Genetic engineering of modular PKSs: from combinatorial biosynthesis to synthetic biology Recent advances in the elucidation of enzymatic function in natural product biosynthesis Recent advances in the biosynthesis of unusual polyketide synthase substrates Architecture of the polyketide synthase module: surprises from electron cryo-microscopy Solution structure of a nonribosomal peptide synthetase carrier protein loaded with its substrate reveals transient, well-defined contacts The structural biology of biosynthetic megaenzymes