High Pressure Study on Enzyme Mechanism

Abstract

Carbonic anhydrases (CAs) are mostly zinc metalloenzymes that catalyze the reversible hydration/dehydration of CO2/HCO3. Although CAs have been extensively studied to investigate the proton-transfer process that occurs in the active site, their underlying mechanism is still not fully understood. In this presentation, we show crystallographic structures of apo-CA (zinc free, no enzymatic activity) and holo-CA (zinc containing native form from human) pressurized at multiple CO2 (substrate) conditions to explore the catalytic mechanism. The structural comparison provides evidence that the zinc ion in the active site of CA has a long-range role in water organization beyond the ionization of the zinc-bound water.