Glycocin F is a uniquely diglycosylated antimicrobial peptide, produced by Lactobacillus plantarum KW30, bearing a rare S-linked N-acetylglucosamine (GlcNAc) moiety in addition to an O-linked GlcNAc. It has been both structurally and biochemically characterised and shown to have a helix-loop-helix architecture, known as the Cs α/α fold, common to many unmodified peptides that function as toxins (1). The two GlcNAcs are absolutely essential for toxin activity, making it one of the few naturally occurring glycoactive antimicrobial peptides. The almost instant (< 2 minute) effect on susceptible cells at low (<2 nM) concentrations (2) poses the question of how GccF works. The fact that the antimicrobial activity is bacteriostatic instead of bactericidal suggests the mode of action is novel and could provide a significant advantage to the producer strain. We have recently shown that although the mechanism used by GccF to target susceptible cells involves a modification of that used by some class II (unmodified) bacteriocins, it is significantly different as it involves the two GlcNAc residues and probably two proteins. Knowing how the structure of the GccF molecule impacts on its activity and comparing the GccF structure with those of other glycocins has allowed us to propose a model for activity. However, pieces of the puzzle are still missing. Recent results will be presented and discussed in terms of our current results and what is known about other members of this family of antimicrobial toxins.