Architectural requirements for optimal activation by tandem CRP molecules at a class ICRP-dependent promoter

The Escherichia coli cyclic AMP receptor protein (CRP) activates transcription at target promoters by interacting with the C-terminal domain of the RNA polymerase a subunit. We have constructed a set of promoters carrying tandem DNA sites for CRP with one site centred at position -61.5 and the other site located at different upstream positions. Optimal CRP-dependent activation of transcription is observed when the upstream DNA site for CRP is located at position -93.5 or at position -103.5. Evidence is presented to suggest that activation by the upstream-bound CRP molecule is due to interaction with the C-terminal domain of the RNA polymerase (X subunit. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.