Solution studies on the structure of bent DNA in the cAMP receptor protein-lac DNA complex

Cyclic AMP receptor protein is involved in the regulation of more than 20 genes. A step in the mechanism of activation of transcription is to induce a significant bending of the DNA upon complex formation between specific DNA and the protein. The induced DNA bending and a structure of the protein-DNA complex were studied by fluorescence energy transfer in 50mM Tris, 1 mM EDTA, and 50mM KCl at pH 7.8 and 20°C. The symmetry of the DNA bend was estimated by measuring the efficiency of transfer between the protein and a label on either the upstream or the downstream end of a lac DNA fragment