TY  - THES
AB  - 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. Using single molecule experiments, this work demonstrates that the protein ExpG binds to three different DNA target sequences in a sequence specific manner, albeit with distinct differences in the energy landscape. Dynamic force spectroscopy based on the atomic force microscope (AFM) proves to be sensitive even to small variations of the binding motif. Experiments with DNA mutants lead to a deeper understanding of the binding mechanism.
The method is then applied to a more complex interaction from the same regulatory system. The binding of the quorum sensing receptor ExpR to its DNA target sequence is stimulated by an acyl-homoserine lactone (AHL) effector molecule. Dynamic force spectroscopy yields detailed information about the AHL spectrum, revealing differences in the energy landscape of the protein-DNA interaction depending on the stimulating effector.
DA  - 2005
KW  - DNS-Bindungsproteine , Zwischenmolekulare Kraft , Kraftmikroskopie , Rasterkraftmikroskopie , Ligand-Rezeptor-Wechselwirkung , Genregulation , Effektor , Sinorhizobium meliloti , Atomic force microscopy , Ligand-receptor kinetics , Gene regulation , Quorum sensing , Sinorhizobium meliloti
LA  - ger
PY  - 2005
TI  - Kraftspektroskopische Bindungsstudien an einzelnen Protein-DNA-Komplexen
UR  - https://nbn-resolving.org/urn:nbn:de:hbz:361-7514
Y2  - 2024-11-22T04:48:21
ER  -