Identification and Heterologous Production of a Benzoyl-Primed Tricarboxylic Acid Polyketide Intermediate from the Zaragozic Acid A Biosynthetic Pathway.

Zaragozic acid A (1) is a potent cholesterol lowering, polyketide natural product made by various filamentous fungi. The reconstitution of enzymes responsible for the initial steps of the biosynthetic pathway of 1 is accomplished using an engineered fungal heterologous host. These initial steps feature the priming of a benzoic acid starter unit onto a highly reducing polyketide synthase (HRPKS), followed by oxaloacetate extension and product release to generate a tricarboxylic acid containing product 2. The reconstitution studies demonstrated that only three enzymes, HRPKS, citrate synthase, and hydrolase, are needed in A. nidulans to produce the structurally complex product.