Both kawaguchipeptin A and B, which only differ by post-translational modifications, have antibacterial activities, since they inhibit the growth of the Gram-positive bacterium S.aureus at a concentration of 1 ug/mL. Kawaguchipeptin A contains a D-Leu and 2 prenylated Trp, whereas kawaguchipeptin B only contains unmodified amino acids. Kawaguchipeptin A is prenylated in vivo (Ref.3). Upon expression in E.coli of the whole operon, Trp residues are prenylated by C-prenyltransferase KgpF (PubMed:26846478). Prenylation by KgpF is likely the last enzymatic step in the biosynthetic maturation of kawaguchipeptin A (PubMed:26846478). Kawaguchipeptin A (with D-Leu and prenylated Trp), in vivo. Kawaguchipeptin A (with D-Leu and prenylated Trp), when expressed in E.coli. Kawaguchipeptin B (unmodified), when expressed in E.coli. This peptide comes from bacteria isolated from a broom on Kawaguchi lake, hence its name.