Photochemical cross-linking studies on the interaction of Escherichia coli RNA polymerase with T7 DNA. [Identification of subunits involved in enzyme-template interaction]

Journal Article · Tue Jul 25 00:00:00 EDT 1978 · Biochemistry; (United States)

OSTI ID:6687970

Hillel, Z; Wu, C W

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), Vol. 17:15
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
59 BASIC BIOLOGICAL SCIENCES
CROSS-LINKING
PHOTOCHEMICAL REACTIONS
DNA
POLYMERASES
BACTERIOPHAGES
BIOLOGICAL RADIATION EFFECTS
ESCHERICHIA COLI
IN VITRO
IRRADIATION
RADIOINDUCTION
RNA
SOLUTIONS
ULTRAVIOLET RADIATION
BACTERIA
BIOLOGICAL EFFECTS
CHEMICAL REACTIONS
DISPERSIONS
ELECTROMAGNETIC RADIATION
ENZYMES
MICROORGANISMS
MIXTURES
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PARASITES
POLYMERIZATION
RADIATION EFFECTS
RADIATIONS
VIRUSES
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