title: Collision induced dissociation-based characterization of nucleotide peptides: fragmentation patterns of microcin C7-C51, an antimicrobial peptide produced by Escherichia coli.
abstract: Covalent protein-nucleic acid conjugates form an original class of compounds that occur in nature or can be generated in vitro through cross-linking to investigate domains involved in protein/nucleic acid interactions. Their mass spectrometry fragmentation patterns are poorly characterized. We have used electrospray-ionization mass spectrometry (ESI-MS) combined with collision-induced dissociation (CID) to characterize microcin C7-C51, an antimicrobial nucleotide peptide that targets aspartyl-tRNA synthetase and inhibits translation. The fragments of microcin C7-C51 were analyzed in positive- and negative-ion modes and compared with those of the corresponding unmodified heptapeptide and to the derived aspartyl-adenylate. The positive- and negative-ion mode fragments of microcin C7-C51 provided information on both the nucleotide and peptide moieties. Accurate mass measurement obtained using an LTQ Orbitrap instrument was a key factor for a comprehensive interpretation of the fragments. The experimental results obtained permitted the proposal of stepwise fragmentation pathways involving ion-dipole complexes. The data provide a better understanding of nucleotide peptide fragmentation in the gas phase.
authors.affiliation: Muséum national d'Histoire naturelle, Laboratoire de Chimie et Biochimie des Substances Naturelles, Paris, France.
authors.forename: Vanessa W
authors.initials: VW
authors.lastname: Petit
authors.forename: Séverine
authors.initials: S
authors.lastname: Zirah
authors.forename: Sylvie
authors.initials: S
authors.lastname: Rebuffat
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Tabet
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D001430:Bacteriocins / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D009711:Nucleotides / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D009711:Nucleotides; D010455:Peptides; C020411:microcin