Cloning of trichosanthin cDNA and its expression in Escherichia coli.

Abstract Several cDNA clones coding for trichosanthin (TCS) have been isolated from a cDNA library prepared from the poly(A) + RNA of the root tuber of Trichosanthes kirilowii Maximowicz. The nucleotide sequence codes for a protein of 289 amino acids (aa) including a putative signal peptide of 23 aa and an extra 19 aa at the C terminus; the latter two have not been found in TCS obtained from the natural product [Collins et al., J. Biol. Chem. 265 (1990) 8665–8669]. Recombinant TCS (reTCS) was synthesized in Escherichia coli , in which the cDNA without the signal sequence was expressed under the control of the trc promoter; reTCS was detected by a rabbit anti-TCS antiserum.