Figure 1.

Structure and synthesis of the cyclodipeptide (CDP). CDP is synthesized chemically through (A) self-condensation of amino acids and (B) intramolecular cyclization of linear dipeptides. R, R1 and R2 represents a side chain, specific to each amino acid; (C) Biosynthesis of CDPs by CDP synthases (CDPSs) and subsequent modification by associated tailoring enzyme. Albonoursin [Cyclo(∆Phe-∆Leu)] (AlbC), is an antibacterial peptide produced by cyclo(l-Phe-l-Leu) and tailoring enzyme CDO (cyclicdipeptide oxidase). AlbC is a CDPS and Δ represents the dehydrated form of CDP.