Reviewed, UniProtKB/Swiss-Prot Q8QFW4 (PA21B_BUNCE)

Names and origin

Protein names	Recommended name:     Phospholipase A2, beta bungarotoxin A1 chain     EC=3.1.1.4 Alternative name(s):     Phosphatidylcholine 2-acylhydrolase
Organism	Bungarus caeruleus (Indian krait)
Taxonomic identifier	132961 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Lepidosauria › Squamata › Scleroglossa › Serpentes › Colubroidea › Elapidae › Bungarinae › Bungarus

Protein attributes

Sequence length	147 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at transcript 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 By similarity.
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 By similarity.
Subcellular location	Secreted By similarity.
Tissue specificity	Expressed by the venom gland.
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
Gene Ontology (GO)
Biological process	lipid catabolic process Inferred from electronic annotation. Source: UniProtKB-KW pathogenesis Inferred from electronic annotation. Source: UniProtKB-KW phospholipid metabolic process Inferred from electronic annotation. Source: InterPro synaptic transmission Inferred from electronic annotation. Source: UniProtKB-KW
Cellular component	extracellular region Inferred from electronic annotation. Source: UniProtKB-SubCell presynaptic membrane Inferred from electronic annotation. Source: UniProtKB-KW
Molecular function	calcium ion binding Inferred from electronic annotation. Source: UniProtKB-KW 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 – 19	19	Potential
	Propeptide	20 – 27	8	By similarity		PRO_0000022823
	Chain	28 – 147	120	Phospholipase A2, beta bungarotoxin A1 chain		PRO_0000022824
Sites
	Active site	75	1	By similarity
	Active site	121	1	By similarity
	Metal binding	55	1	Calcium; via carbonyl oxygen By similarity
	Metal binding	57	1	Calcium; via carbonyl oxygen By similarity
	Metal binding	59	1	Calcium; via carbonyl oxygen By similarity
	Metal binding	76	1	Calcium By similarity
Amino acid modifications
	Disulfide bond	42		Interchain (with a B chain) By similarity
	Disulfide bond	54 ↔ 146		By similarity
	Disulfide bond	56 ↔ 72		By similarity
	Disulfide bond	71 ↔ 127		By similarity
	Disulfide bond	78 ↔ 120		By similarity
	Disulfide bond	88 ↔ 113		By similarity
	Disulfide bond	106 ↔ 118		By similarity

Sequences

	Sequence		Length	Mass (Da)
	Q8QFW4-1 [UniParc]. Last modified June 1, 2002. Version 1. Checksum: 87DC69939719282D	FASTA	147	16,358
	10 20 30 40 50 60 MYPAHLLILS AVCVSLLGAA NIPPHPLNLI NFMNMIRYTI PCEKTWGEYT NYGCYCGAGG 70 80 90 100 110 120 SGTPIDALDR CCYVHDNCYG DAEKIHKCSP KTQSYSYKLT RRTIICYGAA GTCARIVCDC 130 140 DRTAALCFGD SEYIEGHKRI DTKRYCQ

References

[1]	"Bungarus caeruleus mRNA for beta-bungarotoxin A1 chain complete coding region." Paramasivam M., Srinivasan A., Singh T.P. Submitted (FEB-2002) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Venom gland.

Cross-references

Sequence databases
EMBLGenBankDDBJ	AY081146 mRNA. Translation: AAL87003.1.
3D structure databases
HSSP	HSSP built from PDB template 1BUN based on UniProtKB P00617.
SMR	Q8QFW4. Positions 28-147.
ModBase	Search...
Phylogenomic databases
HOVERGEN	Q8QFW4.
Enzyme and pathway databases
BRENDA	3.1.1.4. 288873.
Family and domain databases
InterPro	IPR016090. Phospholipase_A2. IPR013090. Phospholipase_A2_AS. IPR001211. Phospholipase_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.
ProDom	PD000303. PhospholipaseA2. 1 hit. [Graphical view] [Entries sharing at least one domain]
SMART	SM00085. PA2c. 1 hit. [Graphical view]
PROSITE	PS00119. PA2_ASP. 1 hit. PS00118. PA2_HIS. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

PA21B_BUNCE

Accession

Primary (citable) accession number: Q8QFW4

Entry history

Integrated into UniProtKB/Swiss-Prot:	September 19, 2002
Last sequence update:	June 1, 2002
Last modified:	June 16, 2009
This is version 45 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)