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Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
Published on: December 4, 2017
Structural and Functional Characterization of Heterologous Nitrogenase Complexes.
Yizhou Li1,2, Sarah M Narehood1,2, Brian D Cook2
1Department of Chemistry, University of California, La Jolla, San Diego, California 92093, United States.
Biochemistry
|July 2, 2026
Summary
Nitrogenase enzyme function is conserved across diverse bacteria. Researchers found that different nitrogenase components (iron protein and molybdenum-iron protein) from distinct species can still work together, retaining significant catalytic activity.
Area of Science:
- Biochemistry
- Structural Biology
- Microbiology
Background:
- Nitrogenase catalyzes essential dinitrogen to ammonia conversion.
- Molybdenum nitrogenase consists of iron protein (FeP) and molybdenum-iron protein (MoFeP).
- Sequence variability exists in FeP and MoFeP across different diazotrophs, questioning functional compatibility.
Purpose of the Study:
- To investigate the functional and structural compatibility of nitrogenase components from distinct species, Azotobacter vinelandii (Av) and Gluconacetobacter diazotrophicus (Gd).
- To understand the structural basis for functional complementation between heterologous nitrogenase pairs.
Main Methods:
- Determined ADP·BeFx-trapped structure of homologous GdFeP-GdMoFeP complex using cryogenic electron microscopy (cryoEM).
- Measured catalytic activities of homologous and heterologous FeP-MoFeP combinations (Gd/Av and Av/Gd).
- Obtained high-resolution cryoEM structures of heterologous GdFeP-AvMoFeP and AvFeP-GdMoFeP complexes.
Main Results:
- Homologous GdFeP-GdMoFeP complex structure is geometrically similar to its Av counterpart.
- Heterologous Gd/Av nitrogenase combinations retained 60-80% of homologous catalytic activities.
- CryoEM structures revealed that functional complementation tolerates significant sequence variation.
Conclusions:
- Nitrogenase functional compatibility is conserved across phylogenetically distinct species.
- Structural conservation of key elements for ATP hydrolysis, electron transfer, and substrate reduction underlies functional complementation.
- This study provides structural insights into the chemomechanical coupling mechanism of nitrogenase.
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