P28879 (CAS2_CONST) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Alpha-conotoxin S2 Alternative name(s): Alpha-conotoxin SII
Organism	Conus striatus (Striated cone)
Taxonomic identifier	6493 [NCBI]
Taxonomic lineage	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Protostomia › Lophotrochozoa › Mollusca › Gastropoda › Caenogastropoda › Hypsogastropoda › Neogastropoda › Conoidea › Conidae › Conus

Protein attributes

Sequence length	72 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	Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them. Has no effect on the release of catecholamines evoked by nicotine. Ref.5
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom duct.
Domain	The cysteine framework is II (CCC-C-C-C).
Sequence similarities	Belongs to the conotoxin A superfamily.
Mass spectrometry	Molecular mass is 1790.3 Da from positions 51 - 69. Determined by ESI. Ref.5

Ontologies

Keywords
Cellular component	Secreted
Domain	Signal
Molecular function	Acetylcholine receptor inhibiting toxin Neurotoxin Postsynaptic neurotoxin Toxin
PTM	Disulfide bond
Technical term	Direct protein sequencing
Gene Ontology (GO)
Biological_process	pathogenesis Inferred from electronic annotation. Source: InterPro
Cellular_component	other organism 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
	Signal peptide	1 – 21	21	Potential
	Propeptide	22 – 50	29			PRO_0000034889
	Peptide	51 – 69	19	Alpha-conotoxin S2 Ref.4		PRO_0000034890
	Propeptide	70 – 72	3			PRO_0000034891
Amino acid modifications
	Disulfide bond	52 ↔ 68		Ref.5
	Disulfide bond	53 ↔ 58		Ref.5
	Disulfide bond	54 ↔ 64		Ref.5
Experimental info
	Sequence conflict	23	1	P → T no nucleotide entry Ref.1
	Sequence conflict	72	1	L → I in AAN77902. Ref.2

Sequences

	Sequence		Length	Mass (Da)
	P28879 [UniParc]. Last modified September 5, 2006. Version 3. Checksum: 521191749F4A94CF	FASTA	72	7,830
	10 20 30 40 50 60 MGMRMMFTVF LLVVLATTVV SFPSDRASDG RDDEAKDERS DMHESDRNGR GCCCNPACGP 70 NYGCGTSCSR TL

References

[1]	"Conopeptides from Conus striatus and Conus textile by cDNA cloning." Lu B.-S., Yu F., Zhao D., Huang P.-T., Huang C.-F. Peptides 20:1139-1144(1999) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Venom duct.
[2]	"cDNA cloning of two A-superfamily conotoxins from Conus striatus." Wang C.-Z., Jiang H., Ou Z.-L., Chen J.-S., Chi C.-W. Toxicon 42:613-619(2003) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Venom duct.
[3]	"The A-superfamily of conotoxins: structural and functional divergence." Santos A.D., McIntosh J.M., Hillyard D.R., Cruz L.J., Olivera B.M. J. Biol. Chem. 279:17596-17606(2004) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Venom duct.
[4]	"Novel alpha- and omega-conotoxins from Conus striatus venom." Ramilo C., Zafaralla G.C., Nadasdi L., Hammerland L.G., Yoshikami D., Gray W.R., Kristipati R., Ramachandran J., Miljanich G.P., Olivera B.M., Cruz L.J. Biochemistry 31:9919-9926(1992) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE OF 51-69, SYNTHESIS OF 51-69. Tissue: Venom.
[5]	"Optimizing the connectivity in disulfide-rich peptides: alpha-conotoxin SII as a case study." Bingham J.-P., Broxton N.M., Livett B.G., Down J.G., Jones A., Moczydlowski E.G. Anal. Biochem. 338:48-61(2005) [PubMed] [Europe PMC] [Abstract] Cited for: DISULFIDE BONDS, SYNTHESIS OF 51-69, MASS SPECTROMETRY, FUNCTION. Tissue: Venom.

Cross-references

Sequence databases
EMBL GenBank DDBJ	AY157497 mRNA. Translation: AAN77902.1.
PIR	A44379.
3D structure databases
ProteinModelPortal	P28879.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Organism-specific databases
ConoServer	3900. SII precursor. 9. SII precursor. 91. SII precursor.
Family and domain databases
InterPro	IPR009958. Conotoxin_a-typ. IPR018072. Conotoxin_a-typ_CS. [Graphical view]
Pfam	PF07365. Toxin_8. 1 hit. [Graphical view]
PROSITE	PS60014. ALPHA_CONOTOXIN. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

CAS2_CONST

Accession

Primary (citable) accession number: P28879
Secondary accession number(s): Q8I6R6

Entry history

Integrated into UniProtKB/Swiss-Prot:	December 1, 1992
Last sequence update:	September 5, 2006
Last modified:	May 1, 2013
This is version 69 of the entry and version 3 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program