Conformational Heterogeneity in RNA Polymerase Observed by Single-Pair FRET Microscopy
Kinetic, structural, and single-molecule transcription measurements suggest that RNA polymerase can adopt many different conformations during elongation. We have measured the geometry of the DNA and RNA in ternary elongation complexes using single-pair fluorescence resonance energy transfer. Six dif...
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Published in | Biophysical journal Vol. 90; no. 12; pp. 4605 - 4617 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Elsevier Inc
15.06.2006
Biophysical Society |
Subjects | |
Online Access | Get full text |
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Summary: | Kinetic, structural, and single-molecule transcription measurements suggest that RNA polymerase can adopt many different conformations during elongation. We have measured the geometry of the DNA and RNA in ternary elongation complexes using single-pair fluorescence resonance energy transfer. Six different synthetic transcription elongation complexes were constructed from DNA containing an artificial transcription bubble, an RNA primer, and core RNA polymerase from
Escherichia coli. Two different RNA primers were used, an 8-mer and a 5′-extended 11-mer. Fluorescent dye labels were attached at one of three positions on the DNA and at the RNA primer 5′-end. Structurally, the upstream DNA runs perpendicular to the proposed RNA exit channel. Upon nucleoside-triphosphate addition, DNA/RNA hybrid separation occurs readily in the 11-mer complexes but not in the 8-mer complexes. Clear evidence was obtained that RNA polymerase exists in multiple conformations among which it fluctuates. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Oana Coban's present address is Steacie Institute for Molecular Sciences, National Research Council Canada, Ottawa, ON K1A 0R6, Canada. Address reprint requests to Prof. Dr. G. Ulrich Nienhaus, Tel.: 49-731-502-3050; E-mail: uli@uiuc.edu; or Don C. Lamb, Tel.: 49-89-2180-77564; E-mail: don.lamb@cup.uni-muenchen.de. Don C. Lamb's present address is Physical Chemistry, Dept. of Chemistry and Biochemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 11 Haus E, 81377 Munich, Germany. |
ISSN: | 0006-3495 1542-0086 |
DOI: | 10.1529/biophysj.105.078840 |