title: An O-conotoxin from the vermivorous Conus spurius active on mice and mollusks.
abstract: Here, we report the purification, amino acid sequence and a preliminary biological characterization of a peptide, sr7a, from the venom of Conus spurius, a vermivorous species collected in the Yucatan Channel, Mexico. The peptide consists of 32 amino acid residues (CLQFGSTCFLGDDDICCSGECFYSGGTFGICS&; &, amidated C-terminus) and contains six cysteines arranged in the pattern (C-C-CC-C-C) that characterizes the O-superfamily of conotoxins. This superfamily includes several pharmacological families (omega-, kappa-, muO-, delta- and gamma-conotoxins) that target Ca(2+), K(+), Na(+) and pacemaker voltage-gated ion channels. Compared with other O-conotoxins that were purified from venoms, this peptide displays sequence similarity with omega-SVIA (from Conus striatus), delta-TxVIA/B (from Conus textile), omega-CVID (from Conus catus) and kappa-PVIIA (from Conus purpurascens). At a dose of 250 pmol, peptide sr7a elicited hyperactivity when injected intracranially into mice and produced paralysis when injected into the pedal muscle of freshwater snails, Pomacea paludosa, but it had no apparent effect after intramuscular injection into the limpet Patella opea or the freshwater fish Lebistes reticulatus.
authors.affiliation: Laboratorio de Neurofarmacología Marina, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, México.
authors.forename: Karen S
authors.initials: KS
authors.lastname: Luna-Ramírez
authors.forename: Manuel B
authors.initials: MB
authors.lastname: Aguilar
authors.forename: Andrés
authors.initials: A
authors.lastname: Falcón
authors.forename: Edgar P
authors.initials: EP
authors.lastname: Heimer de la Cotera
authors.forename: Baldomero M
authors.initials: BM
authors.lastname: Olivera
authors.forename: María
authors.initials: M
authors.lastname: Maillo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020916:Conotoxins / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D052078:Conus Snail / Q000737:chemistry*; D051379:Mice; D008969:Molecular Sequence Data; D008974:Mollusca / Q000187:drug effects*; D009135:Muscular Diseases / Q000139:chemically induced / Q000503:physiopathology; D010243:Paralysis / Q000139:chemically induced; D020539:Sequence Analysis, Protein / Q000379:methods; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D020916:Conotoxins