Selective cleavages of tRNA Phe with secondary and tertiary structures by enediyne antitumor antibiotics

Abstract

Some enediyne antitumor antibiotics induce site-selective cleavages for yeast tRNA Phe with three-dimensional structure. Of special interest is the fact that tRNA Phe is specifically cleaved at the anticodon arm regions by C-1027 and esperamicin A l in the presence of Mg 2+ ions. Although neocarzinostatin strongly breaks tRNA Phe at 5′-G Pu steps in the absence of magnesium ions, its cleavage ability is completely lost in the presence of 100 μM Mg 2+ ions. Dynemicin A, which favors an intercalative binding, causes no strand scissions for the RNA with secondary and tertiary structures. This cutting of tRNA Phe may reveal that RNA as well as DNA constitutes a therapeutically relevant target for certain enediyne antitumor antibiotics.