Positioning of Region 4 of the Escherichia coli RNA Polymerase ς(70) Subunit by a Transcription Activator

A DNA cleavage reagent, specifically tethered to residue 581 of the Escherichia coli RNA polymerase ς(70) subunit, has been used to investigate the location of ς(70) region 4 in different complexes at the galp(1) promoter and the effect of the cyclic AMP receptor protein. The positions of DNA cleavage by the reagent are not affected by the cyclic AMP receptor protein. We conclude that transcription activation at the galp(1) promoter by the cyclic AMP receptor protein does not involve major conformation changes in or repositioning of ς(70) region 4.