THE BIOSYNTHESIS OF MURAYAQUINONE, A REARRANGED POLYKETIDE

Incorporations of sodium [1,2-C-13(2)]acetate and sodium [1-C-13,O-18( 2)]acetate confirmed that murayaquinone, produced by Streptomyces mura yamaensis, is a polyketide. However, the labeling patterns revealed th at a simple folding of the decaketide intermediate does not lead direc tly to the final phenanthrene skeleton. Instead a different phenanthre ne is apparently formed that undergoes an oxidative cleavage, isomeriz ation, and re-closure to a new phenanthrene skeleton. (C) 1997 Elsevie r Science Ltd.