ATP-independent substrate reduction by nitrogenase P-cluster variant

Area of Science:

• Biochemistry
• Bioinorganic Chemistry
• Catalysis

Background:

• Nitrogenase enzymes are crucial for nitrogen fixation.
• The P-cluster typically mediates electron transfer to the active site.
• A variant P*-cluster, composed of paired [Fe(4)S(4)]-like clusters, was investigated.

Purpose of the Study:

• To investigate the catalytic activity of the P*-cluster variant.
• To determine if the P*-cluster can function independently of ATP.
• To explore the potential of P*-cluster for biomimetic catalysis.

Main Methods:

• Utilized cofactor-deficient proteins (ΔnifH, ΔnifBΔnifZ, ΔnifB MoFe protein) to assess P*-cluster activity.
• Employed europium(II) diethylenetriaminepentaacetate [Eu(II)-DTPA] as a strong reductant.
• Monitored substrate reduction reactions including proton, acetylene, ethylene, hydrazine, cyanide, carbon monoxide, and carbon dioxide.

Main Results:

• The P*-cluster demonstrated ATP-independent substrate reduction in the presence of Eu(II)-DTPA.
• Activity correlated with the amount of P*-clusters in cofactor-deficient proteins, confirming its catalytic role.
• The P*-cluster reduced various substrates, including small molecules, to alkanes and alkenes.

Conclusions:

• The P*-cluster is a catalytically active metal center capable of ATP-independent reactions.
• P*-cluster's ability to reduce diverse substrates suggests potential for biomimetic hydrocarbon production.
• This finding opens avenues for developing novel catalysts for industrial applications under ambient conditions.