CLONING AND BACTERIAL EXPRESSION OF A GENE ENCODING RIBOSOME-INACTIVATING PROTEINS, KARASURIN-A AND KARASURIN-C, FROM TRICHOSANTHES KIRILOWII VAR. JAPONICA

Abstract

A genomic DNA clone of karasurin was isolated using the polymerase chain reaction from Trichosanthes kirilowii var. japonica (Cucurbitaceae). The amino acid sequence deduced from the nucleotide sequence was consistent with previously reported sequences of karasurin-A and karasurin-C except for a putative signal peptide and extra amino acids at the C-terminus, neither of which is present in the natural protein. Recombinant karasurin was synthesized in Escherichia coli, in which the cloned karasurin gene was expressed under the control of the trc promotor.