title: Sodium channel modulating activity in a delta-conotoxin from an Indian marine snail.
abstract: A 26 residue peptide (Am 2766) with the sequence CKQAGESCDIFSQNCCVG-TCAFICIE-NH(2) has been isolated and purified from the venom of the molluscivorous snail, Conus amadis, collected off the southeastern coast of India. Chemical modification and mass spectrometric studies establish that Am 2766 has three disulfide bridges. C-terminal amidation has been demonstrated by mass measurements on the C-terminal fragments obtained by proteolysis. Sequence alignments establish that Am 2766 belongs to the delta-conotoxin family. Am 2766 inhibits the decay of the sodium current in brain rNav1.2a voltage-gated Na(+) channel, stably expressed in Chinese hamster ovary cells. Unlike delta-conotoxins have previously been isolated from molluscivorous snails, Am 2766 inhibits inactivation of mammalian sodium channels.
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.
authors.forename: S
authors.initials: S
authors.lastname: Sudarslal
authors.forename: Sriparna
authors.initials: S
authors.lastname: Majumdar
authors.forename: P
authors.initials: P
authors.lastname: Ramasamy
authors.forename: Ritu
authors.initials: R
authors.lastname: Dhawan
authors.forename: Prajna P
authors.initials: PP
authors.lastname: Pal
authors.forename: Mani
authors.initials: M
authors.lastname: Ramaswami
authors.forename: Anil K
authors.initials: AK
authors.lastname: Lala
authors.forename: S K
authors.initials: SK
authors.lastname: Sikdar
authors.forename: Siddhartha P
authors.initials: SP
authors.lastname: Sarma
authors.forename: K S
authors.initials: KS
authors.lastname: Krishnan
authors.forename: P
authors.initials: P
authors.lastname: Balaram
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D020916:Conotoxins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D004594:Electrophysiology; D007194:India; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017386:Sequence Homology, Amino Acid; D012908:Snails / Q000737:chemistry*; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D020916:Conotoxins; D015222:Sodium Channels; D012964:Sodium