The bicyclomycin sensitivities of 38 bicyclomycin-resistant mutants of transcription termination protein rho and the location of their mutations support a structural model of rho based on the F(1) ATPase.
A total of 38 bicyclomycin-resistant mutants of Escherichia coli transcription termination protein Rho have been isolated. The locations of their mutations identify the ATP-binding region as the functional domain inhibited by bicyclomycin. Strains containing the S266C, S266A and L208R Rho mutations are very resistant to bicyclomycin in vivo. In a similar way, the mutant Rho proteins containing these mutations are very resistant to bicyclomycin in vitro. These data suggest that Ser266 and Leu208 might make direct contact with the antibiotic. These two residues are close to each other in the tertiary structure of a model of Rho based on the alpha and beta subunits of the F(1) ATPase, supporting the validity of the model. The strain containing the G337S Rho mutation also has high bicyclomycin resistance, and the proximity of L208, S266 and G337 in the quaternary structure of the Rho model has enabled a candidate bicyclomycin-binding pocket to be delineated. As a whole, the bicyclomycin sensitivities of the mutants are consistent with the locations of their respective mutations in the model of Rho based on the F(1) ATPase, therefore supporting the emerging consensus model of Rho structure.
Moyse
K A
KA
Department of Biology, Indiana University, Bloomington, IN 47405, USA.
Knight
J S
JS
Richardson
J P
JP
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000187:drug effects / Q000235:genetics; D001665:Binding Sites; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000378:metabolism / Q000494:pharmacology*; D004252:DNA Mutational Analysis; D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D006868:Hydrolysis / Q000187:drug effects; D019811:Hydroxylamine / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000187:drug effects / Q000235:genetics; D009153:Mutagens / Q000494:pharmacology; D009154:Mutation / Q000187:drug effects / Q000235:genetics*; D010641:Phenotype; D011485:Protein Binding; D011487:Protein Conformation; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism; D012234:Rho Factor / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism
D019086:Bridged Bicyclo Compounds, Heterocyclic; D009153:Mutagens; D012234:Rho Factor; D019811:Hydroxylamine; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases; C024504:bicozamycin