title: Fusidic acid targets elongation factor G in several stages of translocation on the bacterial ribosome.
abstract: The antibiotic fusidic acid (FA) targets elongation factor G (EF-G) and inhibits ribosomal peptide elongation and ribosome recycling, but deeper mechanistic aspects of FA action have remained unknown. Using quench flow and stopped flow experiments in a biochemical system for protein synthesis and taking advantage of separate time scales for inhibited (10 s) and uninhibited (100 ms) elongation cycles, a detailed kinetic model of FA action was obtained. FA targets EF-G at an early stage in the translocation process (I), which proceeds unhindered by the presence of the drug to a later stage (II), where the ribosome stalls. Stalling may also occur at a third stage of translocation (III), just before release of EF-G from the post-translocation ribosome. We show that FA is a strong elongation inhibitor (K50% ≈ 1 μm), discuss the identity of the FA targeted states, and place existing cryo-EM and crystal structures in their functional context.
authors.affiliation: From the Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, 751 24 Uppsala, Sweden and 3H Biomedical AB, Dag Hammarskjölds Väg 34A, Uppsala Science Park, 751 83 Uppsala, Sweden.
authors.forename: Anneli
authors.initials: A
authors.lastname: Borg
authors.affiliation: From the Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, 751 24 Uppsala, Sweden and.
authors.forename: Mikael
authors.initials: M
authors.lastname: Holm
authors.affiliation: From the Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, 751 24 Uppsala, Sweden and.
authors.forename: Ikue
authors.initials: I
authors.lastname: Shiroyama
authors.affiliation: From the Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, 751 24 Uppsala, Sweden and.
authors.forename: Vasili
authors.initials: V
authors.lastname: Hauryliuk
authors.affiliation: From the Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, 751 24 Uppsala, Sweden and.
authors.forename: Michael
authors.initials: M
authors.lastname: Pavlov
authors.affiliation: From the Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, 751 24 Uppsala, Sweden and.
authors.forename: Suparna
authors.initials: S
authors.lastname: Sanyal
authors.affiliation: From the Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, 751 24 Uppsala, Sweden and ehrenberg@xray.bmc.uu.se.
authors.forename: Måns
authors.initials: M
authors.lastname: Ehrenberg
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D005672:Fusidic Acid / Q000494:pharmacology*; D010441:Peptide Chain Elongation, Translational / Q000187:drug effects; D020653:Peptide Elongation Factor G / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D012270:Ribosomes / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D020653:Peptide Elongation Factor G; D011500:Protein Synthesis Inhibitors; D005672:Fusidic Acid
keywords: Antibiotic Action; Elongation Factor G; Fusidic Acid; Kinetics; Protein Synthesis; Slow Inhibitors; Translation Elongation Factor; Translocation