Structural, Dynamic, and Chemical Characterization of a Novel S-Glycosylated Bacteriocin

• Published in: Biochemistry (Easton) Vol. 50; no. 14; pp. 2748 - 2755
• Main Authors: Venugopal, Hariprasad, Edwards, Patrick J. B, Schwalbe, Martin, Claridge, Jolyon K, Libich, David S, Stepper, Judith, Loo, Trevor, Patchett, Mark L, Norris, Gillian E, Pascal, Steven M
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 12-04-2011
• Subjects: Acetylglucosamine - chemistry; Bacteriocins - chemistry; Bacteriocins - metabolism; Cysteine - chemistry; Disulfides - chemistry; Glycosylation; Kinetics; Lactobacillus plantarum - metabolism; Magnetic Resonance Spectroscopy - methods; Models, Molecular; Oxygen - chemistry; Protein Conformation; Protein Processing, Post-Translational; Protein Structure, Secondary; Serine - chemistry; Sulfur - chemistry
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi200217u

Bacteriocins are bacterial peptides with specific activity against competing species. They hold great potential as natural preservatives and for their probiotic effects. We show here nuclear magnetic resonance-based evidence that glycocin F, a 43-amino acid bacteriocin from Lactobacillus plantarum, contains two β-linked N-acetylglucosamine moieties, attached via side chain linkages to a serine via oxygen, and to a cysteine via sulfur. The latter linkage is novel and has helped to establish a new type of post-translational modification, the S-linked sugar. The peptide conformation consists primarily of two α-helices held together by a pair of nested disulfide bonds. The serine-linked sugar is positioned on a short loop sequentially connecting the two helices, while the cysteine-linked sugar presents at the end of a long disordered C-terminal tail. The differing chemical and conformational stabilities of the two N-actetylglucosamine moieties provide clues about the possible mode of action of this bacteriostatic peptide.