poliketide

Polyketides are a large and structurally diverse class of naturally occurring organic compounds produced by a variety of organisms, including bacteria, fungi, plants, and marine animals. They are synthesized by large multienzyme complexes called polyketide synthases (PKSs). These enzymes function similarly to fatty acid synthases, but with greater flexibility in their substrate selection and processing steps, leading to a much wider array of final products.

The biosynthesis of polyketides involves the sequential condensation of simple acyl-CoA or malonyl-CoA extender units. These units are added to a growing polyketide chain, which is then modified through a series of enzymatic reactions such as reduction, dehydration, and cyclization. The specific sequence of these steps, dictated by the modular nature of the PKS enzymes, determines the final carbon backbone and functional groups of the polyketide.

Polyketides exhibit a remarkable range of biological activities and are a significant source of pharmaceuticals. Examples include antibiotics like erythromycin and tetracycline, antifungals such as amphotericin B, immunosuppressants like tacrolimus, and anticancer agents like doxorubicin. Their structural complexity and diverse bioactivities make them important targets for drug discovery and synthetic chemistry. Research into polyketide biosynthesis and engineering aims to unlock new therapeutic agents and optimize the production of existing ones.