Professor, Department of Physics & Astronomy
Spin labels are versatile Electron Paramagnetic Resonance (EPR) probes used in the study of the dynamical and structural properties of a wide verity of molecules and their surroundings. My primary goal is to improve data analysis of the EPR spin label spectrum in the fast motional regime by using nonlinear least-squares fitting. Spectral fitting improves the accuracy and sensitivity of EPR parameters, as well as separates the inhomogeneous and homogeneous contributions to the EPR linewidth. In order to employ the full power of fitting the fitting function used in the data analysis of an EPR spectrum has to describe the underlying physics of the problem in its entirety. This way we have been able to study the problems, such as the reencounter rate between spin label molecules in liquids that eluded EPR spectroscopists for a very long time. The second goal is to apply the improved fitting techniques in the study of complex chemical and biological systems such as micelles and vesicles. Due to the spin label sensitivity to the concentration of water in its surroundings, I am especially interested in studying the effect of the hydration state of the vesicle surface on vesicle fusion. My goal is to show that the hydration properties of the vesicle surface in case of cation-induced vesicle fusion, temperature-induced vesicle fusion and peptide-induced vesicle fusion for a given phospholipid are very similar.