View source for 3si0


==Structure of glycosylated human glutaminyl cyclase==
<StructureSection load='3si0' size='340' side='right'caption='[[3si0]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3si0]] 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=3SI0 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3SI0 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.1&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=IMD:IMIDAZOLE'>IMD</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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=3si0 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3si0 OCA], [https://pdbe.org/3si0 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3si0 RCSB], [https://www.ebi.ac.uk/pdbsum/3si0 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3si0 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/QPCT_HUMAN QPCT_HUMAN] Responsible for the biosynthesis of pyroglutamyl peptides. Has a bias against acidic and tryptophan residues adjacent to the N-terminal glutaminyl residue and a lack of importance of chain length after the second residue. Also catalyzes N-terminal pyroglutamate formation. In vitro, catalyzes pyroglutamate formation of N-terminally truncated form of APP amyloid-beta peptides [Glu-3]-beta-amyloid. May be involved in the N-terminal pyroglutamate formation of several amyloid-related plaque-forming peptides.<ref>PMID:15063747</ref> <ref>PMID:18486145</ref> <ref>PMID:21288892</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Formation of N-terminal pyroglutamate (pGlu or pE) from glutaminyl or glutamyl precursors is catalyzed by glutaminyl cyclases (QC). As the formation of pGlu-amyloid has been linked with Alzheimer's disease, inhibitors of QCs are currently the subject of intense development. Here, we report three crystal structures of N-glycosylated mammalian QC from humans (hQC) and mice (mQC). Whereas the overall structures of the enzymes are similar to those reported previously, two surface loops in the neighborhood of the active center exhibit conformational variability. Furthermore, two conserved cysteine residues form a disulfide bond at the base of the active center that was not present in previous reports of hQC structure. Site-directed mutagenesis suggests a structure-stabilizing role of the disulfide bond. At the entrance to the active center, the conserved tryptophan residue, W(207), which displayed multiple orientations in previous structure, shows a single conformation in both glycosylated human and murine QCs. Although mutagenesis of W(207) into leucine or glutamine altered substrate conversion significantly, the binding constants of inhibitors such as the highly potent PQ50 (PBD150) were minimally affected. The crystal structure of PQ50 bound to the active center of murine QC reveals principal binding determinants provided by the catalytic zinc ion and a hydrophobic funnel. This study presents a first comparison of two mammalian QCs containing typical, conserved post-translational modifications.

Structures of Glycosylated Mammalian Glutaminyl Cyclases Reveal Conformational Variability near the Active Center.,Ruiz-Carrillo D, Koch B, Parthier C, Wermann M, Dambe T, Buchholz M, Ludwig HH, Heiser U, Rahfeld JU, Stubbs MT, Schilling S, Demuth HU Biochemistry. 2011 Jun 27. PMID:21671571<ref>PMID:21671571</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3si0" style="background-color:#fffaf0;"></div>

==See Also==
*[[Glutaminyl cyclase|Glutaminyl cyclase]]
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Carrillo D]]
[[Category: Parthier C]]
[[Category: Stubbs MT]]