Berlin 2005 – wissenschaftliches Programm
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AKB: Biologische Physik
AKB 45: Single Molecule Biophysics
AKB 45.4: Vortrag
Montag, 7. März 2005, 15:30–15:45, TU H2013
Molecular Details of Specific Protein-DNA Interaction — •Frank Wilco Bartels1, Birgit Baumgarth2, Christelle Bahlawane2, Christoph Metzendorf2, Anke Becker2, Dario Anselmetti1, and Robert Ros1 — 1Experimental Biophysics, Faculty of Physics, Bielefeld University — 2Genetics, Faculty of Biology, Bielefeld University
Specific protein-DNA interaction is fundamental for all aspects of gene expression. A regulatory model system is the biosynthesis of exopolysaccharides (EPS) in the nitrogen-fixating bacterium Sinorhizobium meliloti 2011. These sugar polymers promote the bacterium’s symbiosis with alfalfa plants, a process of agricultural importance.
The EPS biosynthesis is controlled by a complex interplay of several proteins, most prominently the transcriptional activator ExpG. In a combination of standard biochemical and single molecule experiments, we demonstrated that the protein ExpG binds to three different DNA target sequences in a sequence specific manner, albeit with distinct differences in the energy landscape.[1] Dynamic force spectroscopy based on the atomic force microscope (AFM) proved to be sensitive even to small variations of the binding motif. Experiments with DNA mutants lead to a deeper understanding of the binding mechanism.[2]
The method is now applied to other proteins from the same regulatory system.
[1] F.W. Bartels et al., J Struct Biol 143 (2003) 145-152
[2] B. Baumgarth et al., Microbiol (2004), in press