ID   QPCT_CROAT              Reviewed;          71 AA.
AC   P0CV92;
DT   03-MAY-2011, integrated into UniProtKB/Swiss-Prot.
DT   03-MAY-2011, sequence version 1.
DT   03-AUG-2022, entry version 24.
DE   RecName: Full=Glutaminyl-peptide cyclotransferase;
DE            EC=2.3.2.5;
DE   AltName: Full=Glutaminyl cyclase;
DE            Short=QC;
DE   Flags: Fragments;
GN   Name=QPCT;
OS   Crotalus atrox (Western diamondback rattlesnake).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Viperidae; Crotalinae; Crotalus.
OX   NCBI_TaxID=8730;
RN   [1]
RP   PROTEIN SEQUENCE, SUBCELLULAR LOCATION, AND IDENTIFICATION BY MASS
RP   SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=19371136; DOI=10.1021/pr900249q;
RA   Calvete J.J., Fasoli E., Sanz L., Boschetti E., Righetti P.G.;
RT   "Exploring the venom proteome of the western diamondback rattlesnake,
RT   Crotalus atrox, via snake venomics and combinatorial peptide ligand library
RT   approaches.";
RL   J. Proteome Res. 8:3055-3067(2009).
CC   -!- FUNCTION: Responsible for the biosynthesis of pyroglutamyl peptides.
CC       Has a bias against acidic and tryptophan residues adjacent to the N-
CC       terminal glutaminyl residue and a lack of importance of chain length
CC       after the second residue. Also catalyzes N-terminal pyroglutamate
CC       formation (By similarity). {ECO:0000250}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=N-terminal L-glutaminyl-[peptide] = N-terminal 5-oxo-L-prolyl-
CC         [peptide] + NH4(+); Xref=Rhea:RHEA:23652, Rhea:RHEA-COMP:11736,
CC         Rhea:RHEA-COMP:11846, ChEBI:CHEBI:28938, ChEBI:CHEBI:64722,
CC         ChEBI:CHEBI:87215; EC=2.3.2.5;
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:19371136}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- SIMILARITY: Belongs to the glutaminyl-peptide cyclotransferase family.
CC       {ECO:0000305}.
CC   -!- CAUTION: It is unclear whether this protein requires a metal cofactor
CC       for catalysis. It was originally proposed to be a Zn(2+)-dependent
CC       metalloenzyme based on structural similarities to bacterial
CC       aminopeptidases and the observation that it can bind Zn(2+) ions,
CC       typically in a 1:1 stoichiometry (By similarity). However, a recent
CC       study suggests a Zn(2+)-independent catalytic mechanism (By
CC       similarity). {ECO:0000250|UniProtKB:B7QK46,
CC       ECO:0000250|UniProtKB:Q16769}.
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DR   AlphaFoldDB; P0CV92; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0016603; F:glutaminyl-peptide cyclotransferase activity; ISS:UniProtKB.
DR   GO; GO:0008270; F:zinc ion binding; ISS:UniProtKB.
DR   GO; GO:0017186; P:peptidyl-pyroglutamic acid biosynthetic process, using glutaminyl-peptide cyclotransferase; ISS:UniProtKB.
DR   InterPro; IPR040234; QC/QCL.
DR   PANTHER; PTHR12283; PTHR12283; 2.
PE   1: Evidence at protein level;
KW   Acyltransferase; Direct protein sequencing; Metal-binding; Secreted;
KW   Transferase; Zinc.
FT   CHAIN           <1..>71
FT                   /note="Glutaminyl-peptide cyclotransferase"
FT                   /id="PRO_0000407592"
FT   ACT_SITE        18
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000250|UniProtKB:Q16769"
FT   BINDING         19
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000250|UniProtKB:Q16769"
FT   NON_CONS        11..12
FT                   /evidence="ECO:0000305"
FT   NON_CONS        34..35
FT                   /evidence="ECO:0000305"
FT   NON_CONS        44..45
FT                   /evidence="ECO:0000305"
FT   NON_CONS        56..57
FT                   /evidence="ECO:0000305"
FT   NON_TER         1
FT   NON_TER         71
SQ   SEQUENCE   71 AA;  7899 MW;  94E3055F2B09C66F CRC64;
     YPGSPGSYAV RLIFFDGEEA FVRWSPSDSL YGSRMASTPH PPGARHPVED DHIPFLRGVP
     ILHLIPSPFP R