Peer-Reviewed Journal Details
Mandatory Fields
Wang, Y.P., Kolb, A., Buck, M., Wen, J., O'Gara, F.,and Buc, H.;
1998
February
The Embo Journal
CRP interacts with promoter-bound sigma(54) RNA polymerase and blocks transcriptional activation of the dctA promoter.
Published
()
Optional Fields
cAMP-CRP repression E sigma(54) holoenzyme-regulated promoters loop formation protein-protein interactions regulation in E-coli ENHANCER-BINDING PROTEIN NITROGEN-FIXATION GENES CAMP RECEPTOR PROTEIN ESCHERICHIA-COLI RHIZOBIUM-MELILOTI PHOSPHOTRANSFERASE SYSTEM KLEBSIELLA-PNEUMONIAE ALPHA-SUBUNIT CYCLIC-AMP CENTRAL DOMAIN
17
3
786
796
The cAMP receptor protein (CRP) is an activator of sigma(70)-dependent transcription, Analysis of the sigma(54)-dependent dctA promoter reveals a novel negative regulatory function for CRP, CRP can bind to two distant sites of the dctA promoter, sites which overlap the upstream activator sequences for the DctD activator, CRP interacts with E sigma(54) bound at the dctA promoter via DNA loop formation, When the CRP-binding sites are deleted, CRP still interacts in a cAMP-dependent manner with the stable E sigma(54) closed complex via protein-protein contacts, CRP is able to repress activation of the dctA promoter, even in the absence of specific CRP-binding sites, CRP affects both the final level and the kinetics of activation, The establishment of the repression and its release by the NtrC activator proceed via slow processes, The kinetics suggest that CRP favours a new form of closed complex which interconverts slowly with the classical closed intermediate, Only the latter is capable of interacting with an activator to form an open promoter complex, Thus, E sigma(54) promoters are responsive to CRP, a protein unrelated to sigma(54) activators, and the repression exerted is the direct result of an interaction between E sigma(54) and the CRP-cAMP complex.
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