PA2B1_BUNMU
ID PA2B1_BUNMU Reviewed; 147 AA.
AC P00617; Q8QFN8; Q9PU95; Q9PU98;
DT 21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT 19-SEP-2002, sequence version 2.
DT 03-AUG-2022, entry version 142.
DE RecName: Full=Basic phospholipase A2 beta-bungarotoxin A1 chain;
DE Short=Beta-BuTX A1 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;
RA Chang L.-S., Chu Y.P.;
RT "Genomic organization of the genes encoding the A chains of beta-
RT bungarotoxins.";
RL Submitted (FEB-2002) to the EMBL/GenBank/DDBJ databases.
RN [2]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 10-147.
RC TISSUE=Liver;
RX PubMed=10903499; DOI=10.1046/j.1432-1327.2000.01518.x;
RA Wu P.-F., Chang L.-S.;
RT "Genetic organization of A chain and B chain of beta-bungarotoxin from
RT Taiwan banded krait (Bungarus multicinctus). A chain genes and B chain
RT genes do not share a common origin.";
RL Eur. J. Biochem. 267:4668-4675(2000).
RN [3]
RP NUCLEOTIDE SEQUENCE [MRNA] OF 11-147, AND MUTAGENESIS OF CYS-42.
RC TISSUE=Venom gland;
RX PubMed=11732693; DOI=10.1023/a:1012237005574;
RA Wu P.-F., Chang L.-S.;
RT "Expression of A chain and B chain of beta-bungarotoxin from taiwan banded
RT krait: the functional implication of the interchain disulfide bond between
RT A chain and B chain.";
RL J. Protein Chem. 20:413-421(2001).
RN [4]
RP PROTEIN SEQUENCE OF 28-147, AND SUBCELLULAR LOCATION.
RC TISSUE=Venom;
RX PubMed=624701; DOI=10.1093/oxfordjournals.jbchem.a131881;
RA Kondo K., Narita K., Lee C.-Y.;
RT "Amino acid sequences of the two polypeptide chains in beta1-bungarotoxin
RT from the venom of Bungarus multicinctus.";
RL J. Biochem. 83:101-115(1978).
RN [5]
RP PROTEIN SEQUENCE OF 28-147, SEQUENCE REVISION TO 112-114 AND 136, AND
RP SUBCELLULAR LOCATION.
RX PubMed=7096304; DOI=10.1093/oxfordjournals.jbchem.a133843;
RA Kondo K., Toda H., Narita K., Lee C.-Y.;
RT "Amino acid sequence of beta 2-bungarotoxin from Bungarus multicinctus
RT venom. The amino acid substitutions in the B chains.";
RL J. Biochem. 91:1519-1530(1982).
RN [6]
RP CHARACTERIZATION OF PHOSPHOLIPASE A2 ACTIVITY.
RX PubMed=730754; DOI=10.1093/oxfordjournals.jbchem.a132249;
RA Kondo K., Toda H., Narita K.;
RT "Characterization of phospholipase A activity of beta1-bungarotoxin from
RT Bungarus multicinctus venom. II. Identification of the histidine residue of
RT beta1-bungarotoxin modified by p-bromophenacyl bromide.";
RL J. Biochem. 84:1301-1308(1978).
RN [7]
RP CHARACTERIZATION OF PRESYNAPTIC NEUROTOXINS.
RX PubMed=303565; DOI=10.1111/j.1432-1033.1977.tb11849.x;
RA Abe T., Alema S., Miledi R.;
RT "Isolation and characterization of presynaptically acting neurotoxins from
RT the venom of Bungarus snakes.";
RL Eur. J. Biochem. 80:1-12(1977).
RN [8]
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).
RN [9]
RP X-RAY CRYSTALLOGRAPHY (2.45 ANGSTROMS) OF 28-147 IN COMPLEX WITH CALCIUM
RP ION, COFACTOR, AND DISULFIDE BONDS.
RC TISSUE=Venom;
RX PubMed=8590005; DOI=10.1016/s0969-2126(01)00246-5;
RA Kwong P.D., McDonald N.Q., Sigler P.B., Hendrickson W.A.;
RT "Structure of beta 2-bungarotoxin: potassium channel binding by Kunitz
RT modules and targeted phospholipase action.";
RL Structure 3:1109-1119(1995).
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;
CC Evidence={ECO:0000305|PubMed:8590005};
CC Note=Binds 1 Ca(2+) ion. {ECO:0000305|PubMed:8590005};
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 A1 chain is found in beta-1 and beta-2 bungarotoxins.
CC {ECO:0000269|PubMed:8590005}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:624701,
CC ECO:0000269|PubMed:7096304}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC {ECO:0000305|PubMed:624701, ECO:0000305|PubMed:7096304}.
CC -!- TOXIC DOSE: LD(50) is 0.019 mg/kg by intraperitoneal injection (beta-1
CC bungarotoxin) and LD(50) is 0.028 mg/kg (beta-2 bungarotoxin).
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; AJ431711; CAD24466.1; -; mRNA.
DR EMBL; AJ251360; CAB62164.1; -; Genomic_DNA.
DR EMBL; AJ242011; CAB62383.1; -; mRNA.
DR PDB; 1BUN; X-ray; 2.45 A; A=28-147.
DR PDBsum; 1BUN; -.
DR AlphaFoldDB; P00617; -.
DR SMR; P00617; -.
DR MINT; P00617; -.
DR EvolutionaryTrace; P00617; -.
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 3D-structure; Calcium; Direct protein sequencing; Disulfide bond;
KW Hydrolase; Lipid degradation; Lipid metabolism; Metal-binding; Neurotoxin;
KW Presynaptic neurotoxin; Secreted; Signal; Toxin.
FT SIGNAL 1..19
FT /evidence="ECO:0000255"
FT PROPEP 20..27
FT /evidence="ECO:0000269|PubMed:624701,
FT ECO:0000269|PubMed:7096304"
FT /id="PRO_0000022835"
FT CHAIN 28..147
FT /note="Basic phospholipase A2 beta-bungarotoxin A1 chain"
FT /id="PRO_0000022836"
FT ACT_SITE 75
FT /evidence="ECO:0000250|UniProtKB:P14418"
FT ACT_SITE 121
FT /evidence="ECO:0000250|UniProtKB:P14418"
FT BINDING 55
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000305|PubMed:8590005"
FT BINDING 57
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000305|PubMed:8590005"
FT BINDING 59
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000305|PubMed:8590005"
FT BINDING 76
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000305|PubMed:8590005"
FT DISULFID 42
FT /note="Interchain (with a B chain)"
FT /evidence="ECO:0000269|PubMed:8590005"
FT DISULFID 54..146
FT /evidence="ECO:0000269|PubMed:8590005,
FT ECO:0007744|PDB:1BUN"
FT DISULFID 56..72
FT /evidence="ECO:0000269|PubMed:8590005,
FT ECO:0007744|PDB:1BUN"
FT DISULFID 71..127
FT /evidence="ECO:0000269|PubMed:8590005,
FT ECO:0007744|PDB:1BUN"
FT DISULFID 78..120
FT /evidence="ECO:0000269|PubMed:8590005,
FT ECO:0007744|PDB:1BUN"
FT DISULFID 88..113
FT /evidence="ECO:0000269|PubMed:8590005,
FT ECO:0007744|PDB:1BUN"
FT DISULFID 106..118
FT /evidence="ECO:0000269|PubMed:8590005,
FT ECO:0007744|PDB:1BUN"
FT VARIANT 116
FT /note="I -> V (in 20% of the molecules)"
FT MUTAGEN 42
FT /note="C->S: Loss of PA2 activity. No loss in Ca(2+)-
FT binding ability. Weak loss in folding."
FT /evidence="ECO:0000269|PubMed:11732693"
FT CONFLICT 10
FT /note="S -> L (in Ref. 2; CAB62164)"
FT /evidence="ECO:0000305"
FT CONFLICT 93..94
FT /note="QS -> SQ (in Ref. 4; AA sequence and 5; AA
FT sequence)"
FT /evidence="ECO:0000305"
FT CONFLICT 130..132
FT /note="NSE -> QSD (in Ref. 4; AA sequence and 5; AA
FT sequence)"
FT /evidence="ECO:0000305"
FT HELIX 29..37
FT /evidence="ECO:0007829|PDB:1BUN"
FT HELIX 47..50
FT /evidence="ECO:0007829|PDB:1BUN"
FT TURN 53..55
FT /evidence="ECO:0007829|PDB:1BUN"
FT STRAND 56..58
FT /evidence="ECO:0007829|PDB:1BUN"
FT HELIX 67..83
FT /evidence="ECO:0007829|PDB:1BUN"
FT TURN 84..86
FT /evidence="ECO:0007829|PDB:1BUN"
FT TURN 90..92
FT /evidence="ECO:0007829|PDB:1BUN"
FT STRAND 97..100
FT /evidence="ECO:0007829|PDB:1BUN"
FT STRAND 103..106
FT /evidence="ECO:0007829|PDB:1BUN"
FT HELIX 113..130
FT /evidence="ECO:0007829|PDB:1BUN"
FT HELIX 135..137
FT /evidence="ECO:0007829|PDB:1BUN"
FT HELIX 142..145
FT /evidence="ECO:0007829|PDB:1BUN"
SQ SEQUENCE 147 AA; 16220 MW; 12109A187E20C7F6 CRC64;
MNPAHLLVLS AVCVSLLGAA NIPPHPLNLI NFMEMIRYTI PCEKTWGEYA DYGCYCGAGG
SGRPIDALDR CCYVHDNCYG DAEKKHKCNP KTQSYSYKLT KRTIICYGAA GTCGRIVCDC
DRTAALCFGN SEYIEGHKNI DTARFCQ
