Cacaoidin, first member of the new lanthidin RiPP family

: Lantibiotics are ribosomally synthesized and post-translationally modified peptides (RiPPs) characterized by the presence of lanthionine or methyllanthionine rings and their antimicrobial activity. Cacaoidin, a novel glycosylated lantibiotic, was isolated from a Streptomyces cacaoi strain and fully characterized by NMR, mass spectrometry, chemical derivatization approaches and genome analysis. The new molecule combines outstanding structural features, such as a high number of D-amino acids, an uncommon glycosylated tyrosine residue and an unprecedented N,N -dimethyl lanthionine. This latter feature places cacaoidin within a new RiPP family located between lanthipeptides and linaridins, here termed lanthidins. Cacaoidin displayed potent antibacterial activity against Gram-positive pathogens including Clostridium difficile . The biosynthetic gene cluster showed low homology with those of other known lanthipeptides or linaridins, suggesting a new RiPP biosynthetic pathway.