title: A single amino acid substitution in sigma E affects its ability to bind core RNA polymerase.
abstract: We have examined the role of the most highly conserved region of bacterial RNA polymerase sigma factors by analyzing the effect of amino acid substitutions and small deletions in sigma E from Bacillus subtilis. sigma E is required for the production of endospores in B. subtilis but not for vegetative growth. Strains expressing each of several mutant forms of sigE were found to be deficient in their ability to form endospores. Single amino acid substitutions at positions 68 and 94 resulted in sigma factors that bind with less affinity to the core subunits of RNA polymerase. The substitution at position 68 did not affect the stability of the protein in B. subtilis; therefore, this substitution probably did not have large effects on the overall structure of the sigma factor. The substitution at position 68 probably defines a position in sigma E that closely contacts a subunit of RNA polymerase, while the substitution at position 94 may define a position that is important for protein stability or for binding to core RNA polymerase.
authors.affiliation: Department of Microbiology and Immunology, Emory University, Atlanta, Georgia 30322, USA.
authors.forename: M F
authors.initials: MF
authors.lastname: Shuler
authors.forename: K M
authors.initials: KM
authors.lastname: Tatti
authors.forename: K H
authors.initials: KH
authors.lastname: Wade
authors.forename: C P
authors.initials: CP
authors.lastname: Moran
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D017124:Conserved Sequence; D004252:DNA Mutational Analysis; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D012808:Sigma Factor; D013045:Species Specificity; D013171:Spores, Bacterial / Q000254:growth & development; D013329:Structure-Activity Relationship; D014157:Transcription Factors
chemical_list: D001426:Bacterial Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C063202:sporulation-specific sigma factors; D012321:DNA-Directed RNA Polymerases