Molecular cloning and nucleotide sequence analysis of a cDNA encoding the main beta-neurotoxin from the venom of the South American scorpion Tityus serrulatus.
A cDNA encoding the main Tityus serrulatus beta-neurotoxin was isolated from a venom gland cDNA library by using an oligonucleotide probe. The amino acid sequence deduced from the cDNA nucleotide sequence indicated that the toxin is the processed product of a precursor containing: (i) a signal peptide of 20 residues; (ii) the amino acid sequence of the mature toxin; and (iii) an extra Gly-Lys-Lys tail at the C-terminal end before the termination codon. Thus, in addition to the removal of the signal peptide by a signal peptidase, the generation of the mature toxin requires both a post-translational cleavage by a carboxypeptidase specific for basic residues and the action of an alpha-amidating enzyme. These results also show that the biosynthetic pathway for beta-toxins of 'New World' scorpion venoms is similar to that already described for alpha-toxins of 'Old World' scorpion venoms.
Martin-Eauclaire
M F
MF
Centre National de la Recherche Scientifique, URA 1455, Université d'Aix-Marseille II, Faculté de Medecine Secteur Nord, Marseille, France.
Céard
B
B
Ribeiro
A M
AM
Diniz
C R
CR
Rochat
H
H
Bougis
P E
PE
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D011487:Protein Conformation; D011498:Protein Precursors / Q000737:chemistry; D021382:Protein Sorting Signals / Q000737:chemistry; D012604:Scorpion Venoms / Q000737:chemistry / Q000235:genetics*
D015345:Oligonucleotide Probes; D011498:Protein Precursors; D021382:Protein Sorting Signals; D012604:Scorpion Venoms; C042143:toxin VII; D004247:DNA