tailieunhanh - Báo cáo Y học: Thermolysin-linearized microcin J25 retains the structured core of the native macrocyclic peptide and displays antimicrobial activity

Microcin J25 (MccJ25) is the single macrocyclic antimicro-bial peptidebelonging to the ribosomally synthesizedclass of microcins that are secreted potent antibacterial activity against severalSalmonellaand Escherichiastrains and exhibited a compact three-dimen-sional structure [Blondet al. (2001) Eur. J. Biochem., 268, 2124–2133]. The molecular mechanisms involved in the biosynthesis, folding andmode of action of MccJ25 are still unknown. | Eur. J. Biochem. 269 6212-6222 2002 FEBS 2002 doi Thermolysin-linearized microcin J25 retains the structured core of the native macrocyclic peptide and displays antimicrobial activity Alain Blond1 Michel Cheminant1 Delphine Destoumieux-Garzon1 Isabelle Segalas-Milazzo2 Jean Peduzzi1 Christophe Goulard1 and Sylvie Rebuffat1 1 Laboratory of Chemistry and Biochemistry of Natural Substances Department of Regulation Development and Molecular Diversity National Museum of Natural History Paris France 2IRCOF ECOBS UMR 6014 CNRS IFRMP 23 University of Rouen France Microcin J25 MccJ25 is the single macrocyclic antimicrobial peptide belonging to the ribosomally synthesized class of microcins that are secreted by Enterobacteriaceae. It showed potent antibacterial activity against several Salmonella and Escherichia strains and exhibited a compact three-dimensional structure Blond et al. 2001 Eur. J. Biochem. 268 2124-2133 . The molecular mechanisms involved in the biosynthesis folding and mode of action of MccJ25 are still unknown. We have investigated the structure and the antimicrobial activity of thermolysin-linearized MccJ25 MccJ25-L1_21 vGiGTPISFY10GGGAGHVPEY20F as well as two synthetic analogs _2 sequence of the thermolysin-cleaved MccJ25 and sMccJ25-L12_n C-terminal sequence of the MccJ25 precursor G12GAGHVPeYf21V1GIGTPISFYG11 . The threedimensional solution structure of MccJ25-L1 21 determined by two-dimensional NMR consists of a boot-shaped hairpin-like well-defined 8-19 region flanked by disordered N and C termini. This structure is remarkably similar to that of cyclic MccJ25 and includes a short double-stranded antiparallel b-sheet 8-10 17-19 perpendicular to a loop Gly11-His16 . The thermolysin-linearized MccJ25-L1 21 had antibacterial activity against E. coli and S. enteritidis strains while both synthetic analogues lacked activity and organized structure. We show that the 8-10 17-19 b-sheet as well as the Gly11-His16 .