Reviewed, UniProtKB/Swiss-Prot P00614 (PA21B_OXYSC)

Names and origin

Protein names	Recommended name:     Phospholipase A2, taipoxin alpha chain     EC=3.1.1.4 Alternative name(s):     Phosphatidylcholine 2-acylhydrolase
Organism	Oxyuranus scutellatus scutellatus (Australian taipan) (Coastal taipan)
Taxonomic identifier	8667 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Lepidosauria › Squamata › Scleroglossa › Serpentes › Colubroidea › Elapidae › Acanthophiinae › Oxyuranus

Protein attributes

Sequence length	119 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Taipoxin is the most potent animal toxin known. The alpha chain possesses a phospholipase activity.
Catalytic activity	Phosphatidylcholine + H2O = 1-acylglycerophosphocholine + a carboxylate.
Cofactor	Binds 1 calcium ion per subunit By similarity.
Subunit structure	Contains three non-covalently bound chains (alpha, beta, and gamma), each related to phospholipase A2.
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Toxic dose	LD50 is 0.3 mg/kg by intravenous injection.
Sequence similarities	Belongs to the phospholipase A2 family. Group I subfamily.

Ontologies

Keywords
Biological process	Lipid degradation
Cellular component	Secreted
Ligand	Calcium Metal-binding
Molecular function	Hydrolase Neurotoxin Presynaptic neurotoxin Toxin
PTM	Disulfide bond
Technical term	3D-structure Direct protein sequencing
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

Chain

1 – 119

119

Phospholipase A2, taipoxin alpha chain

PRO_0000161678

Sites

Active site

48

1

By similarity

Active site

93

1

By similarity

Metal binding

28

1

Calcium; via carbonyl oxygen By similarity

Metal binding

30

1

Calcium; via carbonyl oxygen By similarity

Metal binding

32

1

Calcium; via carbonyl oxygen By similarity

Metal binding

49

1

Calcium By similarity

Amino acid modifications

Disulfide bond

11 ↔ 72

By similarity

Disulfide bond

27 ↔ 118

By similarity

Disulfide bond

29 ↔ 45

By similarity

Disulfide bond

44 ↔ 99

By similarity

Disulfide bond

51 ↔ 92

By similarity

Disulfide bond

61 ↔ 85

By similarity

Disulfide bond

79 ↔ 90

By similarity

Secondary structure

1

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

119

Helix Strand Turn

Details...

Helix

2 – 13

12

Helix

19 – 22

4

Beta strand

23 – 25

3

Turn

26 – 28

3

Beta strand

29 – 31

3

Helix

40 – 56

17

Beta strand

70 – 72

3

Beta strand

77 – 79

3

Beta strand

81 – 83

3

Helix

84 – 102

19

Helix

107 – 109

3

Helix

114 – 117

4

Sequences

	Sequence		Length	Mass (Da)
	P00614-1 [UniParc]. Last modified July 21, 1986. Version 1. Checksum: 7FAFD5DD61105C03	FASTA	119	13,829
	10 20 30 40 50 60 NLLQFGFMIR CANRRSRPVW HYMDYGCYCG KGGSGTPVDD LDRCCQVHDE CYGEAVRRFG 70 80 90 100 110 CAPYWTLYSW KCYGKAPTCN TKTRCQRFVC RCDAKAAECF ARSPYQNSNW NINTKARCR

References

[1]	"Amino-acid sequence of the alpha-subunit of taipoxin, an extremely potent presynaptic neurotoxin from the Australian snake taipan (Oxyuranus s. scutellatus)." Lind P., Eaker D. Eur. J. Biochem. 124:441-447(1982) [PubMed: 7049694] [Abstract] Cited for: PROTEIN SEQUENCE. Tissue: Venom.

Cross-references

Sequence databases

PIR

PSOXA. A00754.

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1LX1	model	-	A	1-119	[»]

ModBase

Search...

Phylogenomic databases

HOVERGEN

P00614.

Enzyme and pathway databases

BRENDA

3.1.1.4. 293265.

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_OXYSC

Accession

Primary (citable) accession number: P00614

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	July 21, 1986
Last modified:	June 16, 2009
This is version 72 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)