Hydrogenase: A hydrogen-metabolizing enzyme What do the crystal structures tell us about its mode of action?

摘要

Hydrogenases are proteins which metabolize the most simple of chemical compounds, molecular hydrogen, according to the reaction H_2-2H~+ +2e~-. These enzymes are found in many microorganisms of great biotechnological interest such as methanogenic, acetogenic, nitrogen fixing, photosynthetic or sulfate-reducing bacteria. The X-ray structure of a dimeric [NiFe] hydrogenase together with a wealth of biophysical, biochemical and genetic studies have revealed that the large subunit contains the bimetallic [Ni-Fe] active site, with biologically uncommon CO and CN ligands to the iron, whereas the small subunit contains three iron-sulfur clusters.