Isolation and characterization of the gene coding for the major sigma factor of Rickettsia prowazekii DNA-dependent RNA polymerase.
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.
Marks
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Department of Medicine, University of South Alabama College of Medicine, Mobile 36688.
Winkler
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Wood
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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*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012808:Sigma Factor; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases