The action of the bacterial toxin, microcin B17, on DNA gyrase.
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.
Parks
William M
WM
Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK.
Bottrill
Andrew R
AR
Pierrat
Olivier A
OA
Durrant
Marcus C
MC
Maxwell
Anthony
A
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
D001426:Bacterial Proteins; D001430:Bacteriocins; C020411:microcin; D027081:DNA Gyrase