Evaluation of transient protein states

Despite recent advances in biophysical techniques and computational approaches for the investigation of biomolecular systems, the characterization of the dynamic equilibria of protein states remains a demanding challenge due to the elusive nature of the dynamic processes that regulate these equilibria. In particular, the sparsely populated, transient states are difficult to characterize at the atomic level because they are ""invisible"" to the biophysical methods that detect protein states with the lowest energy or the highest abundance. There is growing evidence for the importance of transient, thermally accessible protein states in the biological function of proteins. The main goal of the proposed project is to develop a combined experimental and theoretical approach for the physicochemical characterization at the atomic level of transient protein states close to physiological conditions in aqueous environments. The characterization will allow to relate them to the specific dynamic event that is important for their function. To overcome the problems of averaging and signal assignment, a combination of solution NMR and vibrational spectroscopy operating on different time scales will be used. Together, these spectroscopies can provide access to transient molecular states in dynamic exchange on time scales from picoseconds to milliseconds. To obtain a model-based understanding of the correlation between each type of motion and its effect on dynamic equilibria of states, we will use atomistic molecular dynamic simulations. Algorithms for numerical analysis of the correlation between experimental and computational results will be developed to understand the influence of the individual contributions of the coupled motions on the distribution of protein states. Proteins of different families will be studied, covering a wide range of dynamic events that can cause transitions between thermally accessible protein states. The functional role of the selected proteins in biological processes cannot be comprehensively understood without examining the dynamic equilibria between their possible states without and/or with their binding partners. The expected results may provide presently unforeseen insights into the function of these proteins in health and disease. The developed approach will be widely applicable to the characterization of transient protein states at the atomic level in aqueous environments. The results of the proposed studies can contribute significantly to the understanding of protein function in health and disease and will be of great interest to many specific research areas, such as molecular recognition, molecular signal transduction, enzyme catalysis, protein folding and binding, and target-based design and drug discovery.