EPR Studies of Protein-protein Interactions: Distances, Orientation and Molecular Modeling

Florida State University, Tallahassee FL

Investigators

Abstract

Myosin is a mechanochemical enzyme that transforms the chemical energy of ATP into mechanical force. As with any motor, biological or man-made, the force is generated by movement of specific parts. The success of x-ray crystallography and electron microscopy in the past decade revealed the anatomy of the motor parts in various intermediate states of the ATPase cycle. What needs to be done now is to: (a) verify that the crystal structures exist in solution; (b) find missing intermediate states that involve actin as well as myosin; (c) correlate the structures in time i.e. build a movie from static snapshots. This project addresses these questions using electron paramagnetic resonance spectroscopy. It combines recent developments in spectroscopy, computational biology, synthetic chemistry, and molecular biology. These novel approaches include (a) new distance measurement technique, (b) site directed spin labeling, (c) the use of newly designed bifunctional spin labels, and lastly, (d) direct interpretation of EPR signals in structural terms. Broader impacts: This project is expected to have an impact that transcends biological motor systems. Two aspects deal with the development of electron paramagnetic resonance spectroscopy as a structural technique. Such development is timely, as the technique is becoming more popular, yet the theory that targets structural biology aspects is lagging behind similar developments in nuclear magnetic resonance spectroscopy and electron microscopy. The tools and techniques developed in this project could be applied to solve many structural biology problems. The broader impacts also include integration of teaching and research activities as well as training aspects. This project will continue to train post-doctoral fellows, graduate students and undergraduate students at the interface of chemistry, physics, and biology.