Biosynthesis of blasticidin S. Cell-free demonstration of n-methylation as the last step

Abstract

In continuing studies on the biosynthesis of the antifungal antibiotic blasticidin S, 1, a crude cell-free extract was prepared from Streptomyces griseochromogenes that converted demethylblasticidin S and S-adenosyl-L[ 14CH 3]methionine to 1a. Hydrolysis of 1a to blastidic acid (δ-N-methyl-L-β-arginine) and cytosinine and radiochemical analysis of the products confirmed that the former contained all the 14C radioactivity. Thus, N-methylation is the last step in the biosynthesis of 1.