7d23

Crystal structure of Ixodes scapularis glutaminyl cyclase with one K ion bound to the active site

spinqualitylabelsall models 7d23, resolution 1.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7d23 is a 1 chain structure with sequence from Ixodes scapularis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.4Å Ligands: K, TRS Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function QPCT_IXOSC Responsible for the biosynthesis of pyroglutamyl peptides (PubMed:23770496, PubMed:24598748). Seems to have a preference for substrates with neutral or hydrophobic amino-acid residues at the second and third positions (PubMed:24598748). Shows activity towards the peptides [Gln-1]-corazonin, [Gln-1]-periviscerokinin and [Gln-1]-sulfakinin (PubMed:24598748). Publication Abstract from PubMed Proteins with sequence or structure similar to those of di-Zn exopeptidases are usually classified as the M28-family enzymes, including the mammalian-type glutaminyl cyclases (QCs). QC catalyzes protein N-terminal pyroglutamate formation, a posttranslational modification important under many physiological and pathological conditions, and is a drug target for treating neurodegenerative diseases, cancers and inflammatory disorders. Without functional characterization, mammalian QCs and their orthologs remain indistinguishable at the sequence and structure levels from other M28-family proteins, leading to few reported QCs. Here, we show that a low-barrier carboxylic-acid hydrogen-bond network (CAHBN) is required for QC activity and discriminates QCs from M28-family peptidases. We demonstrate that the CAHBN-containing M28 peptidases deposited in the PDB are indeed QCs. Our analyses identify several thousands of QCs from the three domains of life, and we enzymatically and structurally characterize several. For the first time, the interplay between a CAHBN and the binuclear metal-binding center of mammalian QCs is made clear. We found that the presence or absence of CAHBN is a key discriminator for the formation of either the mono-Zn QCs or the di-Zn exopeptidases. Our study helps explain the possible roles of QCs in life. A unique carboxylic-acid hydrogen-bond network (CAHBN) confers glutaminyl cyclase activity on M28 family enzymes.,Huang KF, Huang JS, Wu ML, Hsieh WL, Hsu KC, Hsu HL, Ko TP, H-J Wang A J Mol Biol. 2021 Mar 24:166960. doi: 10.1016/j.jmb.2021.166960. PMID:33774034 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Glutaminyl cyclase

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