ID   PA22_BUNMU              Reviewed;         145 AA.
AC   P00618;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1990, sequence version 2.
DT   04-NOV-2008, entry version 73.
DE   RecName: Full=Phospholipase A2, beta bungarotoxin A2 chain;
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; Scleroglossa; Serpentes; Colubroidea;
OC   Elapidae; Bungarinae; Bungarus.
OX   NCBI_TaxID=8616;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RX   MEDLINE=90356416; 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
RT   venom glands of Bungarus multicinctus.";
RL   Nucleic Acids Res. 18:4609-4609(1990).
RN   [2]
RP   PROTEIN SEQUENCE OF 26-145.
RC   TISSUE=Venom;
RX   MEDLINE=82239270; PubMed=7096305;
RA   Kondo K., Toda H., Narita K., Lee C.-Y.;
RT   "Amino acid sequences of three beta-bungarotoxins (beta 3-, beta 4-,
RT   and 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   MEDLINE=20396379; 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: PA2 catalyzes the calcium-dependent hydrolysis of the 2-
CC       acyl groups in 3-sn-phosphoglycerides. Inhibits neuromuscular
CC       transmission by blocking acetylcholine release from the nerve
CC       termini. Acts presynaptically.
CC   -!- CATALYTIC ACTIVITY: Phosphatidylcholine + H(2)O = 1-
CC       acylglycerophosphocholine + a carboxylate.
CC   -!- COFACTOR: Binds 1 calcium ion (By similarity).
CC   -!- SUBUNIT: Heterodimer; disulfide-linked. The A chains have
CC       phospholipase A2 activity and the B chains show homology with the
CC       basic protease inhibitors. The A2 chain is found in beta-3 and
CC       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
CC       beta-3 bungarotoxin and 0.073 mg/kg in beta-4.
CC   -!- SIMILARITY: Belongs to the phospholipase A2 family. Group I
CC       subfamily.
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DR   EMBL; X53407; CAA37483.1; -; mRNA.
DR   PIR; S10980; PSKFA2.
DR   HSSP; P00617; 1BUN.
DR   SMR; P00618; 26-145.
DR   HOVERGEN; P00618; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-KW.
DR   GO; GO:0042734; C:presynaptic membrane; IEA:UniProtKB-KW.
DR   GO; GO:0009405; P:pathogenesis; IEA:UniProtKB-KW.
DR   GO; GO:0007268; P:synaptic transmission; IEA:UniProtKB-KW.
DR   InterPro; IPR016090; Phospholipase_A2.
DR   InterPro; IPR013090; Phospholipase_A2_AS.
DR   InterPro; IPR001211; Phospholipase_A2_euk.
DR   Gene3D; G3DSA:1.20.90.10; Phospholipase_A2; 1.
DR   PANTHER; PTHR11716; Phospholipase_A2; 1.
DR   Pfam; PF00068; Phospholip_A2_1; 1.
DR   PRINTS; PR00389; PHPHLIPASEA2.
DR   ProDom; PD000303; PhospholipaseA2; 1.
DR   SMART; SM00085; PA2c; 1.
DR   PROSITE; PS00119; PA2_ASP; 1.
DR   PROSITE; PS00118; PA2_HIS; 1.
PE   1: Evidence at protein level;
KW   Calcium; Direct protein sequencing; Hydrolase; Lipid degradation;
KW   Metal-binding; Neurotoxin; Presynaptic neurotoxin; Secreted; Signal;
KW   Toxin.
FT   SIGNAL        1     17       Potential.
FT   PROPEP       18     25
FT                                /FTId=PRO_0000022837.
FT   CHAIN        26    145       Phospholipase A2, beta bungarotoxin A2
FT                                chain.
FT                                /FTId=PRO_0000022838.
FT   ACT_SITE     73     73       By similarity.
FT   ACT_SITE    119    119       By similarity.
FT   METAL        53     53       Calcium; via carbonyl oxygen (By
FT                                similarity).
FT   METAL        55     55       Calcium; via carbonyl oxygen (By
FT                                similarity).
FT   METAL        57     57       Calcium; via carbonyl oxygen (By
FT                                similarity).
FT   METAL        74     74       Calcium (By similarity).
FT   DISULFID     40     40       Interchain (with a B chain) (By
FT                                similarity).
FT   DISULFID     52    144       By similarity.
FT   DISULFID     54     70       By similarity.
FT   DISULFID     69    125       By similarity.
FT   DISULFID     76    118       By similarity.
FT   DISULFID     86    111       By similarity.
FT   DISULFID    104    116       By similarity.
FT   CONFLICT     91     92       QS -> SQ (in Ref. 2; AA sequence).
FT   CONFLICT    128    128       N -> Q (in Ref. 2; AA sequence).
FT   CONFLICT    130    130       E -> D (in Ref. 2; AA sequence).
SQ   SEQUENCE   145 AA;  16296 MW;  08CD9D0E84E57581 CRC64;
     MLIFLWCGAV CVSLLGAANI PPHPLNLINF MEMIRYTIPC EKTWGEYADY GCYCGAGGSG
     RPIDALDRCC YVHDNCYGDA EKKHKCNPKT QSYSYKLTKR TIICYGAAGT CARIVCDCDR
     TAALCFGNSE YIERHKNIDT KRHCR
//