BIOSYNTHESIS OF LASALOCID. II

X-RAY ANALYSIS OF A NATURALLY OCCURRING ISOMER OF LASALOCID A

Abstract

A search for precursors of lasalocid A has led to the isolation and X-ray crystallographic analysis of an isomer of the antibiotic. The isomer differs from lasalocid A in both the size and absolute configuration of the terminal cyclic ether. These differences lead to speculation on the nature of cyclization mechanisms involved in the biosynthesis of lasalocid A and the other polyether antibiotics.