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Opening and Closing of the Bacterial RNA Polymerase Clamp
- Chakraborty, Anirban, Wang, Dongye, Ebright, Yon W., Korlann, You, Kortkhonjia, Ekaterine, Kim, Taiho, Chowdhury, Saikat, Wigneshweraraj, Sivaramesh, Irschik, Herbert, Jansen, Rolf, Nixon, B. Tracy, Knight, Jennifer, Weiss, Shimon, Ebright, Richard H.
- Science 2012 v.337 no.6094 pp. 591-595
- DNA, DNA-directed RNA polymerase, binding sites, crystal structure, energy transfer, fluorescence, models
- Clamping Down Crystal structures of RNA polymerase show that a “clamp” region which surrounds the DNA binding site can adopt conformations ranging from a closed to an open state. Chakraborty et al. (p. 591) used single-molecule fluorescence energy transfer experiments to detect the clamp's conformational changes in solution during the transcription cycle. The results support a model in which a clamp opening allows DNA to be loaded into the active-center cleft and unwound. Direct interactions with DNA likely trigger clamp closure upon formation of a catalytically competent transcription initiation complex.