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BP: Fachverband Biologische Physik
BP 20: DNA, RNA and Chromatin
BP 20.8: Talk
Thursday, March 26, 2009, 16:15–16:30, HÜL 186
Investigation of the three-dimensional structure of chromatin — •René Stehr1, Nick Kepper2, Ramona Ettig2, Karsten Rippe2, and Gero Wedemann1 — 1Fachhochschule Stralsund, System Engineering and Information Management, 18435 Stralsund, Germany — 2Deutsches Krebsforschungszentrum & BioQuant, Research Group Genome Organization & Function, 69120 Heidelberg, Germany
We developed a new coarse-grained computer model of chromatin, which enhances the common two-angle model by additional four angles and uses a new nucleosome-nucleosome interaction potential. Based on recent experimental data of native and reconstituted chromatin, three models of chromatin fibers were systematically analyzed by Monte Carlo simulations [1,2]. The results indicate the strong influence of the nucleosome repeat length on the stability of the fiber formation. A model was proposed, in which changes of the chromatin fiber conformation induced by linker histone H1 binding are reproduced by relatively small changes of the local nucleosome geometry. Furthermore, key factors for the control of compaction and higher order folding of the chromatin fiber were identified. We have further developed this approach and are applying it to the analysis of the conformational space of the chromatin fiber, fiber force spectroscopy experiments and atomic force microscopy imaging of chromatin fibers.
[1] Stehr, R., N. Kepper, K. Rippe, and G. Wedemann. Biophys. J. 95:3677 (2008).
[2] Kepper, N., D. Foethke, R. Stehr, G. Wedemann, and K. Rippe. Biophys. J. 95:3692 (2008).