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Molecular cloning and nucleotide sequence analysis of a cDNA encoding the main β‐neurotoxin from the venom of the South American scorpion Tityus serrulatus
Author(s) -
Martin-Eauclaire M.F.,
Céard B.,
Ribeiro A.M.,
Diniz C.R.,
Rochat H.,
Bougis P.E.
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80445-m
Subject(s) - complementary dna , biology , venom , peptide sequence , signal peptide , scorpion venoms , biochemistry , nucleic acid sequence , microbiology and biotechnology , cdna library , neurotoxin , molecular cloning , peptide , scorpion toxin , toxin , amino acid , gene , scorpion
A cDNA encoding the main Tityus serrulatus β‐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 α‐amidating enzyme. These results also show that the biosynthetic pathway for β‐toxins of ‘New World’ scorpion venoms is similar to that already described for α‐toxins of ‘Old World’ scorpion venoms.