2zel: Difference between revisions
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[[Image: | ==Crystal structure of the human glutaminyl cyclase mutant D248A at 1.97 angstrom resolution== | ||
<StructureSection load='2zel' size='340' side='right' caption='[[2zel]], [[Resolution|resolution]] 1.97Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[2zel]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2ZEL OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2ZEL FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene><br> | |||
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[2afm|2afm]], [[2zed|2zed]], [[2zee|2zee]], [[2zef|2zef]], [[2zeg|2zeg]], [[2zeh|2zeh]], [[2zem|2zem]], [[2zen|2zen]], [[2zeo|2zeo]], [[2zep|2zep]]</td></tr> | |||
<tr><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">QPCT ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens])</td></tr> | |||
<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Glutaminyl-peptide_cyclotransferase Glutaminyl-peptide cyclotransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.2.5 2.3.2.5] </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=2zel FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2zel OCA], [http://www.rcsb.org/pdb/explore.do?structureId=2zel RCSB], [http://www.ebi.ac.uk/pdbsum/2zel 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/ze/2zel_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 == | |||
QCs (glutaminyl cyclases; glutaminyl-peptide cyclotransferases, EC 2.3.2.5) catalyse N-terminal pyroglutamate formation in numerous bioactive peptides and proteins. The enzymes were reported to be involved in several pathological conditions such as amyloidotic disease, osteoporosis, rheumatoid arthritis and melanoma. The crystal structure of human QC revealed an unusual H-bond (hydrogen-bond) network in the active site, formed by several highly conserved residues (Ser(160), Glu(201), Asp(248), Asp(305) and His(319)), within which Glu(201) and Asp(248) were found to bind to substrate. In the present study we combined steady-state enzyme kinetic and X-ray structural analyses of 11 single-mutation human QCs to investigate the roles of the H-bond network in catalysis. Our results showed that disrupting one or both of the central H-bonds, i.e., Glu(201)...Asp(305) and Asp(248)...Asp(305), reduced the steady-state catalysis dramatically. The roles of these two COOH...COOH bonds on catalysis could be partly replaced by COOH...water bonds, but not by COOH...CONH(2) bonds, reminiscent of the low-barrier Asp...Asp H-bond in the active site of pepsin-like aspartic peptidases. Mutations on Asp(305), a residue located at the centre of the H-bond network, raised the K(m) value of the enzyme by 4.4-19-fold, but decreased the k(cat) value by 79-2842-fold, indicating that Asp(305) primarily plays a catalytic role. In addition, results from mutational studies on Ser(160) and His(319) suggest that these two residues might help to stabilize the conformations of Asp(248) and Asp(305) respectively. These data allow us to propose an essential proton transfer between Glu(201), Asp(305) and Asp(248) during the catalysis by animal QCs. | |||
A conserved hydrogen-bond network in the catalytic centre of animal glutaminyl cyclases is critical for catalysis.,Huang KF, Wang YR, Chang EC, Chou TL, Wang AH Biochem J. 2008 Apr 1;411(1):181-90. PMID:18072935<ref>PMID:18072935</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | |||
*[[Glutaminyl cyclase|Glutaminyl cyclase]] | |||
== | == References == | ||
[[ | <references/> | ||
__TOC__ | |||
== | </StructureSection> | ||
< | |||
[[Category: Glutaminyl-peptide cyclotransferase]] | [[Category: Glutaminyl-peptide cyclotransferase]] | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
Revision as of 08:10, 2 October 2014
Crystal structure of the human glutaminyl cyclase mutant D248A at 1.97 angstrom resolutionCrystal structure of the human glutaminyl cyclase mutant D248A at 1.97 angstrom resolution
Structural highlights
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 PubMedQCs (glutaminyl cyclases; glutaminyl-peptide cyclotransferases, EC 2.3.2.5) catalyse N-terminal pyroglutamate formation in numerous bioactive peptides and proteins. The enzymes were reported to be involved in several pathological conditions such as amyloidotic disease, osteoporosis, rheumatoid arthritis and melanoma. The crystal structure of human QC revealed an unusual H-bond (hydrogen-bond) network in the active site, formed by several highly conserved residues (Ser(160), Glu(201), Asp(248), Asp(305) and His(319)), within which Glu(201) and Asp(248) were found to bind to substrate. In the present study we combined steady-state enzyme kinetic and X-ray structural analyses of 11 single-mutation human QCs to investigate the roles of the H-bond network in catalysis. Our results showed that disrupting one or both of the central H-bonds, i.e., Glu(201)...Asp(305) and Asp(248)...Asp(305), reduced the steady-state catalysis dramatically. The roles of these two COOH...COOH bonds on catalysis could be partly replaced by COOH...water bonds, but not by COOH...CONH(2) bonds, reminiscent of the low-barrier Asp...Asp H-bond in the active site of pepsin-like aspartic peptidases. Mutations on Asp(305), a residue located at the centre of the H-bond network, raised the K(m) value of the enzyme by 4.4-19-fold, but decreased the k(cat) value by 79-2842-fold, indicating that Asp(305) primarily plays a catalytic role. In addition, results from mutational studies on Ser(160) and His(319) suggest that these two residues might help to stabilize the conformations of Asp(248) and Asp(305) respectively. These data allow us to propose an essential proton transfer between Glu(201), Asp(305) and Asp(248) during the catalysis by animal QCs. A conserved hydrogen-bond network in the catalytic centre of animal glutaminyl cyclases is critical for catalysis.,Huang KF, Wang YR, Chang EC, Chou TL, Wang AH Biochem J. 2008 Apr 1;411(1):181-90. PMID:18072935[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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