxylase and microsomal triacylglycerol transfer protein MTTP.<ref>PMID:10636893</ref> <ref>PMID:12485997</ref> | + | [https://www.uniprot.org/uniprot/PDIA1_HUMAN PDIA1_HUMAN] This multifunctional protein catalyzes the formation, breakage and rearrangement of disulfide bonds. At the cell surface, seems to act as a reductase that cleaves disulfide bonds of proteins attached to the cell. May therefore cause structural modifications of exofacial proteins. Inside the cell, seems to form/rearrange disulfide bonds of nascent proteins. At high concentrations, functions as a chaperone that inhibits aggregation of misfolded proteins. At low concentrations, facilitates aggregation (anti-chaperone activity). May be involved with other chaperones in the structural modification of the TG precursor in hormone biogenesis. Also acts a structural subunit of various enzymes such as prolyl 4-hydroxylase and microsomal triacylglycerol transfer protein MTTP.<ref>PMID:10636893</ref> <ref>PMID:12485997</ref> |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Human]] | + | [[Category: Homo sapiens]] |
| - | [[Category: Protein disulfide-isomerase]] | + | [[Category: Large Structures]] |
| - | [[Category: Haapalainen, A M]] | + | [[Category: Haapalainen AM]] |
| - | [[Category: Nguyen, V D]] | + | [[Category: Nguyen VD]] |
| - | [[Category: Ruddock, L W]] | + | [[Category: Ruddock LW]] |
| - | [[Category: Wierenga, R K]] | + | [[Category: Wierenga RK]] |
| - | [[Category: Chaperone]]
| + | |
| - | [[Category: Endoplasmic reticulum]]
| + | |
| - | [[Category: Isomerase]]
| + | |
| - | [[Category: Membrane]]
| + | |
| - | [[Category: Redox-active center]]
| + | |
| - | [[Category: Thioredoxin fold]]
| + | |
| Structural highlights
Function
PDIA1_HUMAN This multifunctional protein catalyzes the formation, breakage and rearrangement of disulfide bonds. At the cell surface, seems to act as a reductase that cleaves disulfide bonds of proteins attached to the cell. May therefore cause structural modifications of exofacial proteins. Inside the cell, seems to form/rearrange disulfide bonds of nascent proteins. At high concentrations, functions as a chaperone that inhibits aggregation of misfolded proteins. At low concentrations, facilitates aggregation (anti-chaperone activity). May be involved with other chaperones in the structural modification of the TG precursor in hormone biogenesis. Also acts a structural subunit of various enzymes such as prolyl 4-hydroxylase and microsomal triacylglycerol transfer protein MTTP.[1] [2]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Protein disulphide isomerase (PDI) is a key multi-domain protein folding catalyst in the endoplasmic reticulum. The b' domain of PDI is essential for the non-covalent binding of incompletely folded protein substrates. Earlier, we defined the substrate binding site in the b' domain of human PDI by modelling and mutagenesis studies. Here, we show by fluorescence and NMR that recombinant human PDI b'x (comprising the b' domain and the subsequent x linker region) can assume at least two different conformations in solution. We have screened mutants in the b'x region to identify mutations that favour one of these conformers in recombinant b'x, and isolated and characterised examples of both types. We have crystallised one mutant of b'x (I272A mutation) in which one conformer is stabilized, and determined its crystal structure to a resolution of 2.2 A. This structure shows that the b' domain has the typical thioredoxin fold and that the x region can interact with the b' domain by "capping" a hydrophobic site on the b' domain. This site is most likely the substrate binding site and hence such capping will inhibit substrate binding. All of the mutations we previously reported to inhibit substrate binding shift the equilibrium towards the capped conformer. Hence, these mutations act by altering the natural equilibrium and decreasing the accessibility of the substrate binding site. Furthermore, we have confirmed that the corresponding structural transition occurs in the wild type full-length PDI. A cross-comparison of our data with that for other PDI-family members, Pdi1p and ERp44, suggests that the x region of PDI can adopt alternative conformations during the functional cycle of PDI action and that these are linked to the ability of PDI to interact with folding substrates.
Alternative conformations of the x region of human protein disulphide-isomerase modulate exposure of the substrate binding b' domain.,Nguyen VD, Wallis K, Howard MJ, Haapalainen AM, Salo KE, Saaranen MJ, Sidhu A, Wierenga RK, Freedman RB, Ruddock LW, Williamson RA J Mol Biol. 2008 Nov 28;383(5):1144-55. Epub 2008 Sep 9. PMID:18801374[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Mezghrani A, Courageot J, Mani JC, Pugniere M, Bastiani P, Miquelis R. Protein-disulfide isomerase (PDI) in FRTL5 cells. pH-dependent thyroglobulin/PDI interactions determine a novel PDI function in the post-endoplasmic reticulum of thyrocytes. J Biol Chem. 2000 Jan 21;275(3):1920-9. PMID:10636893
- ↑ Lumb RA, Bulleid NJ. Is protein disulfide isomerase a redox-dependent molecular chaperone? EMBO J. 2002 Dec 16;21(24):6763-70. PMID:12485997
- ↑ Nguyen VD, Wallis K, Howard MJ, Haapalainen AM, Salo KE, Saaranen MJ, Sidhu A, Wierenga RK, Freedman RB, Ruddock LW, Williamson RA. Alternative conformations of the x region of human protein disulphide-isomerase modulate exposure of the substrate binding b' domain. J Mol Biol. 2008 Nov 28;383(5):1144-55. Epub 2008 Sep 9. PMID:18801374 doi:http://dx.doi.org/10.1016/j.jmb.2008.08.085
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