Twisted or shifted? Fluorescence measurements of late intermediates in transcription initiation by T7 RNA polymerase.
T7 RNA polymerase undergoes dramatic structural rearrangements in the transition from initiation to elongation. Two models have been proposed for promoter-bound intermediates late in the transition. (i) A subset of promoter interactions are maintained through completion of the protein conformational (twist) change, and (ii) concerted movement (shift) of all promoter-binding elements away from the growing DNA-RNA hybrid leads to an open intermediate, with large-scale domain rotations deferred until after promoter release. Fluorescence resonance energy transfer measurements provide very strong support for the latter.
Turingan
Rosemary S
RS
Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Theis
Karsten
K
Martin
Craig T
CT
D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000235:genetics*; D005453:Fluorescence; D031541:Fluorescence Resonance Energy Transfer; D008954:Models, Biological; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics*
D014764:Viral Proteins; C062210:bacteriophage T7 RNA polymerase; D012321:DNA-Directed RNA Polymerases