sigma E changed to sigma B specificity by amino acid substitutions in its -10 binding region.
The association of a sigma factor (sigma) with RNA polymerase in bacteria determines its specificity of promoter utilization. To identify amino acid residues in sigma E from Bacillus subtilis that determine the specificity of its interaction with the nucleotides at the -10 region of its cognate promoters, we tested whether base pair substitutions in the -10 region of a sigma B-dependent promoter could signal its utilization by sigma E-RNA polymerase. We found that a combination of base pair substitutions at positions -15 and -14 of the sigma B-dependent ctc promoter resulted in its utilization by sigma E-RNA polymerase in vivo. We also found that the combination of two amino acid substitutions at positions 119 and 120 in sigma E changed its specificity for promoter utilization, resulting in a sigma factor that directed transcription from the sigma B-dependent ctc promoter, but not from sigma E-dependent promoters. These results suggest that amino acid residues at positions 119 and 120 determine, at least in part, the specificity of interactions between sigma E and the nucleotides in the -10 region of its cognate promoters.
Tatti
K M
KM
Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
Moran
C P
CP
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000502:physiology; D001426:Bacterial Proteins / Q000502:physiology*; D001483:Base Sequence; D012321:DNA-Directed RNA Polymerases / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012808:Sigma Factor / Q000737:chemistry / Q000502:physiology*; D014157:Transcription Factors / Q000737:chemistry / Q000502:physiology*; D014158:Transcription, Genetic / Q000235:genetics*
D000596:Amino Acids; D001426:Bacterial Proteins; D011993:Recombinant Fusion Proteins; C079011:SigB protein, Bacteria; D012808:Sigma Factor; D014157:Transcription Factors; C063202:sporulation-specific sigma factors; D012321:DNA-Directed RNA Polymerases