title: Cloning and characterization of the cDNAs encoding Na+ channel-specific toxins 1 and 2 of the scorpion Centruroides noxius Hoffmann.
abstract: Using a cDNA library prepared from venomous glands of the Mexican scorpion Centruroides noxius Hoffmann the genes that encode toxins 1 and 2 were identified, cloned and sequenced. In view of the proposed mechanism for processing the mature peptides coded by these two genes, the corresponding peptide-toxins were sequenced de novo. Mass spectrometric and 1H-NMR analyses of the C-terminal peptide produced by enzymatic digestion of both toxins indicated that the last residue is serine-amide. Sequence comparison revealed that these two genes have a similarity of 56% and 80% at the amino acid and nucleotide levels, respectively. Small corrections to the published primary structures were introduced: Cn toxin 1 has an extra serine residue at position 65 and the residue in position 60 is a proline, while the amino acids at positions 34 and 35 of Cn 2 are, respectively, tyrosine and glycine. Sequence comparison of toxins from the genus Centruroides suggests the presence of at least three classes of distinct peptides in these venoms.
authors.affiliation: Department of Molecular Recognition and Structural Biology, National Autonomous University of Mexico, Cuernavaca, Morelos, Mexico.
authors.forename: A
authors.initials: A
authors.lastname: Vazquez
authors.forename: J V
authors.initials: JV
authors.lastname: Tapia
authors.forename: W K
authors.initials: WK
authors.lastname: Eliason
authors.forename: B M
authors.initials: BM
authors.lastname: Martin
authors.forename: F
authors.initials: F
authors.lastname: Lebreton
authors.forename: M
authors.initials: M
authors.lastname: Delepierre
authors.forename: L D
authors.initials: LD
authors.lastname: Possani
authors.forename: B
authors.initials: B
authors.lastname: Becerril
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000235:genetics*; D012604:Scorpion Venoms / Q000737:chemistry* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D015222:Sodium Channels / Q000187:drug effects* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D009498:Neurotoxins; D012604:Scorpion Venoms; D015222:Sodium Channels