ID   PA2B2_BUNCE             Reviewed;         147 AA.
AC   Q8QFW3;
DT   19-SEP-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-2002, sequence version 1.
DT   03-AUG-2022, entry version 82.
DE   RecName: Full=Basic phospholipase A2 beta-bungarotoxin A2 chain;
DE            Short=Beta-BuTX A2 chain;
DE            Short=svPLA2;
DE            EC=3.1.1.4;
DE   AltName: Full=Phosphatidylcholine 2-acylhydrolase;
DE   Flags: Precursor;
OS   Bungarus caeruleus (Indian krait).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Bungarinae; Bungarus.
OX   NCBI_TaxID=132961;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RA   Paramasivam M., Srinivasan A., Singh T.P.;
RT   "Bungarus caeruleus mRNA for phospholipase A2, beta bungarotoxin A2 chain
RT   complete coding region.";
RL   Submitted (FEB-2002) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Snake venom phospholipase A2 (PLA2) that inhibits
CC       neuromuscular transmission by blocking acetylcholine release from the
CC       nerve termini. PLA2 catalyzes the calcium-dependent hydrolysis of the
CC       2-acyl groups in 3-sn-phosphoglycerides (By similarity). {ECO:0000250}.
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:0000255|PROSITE-ProRule:PRU10035, ECO:0000255|PROSITE-
CC         ProRule:PRU10036};
CC   -!- COFACTOR:
CC       Name=Ca(2+); Xref=ChEBI:CHEBI:29108; Evidence={ECO:0000250};
CC       Note=Binds 1 Ca(2+) ion. {ECO:0000250};
CC   -!- SUBUNIT: Heterodimer; disulfide-linked. The A chains have phospholipase
CC       A2 activity and the B chains show homology with the basic protease
CC       inhibitors (By similarity). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- SIMILARITY: Belongs to the phospholipase A2 family. Group I subfamily.
CC       D49 sub-subfamily. {ECO:0000305}.
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DR   EMBL; AY081147; AAL87004.1; -; mRNA.
DR   AlphaFoldDB; Q8QFW3; -.
DR   SMR; Q8QFW3; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0005509; F:calcium ion binding; IEA:InterPro.
DR   GO; GO:0004623; F:phospholipase A2 activity; IEA:UniProtKB-EC.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   GO; GO:0050482; P:arachidonic acid secretion; IEA:InterPro.
DR   GO; GO:0016042; P:lipid catabolic process; IEA:UniProtKB-KW.
DR   GO; GO:0006644; P:phospholipid metabolic process; IEA:InterPro.
DR   CDD; cd00125; PLA2c; 1.
DR   Gene3D; 1.20.90.10; -; 1.
DR   InterPro; IPR001211; PLipase_A2.
DR   InterPro; IPR033112; PLipase_A2_Asp_AS.
DR   InterPro; IPR016090; PLipase_A2_dom.
DR   InterPro; IPR036444; PLipase_A2_dom_sf.
DR   InterPro; IPR033113; PLipase_A2_His_AS.
DR   PANTHER; PTHR11716; PTHR11716; 1.
DR   Pfam; PF00068; Phospholip_A2_1; 1.
DR   PRINTS; PR00389; PHPHLIPASEA2.
DR   SMART; SM00085; PA2c; 1.
DR   SUPFAM; SSF48619; SSF48619; 1.
DR   PROSITE; PS00119; PA2_ASP; 1.
DR   PROSITE; PS00118; PA2_HIS; 1.
PE   2: Evidence at transcript level;
KW   Calcium; Disulfide bond; Hydrolase; Lipid degradation; Lipid metabolism;
KW   Metal-binding; Neurotoxin; Presynaptic neurotoxin; Secreted; Signal; Toxin.
FT   SIGNAL          1..19
FT                   /evidence="ECO:0000255"
FT   PROPEP          20..27
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000022825"
FT   CHAIN           28..147
FT                   /note="Basic phospholipase A2 beta-bungarotoxin A2 chain"
FT                   /id="PRO_0000022826"
FT   ACT_SITE        75
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        121
FT                   /evidence="ECO:0000250"
FT   BINDING         55
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250"
FT   BINDING         57
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250"
FT   BINDING         59
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250"
FT   BINDING         76
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250"
FT   DISULFID        42
FT                   /note="Interchain (with a B chain)"
FT                   /evidence="ECO:0000250"
FT   DISULFID        54..146
FT                   /evidence="ECO:0000250"
FT   DISULFID        56..72
FT                   /evidence="ECO:0000250"
FT   DISULFID        71..127
FT                   /evidence="ECO:0000250"
FT   DISULFID        78..120
FT                   /evidence="ECO:0000250"
FT   DISULFID        88..113
FT                   /evidence="ECO:0000250"
FT   DISULFID        106..118
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   147 AA;  16120 MW;  3B72A0EEE323EADF CRC64;
     MYPAHLLVLS AVCVSLLGAA NIPPYPLNLI NFMEMIRYTI PCDKTWGHYA DYGCYCGAGG
     SGTPVDALDR CCYVHDNCYG VAENKHKCNP KTQSCSYKLT KRTIICYGAA GTCGRIVCDC
     DRTAALCFGD SEYIGAHKNI DTKRHCQ