Fluorescence polarization studies were used to study the interaction of a fluorescein-labelled conjugate of the Escherichia coli cyclic AMP receptor protein (F-CRP) and RNA polymerase. Under conditions of physiological ionic strength, F-CRP binds to RNA polymerase holoenzyme in a cyclic AMP-dependent manner; the dissociation constant was about 3 microM in the presence of cyclic AMP and about 100 microM in its absence. Binding to core RNA polymerase under the same conditions was weak (Kdiss. approx. 80-100 microM) and independent of cyclic AMP. Competition experiments established that native CRP and F-CRP compete for the same binding site on RNA polymerase holoenzyme and that the native protein binds about 3 times more strongly than does F-CRP. Analytical ultracentrifuge studies showed that CRP binds predominantly to the monomeric rather than the dimeric form of RNA polymerase.
Research Article| March 15 1988
Binding of the cyclic AMP receptor protein of Escherichia coli to RNA polymerase
Biochem J (1988) 250 (3): 897–902.
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M Pinkney, J G Hoggett; Binding of the cyclic AMP receptor protein of Escherichia coli to RNA polymerase. Biochem J 15 March 1988; 250 (3): 897–902. doi: https://doi.org/10.1042/bj2500897
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