8.B.34. The Sigma-Conotoxin (Sigma-Conotoxin) Family Sigma-conotoxins bind and inhibit serotonin-gated ion channels. These peptides selectively and reversibly inhibit 5-hydroxytryptamine 3 receptors (HTR3A) through competitive antagonism (IC₅₀=53-86.8 nM) (England et al. 1998).
This family belongs to the Conotoxin Superfamily.
References:
England, L.J., J. Imperial, R. Jacobsen, A.G. Craig, J. Gulyas, M. Akhtar, J. Rivier, D. Julius, and B.M. Olivera. (1998). Inactivation of a serotonin-gated ion channel by a polypeptide toxin from marine snails. Science 281: 575-578.
Examples:
TC#	Name	Organismal Type	Example
8.B.34.1.1	Sigma-conotoxin of 88 aas and 1 TMS. Sigma-conotoxins bind and inhibit serotonin-gated ion channels. This peptide selectively and reversibly inhibits 5-hydroxytryptamine 3 receptor (HTR3A) through competitive antagonism (IC₅₀=53-86.8 nM) (England et al. 1998).		σ-Conotoxin of Conus geographus (Geography cone) (Nubecula geographus)

8.B.34.1.2	Conotoxin Di8.1 of 77 aas and 1 N-terminal TMS.		*Conotoxin Di8.1 of Conus distans* (Distant cone)**

8.B.34.1.3	Conotoxin of 84 aas and 1 N-terminal TMS		*Conotoxin of Conus betulinus* (Beech cone)**

8.B.34.1.4	Conotoxin Im030 of 85 aas and 1 N-terminal TMS.		*Conotoxin Im030 of Conus imperialis* (Imperial cone)**

8.B.34.1.5	Uncharacterized protein of 124 aas and 1 N-terminal TMS.		UP of Fragilariopsis cylindrus

8.B.34.1.6	Uncharacterized protein of 99 aas and 1 N-terminal TMS.		UP of Oryzias javanicus

Examples:
TC#	Name	Organismal Type	Example