PA2B2_BUNMU
ID PA2B2_BUNMU Reviewed; 145 AA.
AC P00618;
DT 21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1990, sequence version 2.
DT 03-AUG-2022, entry version 116.
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 multicinctus (Many-banded krait).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC Serpentes; Colubroidea; Elapidae; Bungarinae; Bungarus.
OX NCBI_TaxID=8616;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA].
RC TISSUE=Venom gland;
RX PubMed=2388842; DOI=10.1093/nar/18.15.4609;
RA Danse J.-M., Toussaint J.L., Kempf J.;
RT "Nucleotide sequence encoding beta-bungarotoxin A2-chain from the venom
RT glands of Bungarus multicinctus.";
RL Nucleic Acids Res. 18:4609-4609(1990).
RN [2]
RP PROTEIN SEQUENCE OF 26-145.
RC TISSUE=Venom;
RX PubMed=7096305; DOI=10.1093/oxfordjournals.jbchem.a133844;
RA Kondo K., Toda H., Narita K., Lee C.-Y.;
RT "Amino acid sequences of three beta-bungarotoxins (beta 3-, beta 4-, and
RT beta 5-bungarotoxins) from Bungarus multicinctus venom. Amino acid
RT substitutions in the A chains.";
RL J. Biochem. 91:1531-1548(1982).
RN [3]
RP REVIEW.
RX PubMed=10936627; DOI=10.1016/s0041-0101(00)00159-8;
RA Rowan E.G.;
RT "What does beta-bungarotoxin do at the neuromuscular junction?";
RL Toxicon 39:107-118(2001).
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.
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. The A2 chain is found in beta-3 and beta-4 bungarotoxins.
CC -!- SUBCELLULAR LOCATION: Secreted.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC -!- TOXIC DOSE: LD(50) is 0.066 mg/kg by intraperitoneal injection in beta-
CC 3 bungarotoxin and 0.073 mg/kg in beta-4.
CC -!- SIMILARITY: Belongs to the phospholipase A2 family. Group I subfamily.
CC D49 sub-subfamily. {ECO:0000305}.
CC ---------------------------------------------------------------------------
CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC ---------------------------------------------------------------------------
DR EMBL; X53407; CAA37483.1; -; mRNA.
DR PIR; S10980; PSKFA2.
DR AlphaFoldDB; P00618; -.
DR SMR; P00618; -.
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 1: Evidence at protein level;
KW Calcium; Direct protein sequencing; Disulfide bond; Hydrolase;
KW Lipid degradation; Lipid metabolism; Metal-binding; Neurotoxin;
KW Presynaptic neurotoxin; Secreted; Signal; Toxin.
FT SIGNAL 1..17
FT /evidence="ECO:0000255"
FT PROPEP 18..25
FT /evidence="ECO:0000269|PubMed:7096305"
FT /id="PRO_0000022837"
FT CHAIN 26..145
FT /note="Basic phospholipase A2 beta-bungarotoxin A2 chain"
FT /id="PRO_0000022838"
FT ACT_SITE 73
FT /evidence="ECO:0000250"
FT ACT_SITE 119
FT /evidence="ECO:0000250"
FT BINDING 53
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
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 74
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000250"
FT DISULFID 40
FT /note="Interchain (with a B chain)"
FT /evidence="ECO:0000250"
FT DISULFID 52..144
FT /evidence="ECO:0000250"
FT DISULFID 54..70
FT /evidence="ECO:0000250"
FT DISULFID 69..125
FT /evidence="ECO:0000250"
FT DISULFID 76..118
FT /evidence="ECO:0000250"
FT DISULFID 86..111
FT /evidence="ECO:0000250"
FT DISULFID 104..116
FT /evidence="ECO:0000250"
FT CONFLICT 91..92
FT /note="QS -> SQ (in Ref. 2; AA sequence)"
FT /evidence="ECO:0000305"
FT CONFLICT 128
FT /note="N -> Q (in Ref. 2; AA sequence)"
FT /evidence="ECO:0000305"
FT CONFLICT 130
FT /note="E -> D (in Ref. 2; AA sequence)"
FT /evidence="ECO:0000305"
SQ SEQUENCE 145 AA; 16296 MW; 08CD9D0E84E57581 CRC64;
MLIFLWCGAV CVSLLGAANI PPHPLNLINF MEMIRYTIPC EKTWGEYADY GCYCGAGGSG
RPIDALDRCC YVHDNCYGDA EKKHKCNPKT QSYSYKLTKR TIICYGAAGT CARIVCDCDR
TAALCFGNSE YIERHKNIDT KRHCR
