The University Scholars Program

Human carbonic anhydrase II (HCAII) has been extensively used in industrial applications to lower the atmospheric emissions of carbon dioxide (CO2) produced during the burning of fossil fuels. However, the current industrial protocol for limiting atmospheric CO2 emission utilizes high temperatures (>70℃) and results in an acidic (pH < 5.0) environment, conditions in which HCAII cannot efficiently function. Therefore, my proposed project will involve the design of more stable variants of HCAII that can withstand the extreme environment in industrial settings. HCA II is a zinc-containing metalloenzyme that catalyzes the hydration of CO2 to yield bicarbonate and a proton at a turnover rate of 106 s-1, making it one of the fastest known enzymes. By rationally engineering disulfide bridges, elements known to help stabilize proteins and absent in HCAII, I aim to create a more stable variant that will be more thermally and pH stable than wild-type HCA II. It is also essential, however, for these mutations not to interfere with the catalytic efficiency that HCA II possesses. I will be using a wide array of biophysical techniques including X-ray crystallography, differential scanning calorimetry and isotope-labeled mass spectrometry to elicit the structure, stability and kinetic activity of the engineered HCAII variants, respectively. If any of these mutants prove to be more thermo- and acido-stabile than the wild-type HCAII while also retaining its characteristic high catalytic efficiency, it could provide a basis for a cheap, renewable source for atmospheric CO2 sequestration in the industrial setting.