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dc.contributor.advisorWatson, Benjamin F.
dc.creatorLim, Daniel Van
dc.description.abstractThe bacterial enzyme DNA-dependent RNA polymerase, which is responsible for synthesis of all types of cellular RNA, is composed of several discrete protein subunits. Although the structure of the enzyme and its constituent polypeptide chains have been extensively studied, little work has been done on the relationship of these individual subunits to the overall role of the enzyme in the transcription process. Transcription is known to consist of several discrete steps which involve binding of polymerase to DNA, RNA chain initiation, elongation, and termination. In this study, drug-resistant mutants and temperature-sensitive mutants of RNA polymerase were independently isolated from Escherichia coli. Both types of mutants were studied in vivo with regard to growth parameters and macromolecular synthesis. In addition, RNA polymerase was purified from each of the mutants as well as from their parental strains. Studies involving in vitro assays of these purified enzymes indicate that the drug-resistant mutants contained RNA polymerase which was resistant to the effects of the antibiotic rifampicin. In addition, amino acid analyses suggest the possibility of a slight amino acid difference in the rifampicin-resistant enzyme as compared to the parental enzyme. The two temperature-sensitive enzymes purified in this study were found to have fewer purine-directed initiations as well as less chain elongation at the nonpermissive temperature as compared to the permissive temperature. It was further found that electrophoretic analyses of these temperature-sensitive enzymes revealed an altered ?â subunit. Together with ion-exchange chromatography and amino acid analyses of these altered enzymes and the parental enzyme, this would seem to suggest that the mutants contain a RNA polymerase temperature-sensitive in purine-directed initiations and altered in the ?â subunit.en
dc.format.extent152 leavesen
dc.rightsThis thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use.en
dc.subject.classification1973 Dissertation L732
dc.titleAn investigation of subunit structure and function of DNA-dependent RNA polymerase from selected drug-resistant strains and temperature-sensitive strains of Escherichia colien
dc.typeThesisen A&M Universityen of Philosophyen
dc.contributor.committeeMemberFoster, B. G.
dc.contributor.committeeMemberKrise, George M.
dc.contributor.committeeMemberMagill, C. W.
dc.contributor.committeeMemberNagyvary, Joseph
dc.format.digitalOriginreformatted digitalen
dc.publisher.digitalTexas A&M University. Libraries

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