title: Isolation and characterization of the gene coding for the major sigma factor of Rickettsia prowazekii DNA-dependent RNA polymerase.
abstract: The gene coding for the major sigma factor of Rickettsia prowazekii, an obligate intracellular parasitic bacterium, has been isolated utilizing an oligodeoxyribonucleotide as a probe to a conserved region of major sigma factors. Nucleotide sequence analysis revealed an open reading frame of 1905 bp that could encode a protein of 635 amino acids (aa) with a calculated molecular size of 73 kDa (sigma 73). R. prowazekii sigma 73 displayed extensive homology with major sigma factors from a variety of eubacteria. Comparison of the major sigma factors from Escherichia coli and R. prowazekii revealed 44.9% aa identity. R. prowazekii sigma 73 produced in E. coli minicells migrated as a 85-kDa protein when analyzed by sodium dodecyl sulfate-polyacrylamide-gel electrophoresis. This anomalous migration is characteristic of eubacterial major sigma factors and agrees with the migration noted for the purified rickettsial sigma protein. Despite a similarity to the E. coli sigma 70 encoded by rpoD, R. prowazekii sigma 73 did not complement E. coli rpoD temperature-sensitive mutants.
authors.affiliation: Department of Medicine, University of South Alabama College of Medicine, Mobile 36688.
authors.forename: G L
authors.initials: GL
authors.lastname: Marks
authors.forename: H H
authors.initials: HH
authors.lastname: Winkler
authors.forename: D O
authors.initials: DO
authors.lastname: Wood
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D012321:DNA-Directed RNA Polymerases; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D012283:Rickettsia prowazekii / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012808:Sigma Factor; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases