Reviewed, UniProtKB/Swiss-Prot P55963 (CXA4A_CONPU)

Names and origin

Protein names	Recommended name:     Alpha-A conotoxin PIVA
Organism	Conus purpurascens (Purple cone)
Taxonomic identifier	41690 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Mollusca › Gastropoda › Orthogastropoda › Apogastropoda › Caenogastropoda › Sorbeoconcha › Hypsogastropoda › Neogastropoda › Conoidea › Conidae › Conus

Protein attributes

Sequence length	25 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Alpha-A-long conotoxins act on postsynaptic membranes, they bind with high affinity to both fetal (alpha-1/beta-1/epsilon/delta subunits) and adult (alpha-1/beta-1/gamma/delta subunits) mammalian muscle nicotinic acetylcholine receptors (nAChR) and thus inhibit them. This toxin has higher affinity for the adult subtype (IC50=2.3 nM) of the receptor than for the fetal subtype (IC50=22 nM). Ref.2
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom duct.
Sequence similarities	Belongs to the conotoxin A superfamily. Alpha-A-type family. Alpha-A-long subfamily.

Ontologies

Keywords
Cellular component	Secreted
Molecular function	Acetylcholine receptor inhibitor Neurotoxin Postsynaptic neurotoxin Toxin
PTM	Amidation Disulfide bond Hydroxylation
Technical term	3D-structure Direct protein sequencing
Gene Ontology (GO)
Biological process	pathogenesis Inferred from electronic annotation. Source: UniProtKB-KW synaptic transmission Inferred from electronic annotation. Source: UniProtKB-KW
Cellular component	extracellular region Inferred from electronic annotation. Source: UniProtKB-SubCell postsynaptic membrane Inferred from electronic annotation. Source: UniProtKB-KW
Molecular function	acetylcholine receptor inhibitor activity Inferred from electronic annotation. Source: UniProtKB-KW
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Peptide

1 – 25

25

Alpha-A conotoxin PIVA

PRO_0000044466

Amino acid modifications

Modified residue

7

1

4-hydroxyproline; partial

Modified residue

13

1

4-hydroxyproline; partial

Modified residue

20

1

4-hydroxyproline Ref.1

Modified residue

25

1

Glutamine amide

Disulfide bond

2 ↔ 16

Ref.3 Ref.1

Disulfide bond

3 ↔ 11

Ref.3 Ref.1

Disulfide bond

14 ↔ 23

Ref.3 Ref.1

Secondary structure

1

.

.

.

.

.

25

Helix Strand Turn

Details...

Turn

13 – 15

3

Helix

21 – 23

3

Sequences

	Sequence		Length	Mass (Da)
	P55963-1 [UniParc]. Last modified November 1, 1997. Version 1. Checksum: 9E2147898D697640	FASTA	25	2,608
	10 20 GCCGSYPNAA CHPCSCKDRP SYCGQ

References

[1]	"A new family of Conus peptides targeted to the nicotinic acetylcholine receptor." Hopkins C., Grilley M., Miller C., Shon K.-J., Cruz L.J., Gray W.R., Dykert J., Rivier J.E., Yoshikami D., Olivera B.M. J. Biol. Chem. 270:22361-22367(1995) [PubMed: 7673220] [Abstract] Cited for: PROTEIN SEQUENCE. Tissue: Venom.
[2]	"Definition and characterization of the short alphaA-conotoxins: a single residue determines dissociation kinetics from the fetal muscle nicotinic acetylcholine receptor." Teichert R.W., Lopez-Vera E., Gulyas J., Watkins M., Rivier J., Olivera B.M. Biochemistry 45:1304-1312(2006) [PubMed: 16430227] [Abstract] Cited for: SYNTHESIS, FUNCTION.
[3]	"NMR structure determination of a novel conotoxin, [Pro 7,13] alpha A-conotoxin PIVA." Han K.-H., Hwang K.-J., Kim S.-M., Kim S.-K., Gray W.R., Olivera B.M., Rivier J.E., Shon K.-J. Biochemistry 36:1669-1677(1997) [PubMed: 9048550] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.

Cross-references

Sequence databases

PIR

A58647.

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1P1P	NMR	-	A	1-25	[»]

ModBase

Search...

Family and domain databases

InterPro

IPR012498. Toxin_14.
[Graphical view]

Pfam

PF07829. Toxin_14. 1 hit.
[Graphical view]

ProtoNet

Search...

Entry information

Entry name

CXA4A_CONPU

Accession

Primary (citable) accession number: P55963

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 1, 1997
Last sequence update:	November 1, 1997
Last modified:	June 16, 2009
This is version 52 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)