cDNA cloning of two A-superfamily conotoxins from Conus striatus.
The full-length cDNAs of two A-superfamily conotoxins, kappaA-SIVA and alpha-SII, were respectively cloned and sequenced from Conus striatus using 3' RACE and 5' RACE. The cDNA of kappaA-SIVA encodes a precursor of 68 residues, including a signal peptide of 21 residues, a pro-peptide of 17 residues, and a mature peptide of 30 residues with an additional residue Gly which is prerequisite for the amidation of the preceding C-terminal Cys. The cDNA-deduced sequence of alpha-SII is composed of a signal peptide of 21 residues, a pro-peptide of 29 residues, a mature peptide of 19 residues and three additional residues Arg-Thr-Ile at the C-terminus. This tripeptide might be cleaved off by proteolytic processing. Although these two conotoxins belong to different families and target voltage-gated potassium channel and nicotinic acetylcholine receptor, respectively, they share the same signal sequence, and both are processed at the common signal site -X-Arg- immediately before the mature peptide sequences. The length of 3' untranslational region of alpha-conotoxin SII was extraordinarily large about 10 times longer than that of kappaA-SIVA with 770 and 75 bp, respectively. The elucidated cDNAs of these two toxins will facilitate a better understanding of the process of their post-translational modifications.
Key Laboratory of Proteomics, Shanghai Institute of Biochemistry and Cell Biology, Shanghai Institute of Biological Sciences, The Chinese Academy of Sciences, Shanghai 200031, China.
Cheng-Zhong
CZ
Wang
Hui
H
Jiang
Zhou-Luo
ZL
Ou
Ji-Sheng
JS
Chen
Cheng-Wu
CW
Chi
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D008974:Mollusca / Q000235:genetics*; D008978:Mollusk Venoms / Q000145:classification / Q000235:genetics*
D018076:DNA, Complementary; D008978:Mollusk Venoms