William R. McClure

Learn More
The DNA sequence of 168 promoter regions (-50 to +10) for Escherichia coli RNA polymerase were compiled. The complete listing was divided into two groups depending upon whether or not the promoter had been defined by genetic (promoter mutations) or biochemical (5' end determination) criteria. A consensus promoter sequence based on homologies among 112(More)
Promoter-specific lags in the approach to the steady-state rate of abortive initiation were observed when Escherichia coli RNA polymerase was added to initiate the reaction. The lag times were related to the time required for free enzyme and free promoter to combine and isomerize into a functionally active complex. The lag times measured for several(More)
The forward and reverse kinetics of open complex formation between Escherichia coli RNA polymerase and the lac UV5 promoter have been studied in the temperature range of 15-42 degrees C. The standard two-step model, involving the formation of a closed intermediate, RPc, followed by an isomerization that leads to the active complex RPo, could not account for(More)
An analysis of the sequence information contained in a compilation of published binding sites for E. coli integration host factor (IHF) was performed. The sequences of twenty-seven IHF sites were aligned; the base occurrences at each position, the information content, and an extended consensus sequence were obtained for the IHF site. The base occurrences at(More)
CRP-cAMP was shown to activate transcription initiation at the Escherichia coli lac promoter in vitro as a result of two separate effects. An indirect component of the activation resulted from an enhancement of the fraction of promoters productively bound by RNA polymerase. This effect was due largely to CRP-cAMP repression of RNA polymerase binding to an(More)
We show that dam- mutants are a major class of E. coli mutants with increased IS10 activity. IS10 has two dam methylation sites, one within the transposase promoter and one within the inner terminus where transposase presumably binds. Absence of methylation results in increased activity of both promoter and terminus, and completely accounts for increased(More)
The first steps of transcription initiation include binding of RNA polymerase to a promoter to form an inactive, unstable, closed complex (described by an equilibrium constant, K(B)) and isomerization of the closed complex to an active, stable, open complex (described by a forward rate constant, k(f)). lambda cI protein activates the PRM promoter by(More)
The mechanism of rifampicin inhibition of Escherichia coli RNA polymerase was studied with a newly developed steady state assay for RNA chain initiation and by analysis of the products formed with several 5'-terminal nucleotides. The major effect of rifampicin was found to be a total block of the translocation step that would ordinarily follow formation of(More)