title: The generation of the rifamycin binding site in the beta subunit of E. coli RNA polymerase through subunit interactions.
abstract: Spectral studies were performed using rifampicin quinone to investigate the generation of the rifamycin binding site in the beta subunit of E. coli RNA polymerase due to subunit interactions. The spectrum of rifampicin quinone is not significantly altered in the presence of the beta subunit. In the case of the alpha 2 beta subassembly, a negative difference spectral band at 330 nm is observed for rifampicin quinone, whereas in the presence of either the holoenzyme or core polymerase a positive band at 348 and a negative one at 318 are observed. In affinity labeling studies using 3-(2-bromo[1-14C]acetamidoethyl)-thiorifamycin, it was demonstrated that the isolated beta subunit is nonspecifically modified by this reagent. However, in the case of both the alpha 2 beta subassembly and core polymerase, the beta subunit is specifically modified.
authors.affiliation: Department of Biochemistry, East Carolina University, School of Medicine, Greenville, NC 27858.
authors.forename: J F
authors.initials: JF
authors.lastname: Lowder
authors.forename: R S
authors.initials: RS
authors.lastname: Johnson
mesh_terms: D001665:Binding Sites; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology; D046911:Macromolecular Substances; D011485:Protein Binding; D012293:Rifampin / Q000378:metabolism; D012294:Rifamycins / Q000378:metabolism*; D013057:Spectrum Analysis
chemical_list: D046911:Macromolecular Substances; D012294:Rifamycins; D012321:DNA-Directed RNA Polymerases; D012293:Rifampin