The a/b barrel (TIM) enzyme fold is the largest family of protein folds (representing at least 10% of all known protein structures) and has the widest range of enzyme functions. My research focuses on elucidating the structural basis for folding specificity and thermodynamic stability in this class of enzymes and the future application of those principles in protein design. My past work using directed evolution techniques and crystallographic analysis has led to the proposal of specific determinants of protein stability in this class of enzymes. In my current research, I use random PCR mutagenesis to create a library of genetic variants for low or high temperature adapted beta-galactosidases and study the effect of such mutations on protein structure. Using ab initio Monte Carlo simulations, estimations of steric exclusion and the contribution of steric exclusion to main chain and side chain entropy can be made leading to the identification of general classes of substitutions and new models of protein thermostabilization through entropy.
