Mechanism of Mo-dependent nitrogenase

Area of Science:

• Biochemistry
• Microbiology
• Biogeochemical Cycles

Background:

• Nitrogen-fixing bacteria are essential for converting atmospheric dinitrogen (N(2)) into ammonia (NH(3)), a key step in the global nitrogen cycle.
• The molybdenum (Mo)-dependent nitrogenase enzyme system is the most studied mechanism for biological nitrogen fixation.

Purpose of the Study:

• To review the current understanding of the nitrogenase-catalyzed reduction of N(2) to NH(3).
• To elucidate the roles of the iron (Fe) protein, MoFe protein, magnesium ATP (MgATP) hydrolysis, and metal cofactors in nitrogen fixation.

Main Methods:

• Literature review of nitrogenase function and mechanism.
• Analysis of structural and biochemical data on nitrogenase components and cofactors.
• Consideration of recent findings on substrate/inhibitor interactions with the FeMo cofactor.

Main Results:

• Nitrogenase activity involves the coordinated action of the Fe protein and MoFe protein.
• Magnesium ATP (MgATP) hydrolysis by the Fe protein provides energy and electrons for catalysis.
• The MoFe protein's metal clusters, including the FeMo cofactor, are central to substrate binding and N(2) reduction.

Conclusions:

• The reviewed knowledge provides a comprehensive overview of the nitrogenase mechanism.
• Understanding nitrogen fixation is critical for agricultural and environmental applications.
• Further research into nitrogenase function can lead to advancements in synthetic nitrogen fixation.