Rice University

Proteins are active, flexible molecules that inhabit an ensemble of states to perform functions in vivo. Structural biology, seeking to study proteins in the greatest detail, has used static methods to achieve high-resolution structures. These static structures have greatly furthered our understanding of how proteins behave and do catalysis. Often, however, protein in higher energy states, such as reaction intermediates, cannot be studied using these methods. We want to study the dynamic processes of proteins, specifically photo-conversion of photoreceptors from the dark state to light state and vice-versa. In order to do this, we will use molecular dynamics simulations, x-ray small angle scattering, time-resolved spectroscopy, and time-resolved x-ray crystallography. Our target is TePixJ, a blue/green photoreceptor from photosynthetic bacteria. It houses a bilin chromophore, and static structures of both the blue and green light absorbing forms have been solved. Thus it has a great trigger, light, and understanding both end points will help us in each step of our work. We are currently studying the protein using molecular dynamics simulations, time-resolved spectroscopy, and x-ray small angle scattering.