P00618 (PA22_BUNMU) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Phospholipase A2, beta bungarotoxin A2 chain EC=3.1.1.4 Alternative name(s): Phosphatidylcholine 2-acylhydrolase
Organism	Bungarus multicinctus (Many-banded krait)
Taxonomic identifier	8616 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Lepidosauria › Squamata › Scleroglossa › Serpentes › Colubroidea › Elapidae › Bungarinae › Bungarus

Protein attributes

Sequence length	145 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	PA2 catalyzes the calcium-dependent hydrolysis of the 2-acyl groups in 3-sn-phosphoglycerides. Inhibits neuromuscular transmission by blocking acetylcholine release from the nerve termini. Acts presynaptically.
Catalytic activity	Phosphatidylcholine + H2O = 1-acylglycerophosphocholine + a carboxylate.
Cofactor	Binds 1 calcium ion By similarity.
Subunit structure	Heterodimer; disulfide-linked. The A chains have phospholipase A2 activity and the B chains show homology with the basic protease inhibitors. The A2 chain is found in beta-3 and beta-4 bungarotoxins.
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Toxic dose	LD50 is 0.066 mg/kg by intraperitoneal injection in beta-3 bungarotoxin and 0.073 mg/kg in beta-4.
Sequence similarities	Belongs to the phospholipase A2 family. Group I subfamily.

Ontologies

Keywords
Biological process	Lipid degradation
Cellular component	Secreted
Domain	Signal
Ligand	Calcium Metal-binding
Molecular function	Hydrolase Neurotoxin Presynaptic neurotoxin Toxin
PTM	Disulfide bond
Technical term	Direct protein sequencing
Gene Ontology (GO)
Biological process	lipid catabolic process Inferred from electronic annotation. Source: UniProtKB-KW phospholipid metabolic process Inferred from electronic annotation. Source: InterPro
Cellular component	other organism presynaptic membrane Inferred from electronic annotation. Source: UniProtKB-KW
Molecular function	calcium ion binding Inferred from electronic annotation. Source: InterPro phospholipase A2 activity Inferred from electronic annotation. Source: EC
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Signal peptide	1 – 17	17	Potential
	Propeptide	18 – 25	8			PRO_0000022837
	Chain	26 – 145	120	Phospholipase A2, beta bungarotoxin A2 chain		PRO_0000022838
Sites
	Active site	73	1	By similarity
	Active site	119	1	By similarity
	Metal binding	53	1	Calcium; via carbonyl oxygen By similarity
	Metal binding	55	1	Calcium; via carbonyl oxygen By similarity
	Metal binding	57	1	Calcium; via carbonyl oxygen By similarity
	Metal binding	74	1	Calcium By similarity
Amino acid modifications
	Disulfide bond	40		Interchain (with a B chain) By similarity
	Disulfide bond	52 ↔ 144		By similarity
	Disulfide bond	54 ↔ 70		By similarity
	Disulfide bond	69 ↔ 125		By similarity
	Disulfide bond	76 ↔ 118		By similarity
	Disulfide bond	86 ↔ 111		By similarity
	Disulfide bond	104 ↔ 116		By similarity
Experimental info
	Sequence conflict	91 – 92	2	QS → SQ AA sequence Ref.2
	Sequence conflict	128	1	N → Q AA sequence Ref.2
	Sequence conflict	130	1	E → D AA sequence Ref.2

Sequences

	Sequence		Length	Mass (Da)
	P00618 [UniParc]. Last modified November 1, 1990. Version 2. Checksum: 08CD9D0E84E57581	FASTA	145	16,296
	10 20 30 40 50 60 MLIFLWCGAV CVSLLGAANI PPHPLNLINF MEMIRYTIPC EKTWGEYADY GCYCGAGGSG 70 80 90 100 110 120 RPIDALDRCC YVHDNCYGDA EKKHKCNPKT QSYSYKLTKR TIICYGAAGT CARIVCDCDR 130 140 TAALCFGNSE YIERHKNIDT KRHCR

References

[1]	"Nucleotide sequence encoding beta-bungarotoxin A2-chain from the venom glands of Bungarus multicinctus." Danse J.-M., Toussaint J.L., Kempf J. Nucleic Acids Res. 18:4609-4609(1990) [PubMed: 2388842] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Venom gland.
[2]	"Amino acid sequences of three beta-bungarotoxins (beta 3-, beta 4-, and beta 5-bungarotoxins) from Bungarus multicinctus venom. Amino acid substitutions in the A chains." Kondo K., Toda H., Narita K., Lee C.-Y. J. Biochem. 91:1531-1548(1982) [PubMed: 7096305] [Abstract] Cited for: PROTEIN SEQUENCE OF 26-145. Tissue: Venom.
[3]	"What does beta-bungarotoxin do at the neuromuscular junction?" Rowan E.G. Toxicon 39:107-118(2001) [PubMed: 10936627] [Abstract] Cited for: REVIEW.
+	Additional computationally mapped references.

Cross-references

Sequence databases
EMBL GenBank DDBJ	X53407 mRNA. Translation: CAA37483.1.
PIR	PSKFA2. S10980.
3D structure databases
ProteinModelPortal	P00618.
SMR	P00618. Positions 26-145.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Phylogenomic databases
HOVERGEN	HBG008137.
Family and domain databases
InterPro	IPR016090. PLipase_A2. IPR013090. PLipase_A2_AS. IPR001211. PLipase_A2_euk. [Graphical view]
Gene3D	G3DSA:1.20.90.10. Phospholipase_A2. 1 hit.
PANTHER	PTHR11716. Phospholipase_A2. 1 hit.
Pfam	PF00068. Phospholip_A2_1. 1 hit. [Graphical view]
PRINTS	PR00389. PHPHLIPASEA2.
SMART	SM00085. PA2c. 1 hit. [Graphical view]
SUPFAM	SSF48619. PhospholipaseA2. 1 hit.
PROSITE	PS00119. PA2_ASP. 1 hit. PS00118. PA2_HIS. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

PA22_BUNMU

Accession

Primary (citable) accession number: P00618

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	November 1, 1990
Last modified:	November 16, 2011
This is version 86 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program

Annotation program

Chordata Protein Annotation Program