Protein–protein interactions in polyketide synthase–nonribosomal peptide synthetase hybrid assembly lines

Covering: up to early 2018 Polyketides and nonribosomal peptides are two major families of natural product with a broad range of biological activities. Polyketide synthases (PKSs) assemble small acetic acid-type acyl building blocks into polyketides through C-C bonds, and nonribosomal peptide synthetases (NRPSs) assemble amino acids into peptides through amide bonds. PKS-NRPS hybrid assembly lines build structurally complex polyketide-amino acid/peptide hybrid molecules that incorporate both acyl and aminoacyl building blocks into their products. Their combined functionalities expand the biological activities of these molecules by mixing their chemical properties. Protein-protein interactions are necessary within PKS-NRPS hybrid assembly lines to achieve accurate linkage between the PKS and NRPS systems. This review summarizes the current understanding of the roles and importance of the protein-protein interactions in various PKS-NRPS hybrid assembly lines.