A surface of Escherichia coli sigma 70 required for promoter function and antitermination by phage lambda Q protein.
The sigma initiation factor sigma70 of Escherichia coli acts not only in promoter recognition and DNA strand opening, but also to mediate the transformation of RNA polymerase (RNAP) to an antiterminating form by the phage lambda gene Q protein. Q is able to bind and modify RNAP when alpha70, still present in the initially elongating enzyme, recognizes a repeat of the -10 promoter element and induces a transcription pause. We have isolated mutations in the rpoD gene for sigma70 that impair Q function because they reduce the ability of sigma70 to recognize the downstream pause site. These mutations identify a locus of sigma70 that is important for the formation and stability of open promoter complex, likely because it mediates protein interactions with RNAP core.
Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York 14853 USA.
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D019943:Amino Acid Substitution / Q000235:genetics; D001216:Asparagine / Q000235:genetics; D001224:Aspartic Acid / Q000235:genetics; D010582:Bacteriophage lambda / Q000235:genetics* / Q000254:growth & development; D001483:Base Sequence; D012321:DNA-Directed RNA Polymerases / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D007930:Leucine / Q000235:genetics; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010443:Peptide Chain Termination, Translational / Q000235:genetics*; D010649:Phenylalanine / Q000235:genetics; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000235:genetics; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000378:metabolism*
D046911:Macromolecular Substances; C066119:Q protein, Bacteriophage lambda; D012808:Sigma Factor; D014764:Viral Proteins; D001224:Aspartic Acid; D010649:Phenylalanine; D001216:Asparagine; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; D007930:Leucine