Bacteriocin ASM1 is an O/S‐diglycosylated, plasmid‐encoded homologue of glycocin F.

Here, we report on the biochemical characterization of a new glycosylated bacteriocin (glycocin), ASM1, produced by Lactobacillus plantarum A‐1 and analysis of the A‐1 bacteriocinogenic genes. ASM1 is 43 amino acids in length with Ser18‐O‐ and Cys43‐S‐linked N‐acetylglucosamine moieties that are essential for its inhibitory activity. Its only close homologue, glycocin F (GccF), has five amino acid substitutions all residing in the flexible C‐terminal 'tail' and a lower IC50 (0.9 nm) compared to that of ASM1 (1.5 nm). Asm/gcc genes share the same organization (asmH← →asmABCDE→F), and the asm genes reside on an 11 905‐bp plasmid dedicated to ASM1 production. The A‐1 genome also harbors a gene encoding a 'rare' bactofencin‐type bacteriocin. As more examples of prokaryote S‐GlcNAcylation are discovered, the functions of this modification may be understood. [ABSTRACT FROM AUTHOR]