Sequence-specific interactions between promoter DNA and the RNA polymerase sigma factor E.
In order to determine which amino acyl residues in a secondary sigma factor govern its specificity of recognition at the -35 region of promoters, we examined the effects of amino acid substitutions in sigma E in Bacillus subtilis that made the sequence of its putative -35 recognition region more similar to another sigma factor in B. subtilis, sigma K. We found that a single amino acid substitution at position 217 of sigma E resulted in a sigma factor that could direct transcription from sigma K-dependent promoters. Furthermore, we tested whether this amino acid substitution in sigma E had changed the specificity of interactions of the sigma with -35 region sequences by examining the activity of the mutant sigma E on derivatives of sigma E-dependent promoters that contained single base-pair substitutions. We found that this substitution in sigma E specifically suppressed the effect of a single base-pair substitution at position -31 in a sigma E-dependent promoter spoIIID. The amino acyl residue at another position (219) on sigma E affected the specificity of interaction with position -33 in spoIIID promoter. The amino acyl residues at the two positions in sigma E, 217 and 219, that determine the specificity of interactions between the sigma and base-pairs in the -35 region of its cognate promoters (positions -33 and -31, respectively, in the spoIIID promoter) probably closely contact these base-pairs.
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D005785:Gene Conversion; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D013171:Spores, Bacterial / Q000235:genetics; D013489:Suppression, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D012808:Sigma Factor; C071977:SpoIIID protein, Bacillus; D014157:Transcription Factors; C084190:sigma K; C063202:sporulation-specific sigma factors; D012321:DNA-Directed RNA Polymerases