Photochemical cross-linking studies on the interaction of Escherichia coli RNA polymerase with T7 DNA. [Identification of subunits involved in enzyme-template interaction]
We have identified the subunits of Escherichia coli RNA polymerase which are in close contact with the T7 phage DNA template using photochemical cross-linking. In nonspecific T7 DNA-enzyme complexes which occur in all regions of the DNA, subunits sigma, ..beta.., and ..beta..' were cross-linked to the DNA. In contrast, in specific binary complexes which presumably occur at promotor sites, and in the initiation complex (holoenzyme + T7 DNA + initiator dinucleotides + three nucleoside triphosphates), only sigma and ..beta.. were cross-linked to DNA, while cross-linking of ..beta..' could not be demonstrated. These results (1) do not support the idea that ..cap alpha.. subunits are involved in the enzyme-template interaction, (2) raise the possibility that sigma subunit participates directly in promoter recognition even though isolated sigma does not bind to DNA, and (3) indicate different modes of interaction between RNA polymerase and DNA in nonspecific and specific complexes. These findings are relevant to the mechanism by which RNA polymerase carries out selective transcription.
- Research Organization:
- Albert Einstein Coll., Bronx, NY
- OSTI ID:
- 6687970
- Journal Information:
- Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 17:15; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Cloning and expression of the gene for bacteriophage T7 RNA polymerase
Cloning and expression of the gene for bacteriophage T7 RNA polymerase
Related Subjects
550701 -- Microbiology-- Tracer Techniques
560111* -- Radiation Effects on Biochemicals-- In Vitro-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIA
BACTERIOPHAGES
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CROSS-LINKING
DISPERSIONS
DNA
ELECTROMAGNETIC RADIATION
ENZYMES
ESCHERICHIA COLI
IN VITRO
IRRADIATION
MICROORGANISMS
MIXTURES
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PARASITES
PHOTOCHEMICAL REACTIONS
POLYMERASES
POLYMERIZATION
RADIATION EFFECTS
RADIATIONS
RADIOINDUCTION
RNA
SOLUTIONS
ULTRAVIOLET RADIATION
VIRUSES