Biosynthetic Origin of the Ansa-Structure of Ansamitocin P-3

Abstract

The biosynthetic origin of the ansa-structure of ansamitocin P-3 was investigated by feeding ¹⁴C- and ¹³C-labeled compounds. The results suggested that the ansa-structure was constructed from a long aliphatic chain composed of three C₂-units directly derived from acetate, one C₂-unit derived from metabolites of glucose and three C₃-units derived from propionate, and an aminobenzenoid nucleus derived from metabolites of glucose. Three C₁-substituents, two O-methyl and one N-methyl group in the sructure were derived from the C-2 of glycine and the S-methyl of methionine. A cyclic carbinolamide was derived from the carbamoyl of citrulline.