Reviewed, UniProtKB/Swiss-Prot Q1RP78 (PA22P_VIPNI)

Names and origin

Protein names	Recommended name:     Phospholipase A2, chain HDP-2P     EC=3.1.1.4 Alternative name(s):     Phosphatidylcholine 2-acylhydrolase     Heterodimeric neurotoxic phospholipases A2 basic subunit 2
Organism	Vipera nikolskii (Nikolsky's adder)
Taxonomic identifier	110206 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Lepidosauria › Squamata › Scleroglossa › Serpentes › Colubroidea › Viperidae › Viperinae › Vipera

Protein attributes

Sequence length	138 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. The monomeric form of HDP-1P affects neuromuscular transmission acting presynaptically. It has catalytic activity, anticoagulant activity and a ADP-induced platelet aggregation activity. Ref.1 The complex of HDP-2P and its inhibitor shows the same activities as the monomer, but with a lower potency. Ref.1
Catalytic activity	Phosphatidylcholine + H2O = 1-acylglycerophosphocholine + a carboxylate.
Cofactor	Binds 1 calcium ion per subunit By similarity.
Subunit structure	Heterodimer of a toxic basic protein having phospholipase A2 activity (chain HDP-2P) and a non-toxic acidic protein functioning as its inhibitor (chain HPD-1I).
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Sequence similarities	Belongs to the phospholipase A2 family. Group II subfamily.
Mass spectrometry	Molecular mass is 13827±1 Da from positions 17 - 138. Determined by MALDI. Ref.1

Ontologies

Keywords
Cellular component	Secreted
Domain	Signal
Ligand	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: InterPro 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: 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 – 16	16	Ref.1
	Chain	17 – 138	122	Phospholipase A2, chain HDP-2P		PRO_5000079753
Sites
	Active site	63	1	By similarity
	Active site	105	1	By similarity
	Metal binding	43	1	Calcium; via carbonyl oxygen By similarity
	Metal binding	45	1	Calcium; via carbonyl oxygen By similarity
	Metal binding	47	1	Calcium; via carbonyl oxygen By similarity
	Metal binding	64	1	Calcium By similarity
Amino acid modifications
	Disulfide bond	42 ↔ 131		By similarity
	Disulfide bond	44 ↔ 60		By similarity
	Disulfide bond	59 ↔ 111		By similarity
	Disulfide bond	65 ↔ 138		By similarity
	Disulfide bond	66 ↔ 104		By similarity
	Disulfide bond	73 ↔ 97		By similarity
	Disulfide bond	91 ↔ 102		By similarity

Sequences

	Sequence		Length	Mass (Da)
	Q1RP78-1 [UniParc]. Last modified May 16, 2006. Version 1. Checksum: 28D55BD516C3EA3E	FASTA	138	15,594
	10 20 30 40 50 60 MRILWIVAVC LIGVEGNLFQ FAKMINGKLG AFSVWNYISY GCYCGWGGQG TPKDATDRCC 70 80 90 100 110 120 FVHDCCYGRV RGCNPKLAIY AYSFKKGNIV CGKNNGCLRD ICECDRVAAN CFHQNKNTYN 130 KNYRFLSSSR CRQTSEQC

References

[1]

"Heterodimeric neurotoxic phospholipases A2 -- the first proteins from venom of recently established species Vipera nikolskii: implication of venom composition in viper systematics." Ramazanova A.S., Zavada L.L., Starkov V.G., Kovyazina I.V., Subbotina T.F., Kostyukhina E.E., Dementieva I.N., Ovchinnikova T.V., Utkin Y.N. Toxicon 51:524-537(2008) [PubMed: 18083205] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 17-56; 59-71; 77-85; 87-92 AND 101-120, FUNCTION, MASS SPECTROMETRY. Tissue: Venom and Venom gland.

Cross-references

Sequence databases
EMBLGenBankDDBJ	AM238699 mRNA. Translation: CAJ87659.1.
3D structure databases
ModBase	Search...
Phylogenomic databases
HOVERGEN	Q1RP78.
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

PA22P_VIPNI

Accession

Primary (citable) accession number: Q1RP78

Entry history

Integrated into UniProtKB/Swiss-Prot:	May 5, 2009
Last sequence update:	May 16, 2006
Last modified:	June 16, 2009
This is version 24 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)