Cloning and characterization of the cDNAs encoding Na+ channel-specific toxins 1 and 2 of the scorpion Centruroides noxius Hoffmann.
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.
Vazquez
A
A
Department of Molecular Recognition and Structural Biology, National Autonomous University of Mexico, Cuernavaca, Morelos, Mexico.
Tapia
J V
JV
Eliason
W K
WK
Martin
B M
BM
Lebreton
F
F
Delepierre
M
M
Possani
L D
LD
Becerril
B
B
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
D018076:DNA, Complementary; D009498:Neurotoxins; D012604:Scorpion Venoms; D015222:Sodium Channels