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Start of funding 01.01.2010
Optical Tweezers and Fluorescence Microscope Combo
PD Dr. Sören Doose
University of Würzburg
Lehrstuhl für Biotechnologie und Biophysik
Dr. James Tsay
University of California, San Diego
Department of Physics
Dynamic processes in biomolecular systems are studied by fluorescence and single-molecule force spectroscopy. Optical tweezers allow the investigation of force-response dependences with single biomolecules embedded in aqueous solution. We will study molecular recognition and protein-protein interactions using optical tweezers in combination with fluorescence spectroscopy. Homodimer formation of proteins in which each monomer has a single binding site is of great importance for crosslinking and other multivalent signalling interactions. Simultaneous observation of homodimer formation and dissociation together with protein conformational changes and molecular-recognition processes will provide important information about the monomer-homodimer equilibrium and its functional role in cellular biology.
Final report:
Single molecule studies of proteins’ biophysical properties are feasible by force spectroscopy using
optical tweezers or by optical fluorescence spectroscopy. A combination of these techniques
enables new insights from correlating simultaneously acquired signatures of both techniques.
Thanks to BaCaTeC travel funding, a PhD student from the Department of Biotechnology and
Biophysics (University of Würzburg) could be trained by Dr. James Tsay and colleagues in setting
up optical tweezers during an extended visit to the laboratory of Prof. Douglas Smith (UC San
Diego). With the acquired knowledge we have then assembled a microscope that is capable of
simultaneous fluorescence detection and optical trapping of small polystyrene beads in aqueous
solution at the University of Würzburg. The effects of infrared radiation on the fluorescence
properties of various organic dyes were studied setting the stage for application to biophysical
studies of molecular recognition processes.