Hydrogenases are highly active enzymes for producing and consuming hydrogen using cheap and abundant metals like iron and nickel in their active site. In industry, similar efficiency can only be achieved using expensive metals like platinum. However, one obstacle for using hydrogenases in biotechnology is their inactivation by oxygen. [FeFe] hydrogenase, the most active type of hydrogenase, are particularly sensitive. Interestingly, some of these enzymes can be purified in an inactive state, called Hinact, which is oxygen stable. This state can then be reactivated by hydrogen giving a highly active enzyme. In a new study published in the scientific journal Angewandte Chemie Intl. Ed., a team of researchers from Germany, United States and Japan, studied the Hinact state using X-ray crystallography combined with a wide range of spectroscopies and quantum chemical calculations. The researchers discovered a sulfur ligand, “Caught in the Hinact”, at the site where oxygen attacks. This prevents oxygen from binding and protects the enzyme from damage.
Original Publication: Rodríguez-Maciá, P., Galle, L., Bjornsson, R., Lorent, C., Zebger, I., Yoshitaka Yoda, Y., Cramer, S., DeBeer, S., Span, I., Birrell, J. Caught in the Hinact: Crystal Structure and Spectroscopy Reveal a Sulfur Bound to the Active Site of an O2‐stable State of [FeFe] Hydrogenase. Angewandte Chemie Intl. Ed. https://doi.org/10.1002/anie.202005208