Amino-group carrier-protein-mediated secondary metabolite biosynthesis in Streptomyces.

Amino-group carrier proteins (AmCPs) mediate the biosynthesis of lysine and arginine in some bacteria and archaea. Here we demonstrate that an uncharacterized AmCP-mediated biosynthetic system functions to biosynthesize the previously uncharacterized and nonproteinogenic amino acid (2S,6R)-diamino-(5R,7)-dihydroxy-heptanoic acid (DADH) in Streptomyces sp. SANK 60404. DADH is incorporated into a novel peptide metabolite, vazabitide A, featuring an azabicyclo-ring structure, by nonribosomal peptide synthetases and successive modification enzymes in this bacterium. As the AmCP-mediated machinery for DADH biosynthesis is widely distributed in bacteria, further analysis of uncharacterized AmCP-containing gene clusters will lead to the discovery of novel bioactive compounds and novel biosynthetic enzymes.