Regensburg 2007 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 22: Molecular Machines
BP 22.8: Vortrag
Donnerstag, 29. März 2007, 12:00–12:15, H43
Single-molecule fluorescence resonance energy transfer studies of RNA polymerase II — •Jens Michaelis1,2, Joanna Andrecka1, Florian Brückner3, and Patrick Cramer1,3 — 1Ludwig-Maximilians-Universität München, Department Chemie und Biochemie, Butenandstr.11, 81377 München — 2Center for Nanoscience, CeNS — 3Ludwig-Maximilians-Universität München, Gene Center
The crystal structure of the elongation complex of the complete 12 subunit RNA polymerase II (Pol II) reveals incoming template and non-template DNA, a seven base pair DNA/RNA hybrid, and three nucleotides each of separating DNA and RNA. Albeit, longer oligomers were used in preparation, the exit pathway of the nascent RNA could not be observed, presumably due to the inherent flexibility.
To determine the position of the nascent RNA, we have measured the distances between several known points on the Pol II elongation complex and the RNA using single pair fluorescence resonance energy transfer (sp-FRET). For a given position on the RNA we have measured three distances to known positions within the elongation complex, in order to map the unknown RNA position by triangulation. We have determined the position of the end of a 17-nt, 20-nt and 23-nt RNA thus mapping the exit pathway of the RNA product. As the RNA grows longer, we observe binding of to the dock domain and dynamical repositioning of the RNA.