title: cDNA cloning of two novel T-superfamily conotoxins from Conus leopardus.
abstract: 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.
authors.affiliation: Institute of Protein Research, Tongji University, Shanghai 200092, China.
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Chen
authors.forename: Yu-Hong
authors.initials: YH
authors.lastname: Han
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Miao
authors.forename: Ling
authors.initials: L
authors.lastname: Ou
authors.forename: Xiao-Xia
authors.initials: XX
authors.lastname: Shao
mesh_terms: 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
chemical_list: D020916:Conotoxins; D018076:DNA, Complementary