title: Rifampicin binding as a probe for subunit interactions in Escherchia coli RNA polymerase.
abstract: The binding of the inhibitor rifampicin to RNA polymerase (alpha2betabeta') and its deficient subunit mixtures was investigated. The ability of beta to bind stoichiometric amounts of rifampicin was restored by formation of the alpha2beta subassembly. beta,beta' alpha, betabeta' and alpha2beta' were unable to bind rifampicin. RNA polymerase denatured with 6 M guanidine hydrochloride and dialysed against a renaturing buffer at 0degrees C ("renatured inactive enzyme") bound stoichiometric amounts of rifampicin but had lost the ability of bind dna. compared with native RNA polymerase "renatured inactive" enzyme possessed a markedly different tertiary structure as judged by limited proteolysis.
mesh_terms: D001665:Binding Sites; D004247:DNA; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D006146:Guanidines; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D011485:Protein Binding; D011489:Protein Denaturation; D012293:Rifampin / Q000378:metabolism*
chemical_list: D006146:Guanidines; D046911:Macromolecular Substances; D010446:Peptide Fragments; D004247:DNA; D012321:DNA-Directed RNA Polymerases; D012293:Rifampin