Nitriles are used extensively in the production of specialty chemicals like the polyamide nylon. Nitrile hydratases (NHases) catalyze the hydration of nitriles to amides at ambient temperatures in neutral water. The currently employed industrial conditions for the hydration of nitriles to amides use either strong acids or bases, and are often incompatible with the sensitive structures of the compounds to be produced. NHases have therefore attracted substantial interest as biocatalysts in preparative organic chemistry. Despite the industrial importance of NHase enzymes, the details of how they work remain poorly understood. The objective of this research proposal is to fill this knowledge gap. The interdisciplinary nature of the effort will serve as a platform to increase the participation of women and classically underrepresented graduate and undergraduate students in scientific careers in biophysics, chemistry, and biochemistry. As part of the proposed project, both PI's will participate in the SMART program that mentors Milwaukee area public high school students in research projects.
With this award, the Chemistry of Life Processes Program in the Chemistry Division is funding Drs. Richard C. Holz and Brian Bennett from Marquette University to elucidate the catalytic mechanism of NHase enzymes. An interdisciplinary approach will be used that will incorporate kinetics, spectroscopy, biochemistry, computational chemistry, and both X-ray and neutron crystallography. The proposed experimental approach is designed to address three key questions: i) What is the transition-state structure of nitrile hydration? ii) What are the protonation states of catalytically important species throughout the reaction? and iii) What controls metallocenter assembly in a purported eukaryotic NHase? The successful completion of this research will greatly benefit society by facilitating the intelligent design and manufacture of nitrile-based chiral pharmaceuticals and industrially important specialty chemicals, with enhanced synthetic flexibility and lower environmental impact, than at present.
