Biosynthesis of Microcin E492m, a peptide toxin posttranslationally modified with a siderophore moiety

BIOL 174

Elizabeth M. Nolan, Michael A. Fischbach, and Christopher T. Walsh. Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Ave, Boston, MA 02115
Microcins are antibiotic peptides that bacteria produce and release to inhibit or kill neighboring bacteria of different species. Microcin E492m (MccE492m), secreted by K. pneumonaie and active on various species of Enterobacteriaceae, is an 84-residue peptide with a serine-rich C-terminus that is post-translationally modified with a C-glycosylated and linearized enterobactin (L-MGE) moiety (Thomas, X. et. al. J. Biol. Chem. 2004, 279, 28233-28242). The MccE492 gene cluster encodes genes mceABCDEFGHIJ, many of which are required for MccE492m assembly (Lagos, R. et. al. Mol. Microbiol. 2001, 42, 229-243). The preparation, activity and substrate specificity of glycosyltransferase MceC and esterase MceD will be presented. The protein complex MceIJ, which forms an ester linkage between serine-84 of the MccE492 peptide and the glycosyl C6 hydroxyl group of L-MGE in an ATP-dependent reaction, will also be discussed. This work was supported by NIH grant AI 47238.
 

Frontiers in Chemical Biology
5:00 PM-7:00 PM, Wednesday, August 22, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Biological Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007