Reviewed, UniProtKB/Swiss-Prot P14418 (PA21B_AGKHP)

Names and origin

Protein names	Recommended name:     Phospholipase A2, acidic     EC=3.1.1.4 Alternative name(s):     Phosphatidylcholine 2-acylhydrolase     APLA2
Organism	Agkistrodon halys pallas (Chinese water mocassin) (Gloydius halys pallas)
Taxonomic identifier	8714 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Lepidosauria › Squamata › Scleroglossa › Serpentes › Colubroidea › Viperidae › Crotalinae › Gloydius

Protein attributes

Sequence length	124 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
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. Acts in vivo as an anti-thrombotic agent. Like most other acidic phospholipases, this protein is not neurotoxic.
Catalytic activity	Phosphatidylcholine + H2O = 1-acylglycerophosphocholine + a carboxylate.
Cofactor	Binds 1 calcium ion per subunit.
Subunit structure	Monomer.
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Pharmaceutical use	The venom of this snake has been orally administered to patients in China for about 2000 years, mostly to treat thrombotic diseases.
Sequence similarities	Belongs to the phospholipase A2 family. Group II subfamily.
Mass spectrometry	Molecular mass is 13962 Da from positions 1 - 124. Determined by ESI. Ref.2

Ontologies

Keywords
Biological process	Lipid degradation
Cellular component	Secreted
Ligand	Calcium Metal-binding
Molecular function	Hydrolase
PTM	Disulfide bond
Technical term	3D-structure Direct protein sequencing Pharmaceutical
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	extracellular region Inferred from electronic annotation. Source: UniProtKB-SubCell
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 – 124

124

Phospholipase A2, acidic

PRO_0000161597

Sites

Active site

47

1

Ref.3

Active site

89

1

Ref.3

Metal binding

27

1

Calcium; via carbonyl oxygen

Metal binding

29

1

Calcium; via carbonyl oxygen

Metal binding

31

1

Calcium; via carbonyl oxygen

Metal binding

48

1

Calcium

Amino acid modifications

Disulfide bond

26 ↔ 116

Ref.3 Ref.4

Disulfide bond

28 ↔ 44

Ref.3 Ref.4

Disulfide bond

43 ↔ 95

Ref.3 Ref.4

Disulfide bond

49 ↔ 124

Ref.3 Ref.4

Disulfide bond

50 ↔ 88

Ref.3 Ref.4

Disulfide bond

57 ↔ 81

Ref.3 Ref.4

Disulfide bond

75 ↔ 86

Ref.3 Ref.4

Experimental info

Sequence conflict

101 – 102

2

TL → NT AA sequence Ref.2

Secondary structure

1

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

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.

.

.

.

.

.

124

Helix Strand Turn

Details...

Helix

2 – 13

12

Helix

17 – 20

4

Beta strand

21 – 24

4

Turn

25 – 27

3

Beta strand

28 – 31

4

Helix

39 – 52

14

Turn

59 – 61

3

Beta strand

65 – 69

5

Beta strand

72 – 78

7

Helix

80 – 98

19

Helix

99 – 102

4

Helix

105 – 108

4

Helix

113 – 115

3

Helix

118 – 120

3

Sequences

	Sequence		Length	Mass (Da)
	P14418-1 [UniParc]. Last modified January 1, 1990. Version 1. Checksum: 34BE769D31A45D26	FASTA	124	13,974
	10 20 30 40 50 60 SLIQFETLIM KVAKKSGMFW YSNYGCYCGW GGQGRPQDAT DRCCFVHDCC YGKVTGCDPK 70 80 90 100 110 120 MDVYSFSEEN GDIVCGGDDP CKKEICECDR AAAICFRDNL TLYNDKKYWA FGAKNCPQEE SEPC

References

[1]	"Characterization of the structure and function of three phospholipases A2 from the venom of Agkistrodon halys pallas." Chen Y.-C., Maraganore J.M., Reardon I., Heinrikson R.L. Toxicon 25:401-409(1987) [PubMed: 3617077] [Abstract] Cited for: PROTEIN SEQUENCE. Tissue: Venom.
[2]	"Bioassay-directed purification of an acidic phospholipase A(2) from Agkistrodon halys pallas venom." Wang Y., Cui G., Zhao M., Yang J., Wang C., Giese R.W., Peng S. Toxicon 51:1131-1139(2008) [PubMed: 18456297] [Abstract] Cited for: PROTEIN SEQUENCE OF 1-114, FUNCTION, BIOASSAY, MASS SPECTROMETRY. Tissue: Venom.
[3]	"Crystal structure of an acidic phospholipase A2 from the venom of Agkistrodon halys pallas at 2.0-A resolution." Wang X.-Q., Yang J., Gui L.-L., Lin Z.-J., Chen Y.-C., Zhou Y.-C. J. Mol. Biol. 255:669-676(1996) [PubMed: 8636969] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS), ACTIVE SITE, METAL-BINDING SITES, DISULFIDE BONDS. Tissue: Venom.
[4]	"Structure of a snake venom phospholipase A2 modified by p-bromo-phenacyl-bromide." Zhao H., Tang L., Wang X., Zhou Y., Lin Z. Toxicon 36:875-886(1998) [PubMed: 9663694] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS), METAL-BINDING SITES, DISULFIDE BONDS. Tissue: Venom.

Cross-references

Sequence databases

PIR

A26535.

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1BK9	X-ray	2.00	A	1-124	[»]
1PSJ	X-ray	2.00	A	1-124	[»]

ModBase

Search...

Phylogenomic databases

HOVERGEN

P14418.

Enzyme and pathway databases

BRENDA

3.1.1.4. 95980.

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_AGKHP

Accession

Primary (citable) accession number: P14418

Entry history

Integrated into UniProtKB/Swiss-Prot:	January 1, 1990
Last sequence update:	January 1, 1990
Last modified:	June 16, 2009
This is version 83 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)