SI (P00001) Protein Card

General Information
Name SI
Alternative name(s) S1
Organism Conus striatus (Striated cone)
Organism region Indo-Pacific
Organism diet piscivorous
Protein Type Wild type
Protein precursor SI precursor (76)

Classification
Conopeptide class conotoxin
Gene superfamily A superfamily
Cysteine framework I
Pharmacological family alpha conotoxin

Sequence
ICCNPACGPKYSC(nh2)
Modified residues
positionsymbolname
14nh2C-term amidation
Sequence evidence protein level
Average Mass 1353.60
Monoisotopic Mass 1352.51
Isoelectric Point 9.72
Extinction Coefficient [280nm] 1490.00

Activity

IC50: Nicotinic acetylcholine receptors

TargetOrganismIC50CompetitorAgonistRef
α1β1γδM. musculus(site 1)1.3uM+/-0.410nM [125I]-BgtxGroebe,D.R. et al. (1997)
(site 2)290uM+/-11010nM [125I]-BgtxGroebe,D.R. et al. (1997)
T. californica1uM[125I]-BgtxRamilo,C. et al. (1992)
T. marmorata170nM+/-3710nM [125I]-BgtxGroebe,D.R. et al. (1997)

Synthetic variants
SI [K10H]ICCNPACGPHYSC(nh2)
SI [K10N]ICCNPACGPNYSC(nh2)
SI [P9K]ICCNPACGKKYSC(nh2)

References
Benie,A.J., Whitford,D., Hargittai,B., Barany,G. and Janes,R.W. (2000) Solution structure of alpha-conotoxin SI FEBS Lett. 476:287-295
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. and Cruz,L.J. (1992) Novel alpha- and omega-conotoxins from Conus striatus venom Biochemistry 31:9919-9926
Groebe,D.R., Gray,W.R., and Abramson,S.N. (1997) Determinants involved in the affinity of alpha-conotoxins GI and SI for the muscle subtype of nicotinic acetylcholine receptors Biochemistry 36:6469-6474
Zafaralla,G.C., Ramilo,C., Gray,W.R., Karlstrom,R., Olivera,B.M. and Cruz,L.J. (1988) Phylogenetic specificity of cholinergic ligands: alpha-conotoxin SI Biochemistry 27:7102-7105

Internal links
Protein Precursor SI precursor (76)
Nucleic acids
Structure SOLUTION STRUCTURE OF ALPHA-CONOTOXIN SI
CRYSTAL STRUCTURE OF ALPHA-CONOTOXIN SI

External links
Ncbi 1QMW_A, 1HJE_A

Tools