title: Sequence determinants governing the topology and biological activity of a lasso peptide, microcin J25.
abstract: Microcin J25 is a potent antibacterial peptide produced by Escherichia coli AY25. It displays a lasso structure, which consists of a knot involving an N-terminal macrolactam ring through which the C-terminal tail is threaded and sterically trapped. In this study, we rationally designed and performed site-specific mutations in order to pinpoint the sequence determinants of the lasso topology. Structures of the resulting variants were analysed by a combination of methods (mass spectrometry, NMR spectroscopy, enzymatic digestion), and correlated to the antibacterial activity. The selected mutations resulted in the production of branched-cyclic or lasso variants. The C-terminal residues below the ring (Tyr20, Gly21) and the size of the macrolactam ring were revealed to be critical for both the lasso scaffold and bioactivity, while shortening the loop region (Tyr9-Ser18) or extending the C-terminal tail below the ring did not alter the lasso structure, but differentially affected the antibacterial activity. These results provide new insights for the bioengineering of antibacterial agents using a lasso peptide as template.
authors.affiliation: Molécules de Communication et Adaptation des Microorganismes, UMR 7245 CNRS-Muséum National d'Histoire Naturelle, CP 54, 57 rue Cuvier, 75005 Paris, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Ducasse
authors.forename: Kok-Phen
authors.initials: KP
authors.lastname: Yan
authors.forename: Christophe
authors.initials: C
authors.lastname: Goulard
authors.forename: Alain
authors.initials: A
authors.lastname: Blond
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Li
authors.forename: Ewen
authors.initials: E
authors.lastname: Lescop
authors.forename: Eric
authors.initials: E
authors.lastname: Guittet
authors.forename: Sylvie
authors.initials: S
authors.lastname: Rebuffat
authors.forename: Séverine
authors.initials: S
authors.lastname: Zirah
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D001430:Bacteriocins / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D014644:Genetic Variation / Q000235:genetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D019779:Salmonella enterica / Q000187:drug effects*; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; C020411:microcin