Structural highlights
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
Glutaminyl-peptide cyclotransferases (QCs) convert the N-terminal glutamine or glutamate residues of protein and peptide substrates into pyroglutamate (pE) by releasing ammonia or a water molecule. The N-terminal pE modification protects peptides/proteins against proteolytic degradation by amino- or exopeptidases, increasing their stability. Mammalian QC is abundant in the brain and a large amount of evidence indicates that pE peptides are involved in the onset of neural human pathologies such as Alzheimer's and Huntington's disease and synucleinopathies. Hence, human QC (hQC) has become an intensively studied target for drug development against these diseases. Soon after its characterization, hQC was identified as a Zn-dependent enzyme, but a partial restoration of the enzyme activity in the presence of the Co(II) ion was also reported, suggesting a possible role of this metal ion in catalysis. The present work aims to investigate the structure of demetallated hQC and of the reconstituted enzyme with Zn(II) and Co(II) and their behavior in the presence of known inhibitors. Furthermore, our structural determinations provide a possible explanation for the presence of the mononuclear metal binding site of hQC, despite the presence of the same conserved metal binding motifs present in distantly related dinuclear aminopeptidase enzymes.
Metal Ion Binding to Human Glutaminyl Cyclase: A Structural Perspective.,Tassone G, Pozzi C, Mangani S Int J Mol Sci. 2024 Jul 29;25(15):8279. doi: 10.3390/ijms25158279. PMID:39125848[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
- ↑ Tassone G, Pozzi C, Mangani S. Metal Ion Binding to Human Glutaminyl Cyclase: A Structural Perspective. Int J Mol Sci. 2024 Jul 29;25(15):8279. PMID:39125848 doi:10.3390/ijms25158279
