Polypeptides containing highly conserved regions of transcription initiation factor sigma 70 exhibit specificity of binding to promoter DNA.
The sigma 70 subunit of E. coli RNA polymerase is required for sequence-specific recognition of promoter DNA. Genetic studies and sequence analysis have indicated that sigma 70 contains two specific DNA-binding domains that recognize the two conserved portions of the prokaryotic promoter. However, intact sigma 70 does not bind to DNA. Using C-terminal and internal polypeptides of sigma 70, carrying one or both putative DNA-binding domains, we demonstrate that sigma 70 does contain two DNA-binding domains, but that N-terminal sequences inhibit the ability of intact sigma 70 to bind to DNA. Thus, we propose that sigma 70 is a sequence-specific DNA-binding protein that normally functions through an allosteric interaction with the core subunits of RNA polymerase.
Dombroski
A J
AJ
Department of Bacteriology, University of Wisconsin, Madison 53706.
Walter
W A
WA
Record
M T
MT
Siegele
D A
DA
Gross
C A
CA
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D004269:DNA, Bacterial / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D010455:Peptides; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor; D005982:Glutathione Transferase; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; D005978:Glutathione