This project aims to understand the physical and chemical principles that govern the function of a large class of biologically important proteins, called "tandem repeat proteins". In particular, the research focuses on understanding the relationship between tandem repeat protein structure in a protein found in muscle fibers and their ability to transduce force. The research involves a powerful combination of experimental and computational techniques, carried out by scientists at two University of Minnesota campuses. Its success will have impact on the understanding of force transduction in biological systems and establish a new approach to solving previously intractable problems in the biological sciences. It will provide valuable training for both undergraduate and graduate students, who will carry out most of the research. More broadly, this research will enhance educational programs at both campuses, and it will enrich an established regional educational program in this field, in collaboration with the Biophysical Society.
This research focuses on proteins containing tandem repeats that include intrinsically disordered regions. Dystrophin serves as the model protein for this study. The central hypothesis is that disorder plays a critical role in the energetics and mechanics of these proteins. Therefore, the project combines experimental and computational tools that are optimal for probing disorder-to-order transitions in proteins. The first aim combines several high-resolution calorimetric techniques with computational molecular dynamics simulations to test the hypothesis that energy dissipation in this system involves entropic springs. The second aim employs electron paramagnetic resonance (EPR), fluorescence, and nuclear magnetic resonance (NMR) techniques that are designed to quantify dynamic disorder in proteins. This aim tests the hypothesis that increasing the number of tandem repeats increases protein dynamics and decreases stability. The third aim probes the role of water dynamics in these processes, using Overhauser dynamic nuclear polarization, which combines the principles of NMR and EPR. The overall goal is to advance understanding of the coupling between energetics, structural dynamics, and mechanics in these systems. While this project focuses on dystrophin, the principles and techniques established here will impact the entire field of tandem-repeat proteins, which are involved in numerous neuromuscular functions.
