cDNA cloning of two novel T-superfamily conotoxins from Conus leopardus.
The full-length cDNAs of two novel T-superfamily conotoxins, Lp5.1 and Lp5.2, were cloned from a vermivorous cone snail Conus leopardus using 3'/5'-rapid amplification of cDNA ends. The cDNA of Lp5.1 encodes a precursor of 65 residues, including a 22-residue signal peptide, a 28-residue propeptide and a 15-residue mature peptide. Lp5.1 is processed at the common signal site-X-Arg- immediately before the mature peptide sequences. In the case of Lp5.2, the precursor includes a 25-residue signal peptide and a 43-residue sequence comprising the propeptide and mature peptide, which is probably cleaved to yield a 29-residue propeptide and a 14-residue mature toxin. Although these two conotoxins share a similar signal sequence and a conserved disulfide pattern with the known T-superfamily, the pro-region and mature peptides are of low identity, especially Lp5.2 with an identity as low as 10.7% compared with the reference Mr5.1a. The elucidated cDNAs of these two toxins will facilitate a better understanding of the species distribution, the sequence diversity of T-superfamily conotoxins, the special gene structure and the evolution of these peptides.
Chen
Wei-Hua
WH
Institute of Protein Research, Tongji University, Shanghai 200092, China.
Han
Yu-Hong
YH
Wang
Qi
Q
Miao
Xiao-Wei
XW
Ou
Ling
L
Shao
Xiao-Xia
XX
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular / Q000379:methods*; D020916:Conotoxins / Q000235:genetics*; D052078:Conus Snail / Q000737:chemistry; D018076:DNA, Complementary / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D016415:Sequence Alignment
D020916:Conotoxins; D018076:DNA, Complementary