title: Modes of action of tunicamycin, liposidomycin B, and mureidomycin A: inhibition of phospho-N-acetylmuramyl-pentapeptide translocase from Escherichia coli.
abstract: Using a continuous fluorescence-based enzyme assay, we have characterized the antibacterial agents tumicamycin and liposidomycin B as inhibitors of solubilized Escherichia coli phospho-N-acetylmuramyl-pentapeptide translocase. Tunicamycin exhibited reversible inhibition (Ki = 0.55 +/- 0.1 microM) which was noncompetitive with respect to the lipid acceptor substrate and competitive with respect to the fluorescent substrate analog, dansyl-UDPMurNAc-pentapeptide. Liposidomycin B exhibited slow-binding inhibition (Ki = 80 +/- 15 nM) which was competitive with respect to the lipid acceptor substrate and noncompetitive with respect to dansyl-UDPMurNAc-pentapeptide. These results provide insight into the molecular mechanisms of action of these two classes of nucleoside antibiotics.
authors.affiliation: Department of Chemistry, University of Southampton, Highfield, United Kingdom.
authors.forename: P E
authors.initials: PE
authors.lastname: Brandish
authors.forename: K I
authors.initials: KI
authors.lastname: Kimura
authors.forename: M
authors.initials: M
authors.lastname: Inukai
authors.forename: R
authors.initials: R
authors.lastname: Southgate
authors.forename: J T
authors.initials: JT
authors.lastname: Lonsdale
authors.forename: T D
authors.initials: TD
authors.lastname: Bugg
mesh_terms: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D001667:Binding, Competitive; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology*; D007700:Kinetics; D009705:Nucleosides / Q000494:pharmacology; D017855:Transferases (Other Substituted Phosphate Groups) / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology*
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D009705:Nucleosides; C047544:liposidomycins; D014415:Tunicamycin; C059803:mureidomycin A; D017855:Transferases (Other Substituted Phosphate Groups); C100130:phospho-N-acetylmuramoyl pentapeptide transferase