title: Identifying interacting regions in the beta subunit of Escherichia coli RNA polymerase.
abstract: Numerous physical and genetic approaches have identified residues in the alpha, beta, beta' and sigma subunits of Escherichia coli RNA polymerase that are involved in transcriptional processes; in contrast, relatively little data exist to demonstrate interacting regions within or between the subunits themselves. As a means of identifying regions in the beta subunit that may interact, we have sought intragenic suppressor mutations of a class of elongation-defective and termination-proficient inviable rpoB alleles that affect highly conserved residues. We obtained intragenic allele-specific suppressors of GD566 (located in conserved region D) and AV676 (located in conserved region E). With one exception, these allele-specific suppressors also map to highly conserved regions of the beta subunit. Allele specific suppression is a genetic criterion for protein-protein interaction. Moreover, the functional properties of the mutants suggests that suppression is likely to result from protein-protein interaction rather than from functional compensation. Our suppression studies provide evidence for the interaction of conserved regions B and D as well as conserved regions E and H of the beta polypeptide. We suggest that these, as well as other conserved regions of the beta polypeptide, may interact with each other to provide a framework for the function of the enzyme.
authors.affiliation: Department of Bacteriology, University of Wisconsin-Madison 53706, USA.
authors.forename: P L
authors.initials: PL
authors.lastname: Tavormina
authors.forename: W S
authors.initials: WS
authors.lastname: Reznikoff
authors.forename: C A
authors.initials: CA
authors.lastname: Gross
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002874:Chromosome Mapping; D017124:Conserved Sequence; D004269:DNA, Bacterial; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D013489:Suppression, Genetic; D014158:Transcription, Genetic
chemical_list: D004269:DNA, Bacterial; D012321:DNA-Directed RNA Polymerases