A Proposed Complete-Cycle Mechanism for Conversion of N2 to NH3 by Mo-Nitrogenase
1School of Chemistry, UNSW Sydney, Sydney, NSW, Australia.
Chembiochem : a European Journal of Chemical Biology
|July 24, 2026
Summary
Nitrogenase converts atmospheric nitrogen (N2) to ammonia (NH3) via the Dance mechanism, involving 40 intermediates and 31 steps. This process activates N2 through a unique capture step, facilitating subsequent hydrogenations to produce NH3.
Area of Science:
- Biochemistry
- Enzymology
- Computational Chemistry
Background:
- Nitrogenase catalyzes the essential conversion of atmospheric nitrogen (N2) to ammonia (NH3) under ambient conditions.
- Understanding this complex enzymatic process is crucial for nitrogen fixation and agricultural applications.
Purpose of the Study:
- To elucidate the detailed chemical mechanism of nitrogenase-catalyzed N2 reduction to NH3.
- To investigate the energy profiles and kinetic barriers of the reaction pathway.
Main Methods:
- Density functional simulations using a large quantum model (483+ atoms).
- Analysis of 40 explicit intermediates and 31 reaction steps.
- Consideration of quantum tunneling and stereochemical factors.
Main Results:
- Discovery of a unique N2 capture step involving activation by hydrogen atoms and formation of Fe-N bonds.
- Detailed description of subsequent hydrogenation steps leading to NH3 formation.
- Identification of bridging S2B retention as a key stereochemical element.
Conclusions:
- The Dance mechanism provides a comprehensive framework for nitrogenase function.
- Favorable geometry and stereochemistry enable efficient N2 reduction.
- Further resolution of kinetic data inconsistencies is required.
Keywords:
density functional calculationshydrogen atom transfernitrogenasesreaction mechanismstransition statesMore Related Videos
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