Biosynthesis of macrolactam antibiotics with β-amino acid polyketide starter units.

Macrolactam antibiotics incorporating β-amino acid polyketide starter units, isolated primarily from Actinomycetes species, show significant biological activities. This review provides a detailed analysis into the biosynthetic studies of vicenistatin, a macrolactam antibiotic with a 3-aminoisobutyrate starter unit, as well as biosynthetic research on related macrolactam compounds. Firstly, the elucidation of a common mechanism for the incorporation of β-amino acid starter units into the polyketide synthase (PKS) is described. Secondly, the unique biosynthetic mechanisms of the β-amino acids that are used to supply the main macrolactam biosynthetic pathways with starter units are discussed. Thirdly, some distinctive post-PKS modification mechanisms that complete macrolactam antibiotic biosynthesis are summarized. Finally, future directions for creating new macrolactam compounds through engineered biosynthesis pathways are described.