ID   PA2B_BITAR              Reviewed;          35 AA.
AC   P0DKT6;
DT   09-JAN-2013, integrated into UniProtKB/Swiss-Prot.
DT   09-JAN-2013, sequence version 1.
DT   25-MAY-2022, entry version 21.
DE   RecName: Full=Phospholipase A2 bitanarin;
DE            Short=svPLA2;
DE            EC=3.1.1.4;
DE   AltName: Full=Bitis arietans nicotinic acetylcholine receptor inhibitor;
DE   AltName: Full=Phosphatidylcholine 2-acylhydrolase;
DE   Flags: Fragments;
OS   Bitis arietans (African puff adder).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Viperidae; Viperinae; Bitis.
OX   NCBI_TaxID=8692;
RN   [1]
RP   PROTEIN SEQUENCE, CATALYTIC ACTIVITY, COFACTOR, SUBCELLULAR LOCATION,
RP   SUBUNIT, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=21333664; DOI=10.1016/j.toxicon.2011.02.013;
RA   Vulfius C.A., Gorbacheva E.V., Starkov V.G., Osipov A.V., Kasheverov I.E.,
RA   Andreeva T.V., Astashev M.E., Tsetlin V.I., Utkin Y.N.;
RT   "An unusual phospholipase A(2) from puff adder Bitis arietans venom-a novel
RT   blocker of nicotinic acetylcholine receptors.";
RL   Toxicon 57:787-793(2011).
CC   -!- FUNCTION: Snake venom phospholipase A2 (PLA2) that is the first
CC       competitive blocker of nicotinic acetylcholine receptors (nAChRs)
CC       (PubMed:21333664). Competes with alpha-bungarotoxin for binding to
CC       nAChRs and acetylcholine binding proteins (AChBPs) and blocks
CC       acetylcholine-elicited current (PubMed:21333664). PLA2 catalyzes the
CC       calcium-dependent hydrolysis of the 2-acyl groups in 3-sn-
CC       phosphoglycerides (PubMed:21333664). {ECO:0000269|PubMed:21333664}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 1-acyl-sn-
CC         glycero-3-phosphocholine + a fatty acid + H(+); Xref=Rhea:RHEA:15801,
CC         ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:28868,
CC         ChEBI:CHEBI:57643, ChEBI:CHEBI:58168; EC=3.1.1.4;
CC         Evidence={ECO:0000269|PubMed:21333664};
CC   -!- COFACTOR:
CC       Name=Ca(2+); Xref=ChEBI:CHEBI:29108;
CC         Evidence={ECO:0000269|PubMed:21333664};
CC       Note=Binds 1 Ca(2+) ion. {ECO:0000269|PubMed:21333664};
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       Kinetic parameters:
CC         Vmax=1.95 mmol/min/umol enzyme {ECO:0000269|PubMed:21333664};
CC   -!- SUBUNIT: Monomer. {ECO:0000269|PubMed:21333664}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:21333664}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:21333664}.
CC   -!- PTM: Contains 14 disulfide bonds. {ECO:0000269|PubMed:21333664}.
CC   -!- MASS SPECTROMETRY: Mass=27385; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:21333664};
CC   -!- MISCELLANEOUS: Accounts for only about 0.5% of dry venom mass.
CC       {ECO:0000305|PubMed:21333664}.
CC   -!- MISCELLANEOUS: The molecular mass and the number of disulfide bonds are
CC       two times greater than that observed for other snake venom PLA2
CC       molecules. This finding suggests that bitanarin may contain 2 repeats
CC       of the PLA2 sequence in a single polypeptide chain (PubMed:21333664).
CC       {ECO:0000305|PubMed:21333664}.
CC   -!- SIMILARITY: Belongs to the phospholipase A2 family. Group II subfamily.
CC       {ECO:0000305}.
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DR   AlphaFoldDB; P0DKT6; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0004623; F:phospholipase A2 activity; IEA:UniProtKB-EC.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Hydrolase; Neurotoxin;
KW   Postsynaptic neurotoxin; Secreted; Toxin.
FT   CHAIN           1..>35
FT                   /note="Phospholipase A2 bitanarin"
FT                   /evidence="ECO:0000269|PubMed:21333664"
FT                   /id="PRO_0000420852"
FT   DISULFID        27..?
FT                   /evidence="ECO:0000250"
FT   DISULFID        29..?
FT                   /evidence="ECO:0000250"
FT   NON_CONS        20..21
FT                   /evidence="ECO:0000305"
FT   NON_TER         35
SQ   SEQUENCE   35 AA;  3792 MW;  36A49E071007B321 CRC64;
     SLIEFGKMIT EETNRPVFPY EATIVVCDCG NGNGS