Biocatalysis and Protein Engineering
Enzymes are protein catalysts that have evolved over millennia to perform the exquisite chemical transformations that underpin all of cellular life. Our group is dedicated to developing synthetically useful chemical transformations using enzyme catalysts. Often, naturally occurring enzymes are slow or inefficient catalysts when asked to perform new transformations and our group uses an engineering algorithm called directed evolution to make new enzymes with improved function. To build and understand new biocatalytic transformations, researchers in the group have the opportunity to learn a unique combination of fundamental principles and skills from physical organic chemistry, molecular biology, and protein biophysics.
A common feature of enzymes is the use of a cofactor, either an organic molecule or metal, to facilitate complex transformations. We believe that the reactivity of natural cofactors may be altered to unveil new, desirable chemical reactions, but little is known about how to effectively tune cofactor chemistry. We are elucidating the structural determinates of pyridoxal phospate (PLP, vitamin B6) reactivity by studying the lineages of enzymes evolved to do new reactions, which are produced from our engineering efforts (see above). Techniques include X-ray crystallography, UV-vis spectroscopy, and enzyme kinetics.
Understanding how enzymes work requires a combination of skills and techniques. We use UV-vis spectroscopy to probe enzymes that use colored cofactors, which can reveal which steps in a catalytic cycle are fast and where new reactions stall. This information is augmented with X-ray crystallography, which can reveal atomic-level details of how mutations impact active site structure and promote new transformations.