Structure insights into the catalytic mechanism of carbonic anhydrase

Abstract

Enzymes are molecular machines that accelerate chemical reactions by lowering their activation energy. To understand the enzymatic mechanism at the molecular level, it is essential to observe the intermediate states, such as substrate- and product-bound states. Here we studied the catalytic mechanism of an enzyme, human carbonic anhydrase II (CAII). CA II is a zinc metalloenzyme that catalyzes the reversible interconversion of carbon dioxide (CO2) and water to bicarbonate (HCO3-). To understand the catalytic mechanism of CA II, various intermediate structures were captured during catalytic activity via temperature-controlled X-ray crystallography. The obtained structural information shows how CAII can be one of the fastest enzymes in nature.