| Structural highlights
3si0 is a 1 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | , , , |
| Related: | 3si1, 3si2 |
| Gene: | QPCT (HUMAN) |
| Activity: | Glutaminyl-peptide cyclotransferase, with EC number 2.3.2.5 |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[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.[1] [2] [3]
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[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Schilling S, Hoffmann T, Manhart S, Hoffmann M, Demuth HU. Glutaminyl cyclases unfold glutamyl cyclase activity under mild acid conditions. FEBS Lett. 2004 Apr 9;563(1-3):191-6. PMID:15063747 doi:http://dx.doi.org/10.1016/S0014-5793(04)00300-X
- ↑ Cynis H, Rahfeld JU, Stephan A, Kehlen A, Koch B, Wermann M, Demuth HU, Schilling S. Isolation of an isoenzyme of human glutaminyl cyclase: retention in the Golgi complex suggests involvement in the protein maturation machinery. J Mol Biol. 2008 Jun 20;379(5):966-80. doi: 10.1016/j.jmb.2008.03.078. Epub 2008 , Apr 15. PMID:18486145 doi:http://dx.doi.org/10.1016/j.jmb.2008.03.078
- ↑ Huang KF, Liaw SS, Huang WL, Chia CY, Lo YC, Chen YL, Wang AH. Structures of human Golgi-resident glutaminyl cyclase and its complexes with inhibitors reveal a large loop movement upon inhibitor binding. J Biol Chem. 2011 Apr 8;286(14):12439-49. Epub 2011 Feb 1. PMID:21288892 doi:10.1074/jbc.M110.208595
- ↑ 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. Structures of Glycosylated Mammalian Glutaminyl Cyclases Reveal Conformational Variability near the Active Center. Biochemistry. 2011 Jun 27. PMID:21671571 doi:10.1021/bi200249h
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