Biosynthesis of the Tetramic Acids Sch210971 and Sch210972

Abstract

A biosynthetic pathway to fungal polyketide–nonribosomal peptide natural products, Sch210971 (<b>1a</b>) and Sch210972 (<b>1b</b>) from <i>Hapsidospora irregularis</i>, was characterized by reconstitution and heterologous expression in <i>Fusarium heterosporum</i>. Using genetic, biochemical, and feeding experiments, we show that the incorporated amino acid 4-hydroxyl-4-methyl glutamate (HMG) is synthesized by an aldolase, probably using pyruvate as the precursor