Molecular cloning and sequence analysis of cDNAs encoding a beta-toxin-like peptide and two MkTx I homologues from scorpion Buthus martensii Karsch.
Three full-length cDNAs, one encoding the precursor of a beta-toxin-like peptide (named BmKBT) and the other two encoding those of (MkTx I) homologues (named MkTx II and MkTx III, respectively), were isolated from a venom gland cDNA library of the Chinese scorpion Buthus martensii Karsch, by screening with a cDNA fragment generated by PCR. The encoded precursor of BmKBT contained 83 amino acid residues including a signal peptide of 19 residues, a mature peptide of 63 residues and an extra basic residue (Lys) which have to be removed in the processing step. The deduced amino acid sequence of BmKBT showed 52% homology to that of beta-neurotoxin TsVII isolated from scorpion Tityus serrulatus. However, the positions of disulfide bridges have a little variation between the two peptides. The precursors of MkTx II and MkTx III both contained 85 amino acid residues including a signal peptide of 19 residues, a mature peptide of 64 residues and two extra residues (Gly-Arg) which have to be removed in the processing step, too. There was high sequence similarity (90%) between the two peptides. The sequences of mature MkTx II and MkTx III were highly homologous with MkTx I isolated from scorpion Buthus martensii Karsch, both showing 90% identities.
Zeng
X C
XC
Department of Biotechnology, College of Life Sciences, Institute of Virology, Wuhan University, Wuhan 430072, People's Republic of China.
Li
W X
WX
Zhu
S Y
SY
Peng
F
F
Zhu
Z H
ZH
Liu
H
H
Mao
X
X
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D015723:Gene Library; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000032:analysis*; D016133:Polymerase Chain Reaction; D012604:Scorpion Venoms / Q000032:analysis* / Q000302:isolation & purification; D012605:Scorpions; D017422:Sequence Analysis, DNA
D018076:DNA, Complementary; C418407:KBT toxin, Buthus martensii; D009498:Neurotoxins; D012604:Scorpion Venoms; C109067:TX1 toxin, Buthus; C109068:TX2 toxin, Buthus; C418406:TX3 toxin, Buthus martensii