Sulfide Protects [FeFe] Hydrogenases From O₂

Area of Science:

• Biochemistry
• Bioenergetics
• Enzymology

Background:

• [FeFe] hydrogenases are crucial enzymes for energy conversion, catalyzing proton reduction and hydrogen oxidation.
• However, their high sensitivity to oxygen limits their practical applications.
• The oxygen-stable inactive H_ox^air state offers a potential solution for enzyme handling.

Purpose of the Study:

• To establish a simple and robust protocol for generating the oxygen-stable inactive H_ox^air state in [FeFe] hydrogenases.
• To demonstrate the applicability of this protocol to different hydrogenase enzymes.

Main Methods:

• High potential inactivation of purified [FeFe] hydrogenases from Desulfovibrio desulfuricans (DdHydAB) and Chlamydomonas reinhardtii.
• Incubation in the presence of sulfide to induce the H_ox^air state.

Main Results:

• A straightforward protocol was developed for forming the H_ox^air state in DdHydAB and C. reinhardtii [FeFe] hydrogenases.
• This method enables the purification and handling of these enzymes under ambient air conditions.
• The protocol relies on sulfide-induced inactivation at high redox potential.

Conclusions:

• The developed protocol provides a feasible method for air-stabilizing [FeFe] hydrogenases.
• This advancement significantly enhances the potential for biotechnological applications of these enzymes.
• The H_ox^air state formation is crucial for overcoming oxygen sensitivity challenges.