title: The action of the bacterial toxin, microcin B17, on DNA gyrase.
abstract: Microcin B17 (MccB17) is a peptide-based bacterial toxin that targets DNA gyrase, the bacterial enzyme that introduces supercoils into DNA. The site and mode of action of MccB17 on gyrase are unclear. We review what is currently known about MccB17-gyrase interactions and summarise approaches to understanding its mode of action that involve modification of the toxin. We describe experiments in which treatment of the toxin at high pH leads to the deamidation of two asparagine residues to aspartates. The modified toxin was found to be inactive in vivo and in vitro, suggesting that the Asn residues are essential for activity. Following on from these studies we have used molecular modelling to suggest a 3D structure for microcin B17. We discuss the implications of this model for MccB17 action and investigate the possibility that it binds metal ions.
authors.affiliation: Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK.
authors.forename: William M
authors.initials: WM
authors.lastname: Parks
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Bottrill
authors.forename: Olivier A
authors.initials: OA
authors.lastname: Pierrat
authors.forename: Marcus C
authors.initials: MC
authors.lastname: Durrant
authors.forename: Anthony
authors.initials: A
authors.lastname: Maxwell
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism; D001430:Bacteriocins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D027081:DNA Gyrase / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D001426:Bacterial Proteins; D001430:Bacteriocins; C020411:microcin; D027081:DNA Gyrase