A protein scaffold enables hydrogen evolution for a Ni-bisdiphosphine complex.

Area of Science:

• Bioinorganic Chemistry
• Biomimetic Catalysis
• Electrocatalysis

Background:

• Hydrogenase enzymes are crucial for biological hydrogen metabolism.
• Developing artificial mimics of hydrogenase is key for sustainable hydrogen production.
• Metalloenzymes offer a platform for designing efficient catalysts.

Purpose of the Study:

• To engineer an artificial metalloenzyme that mimics hydrogenase function.
• To investigate the electrocatalytic hydrogen production capabilities of the artificial enzyme.
• To assess the activity of the artificial enzyme across a range of pH conditions.

Main Methods:

• Assembly of an artificial metalloenzyme via covalent attachment of a nickel complex, [Ni(PN^glycineP)₂]^2-, into a protein scaffold.
• Electrocatalytic testing of the assembled artificial enzyme for hydrogen (H₂) production.
• Comparative analysis with similar nickel complexes, [Ni(PNP)₂]²⁺, lacking the glycine linker.

Main Results:

• The artificial metalloenzyme demonstrated electrocatalytic H₂ production.
• Activity was observed over a broad pH range, from 3.0 to 10.0.
• No electrocatalytic activity was detected for the analogous [Ni(PNP)₂]²⁺ systems.

Conclusions:

• The structured protein scaffold successfully activated the nickel complex for biomimetic hydrogenase activity.
• The artificial metalloenzyme is a robust and efficient catalyst for electrocatalytic hydrogen production.
• The glycine linker in the nickel complex is essential for achieving catalytic function.