Work

Cross‐Coupling of Mo‐ and V‐Nitrogenases Permits Protein‐Mediated Protection from Oxygen Deactivation

Year: 2024

Type: article

Abstract: Nitrogenases catalyze dinitrogen (N2) fixation to ammonia (NH3). While these enzymes are highly sensitive to deactivation by molecular oxygen (O2) they can be produced by obligate aerobes for diazotrophy, necessitating a mechanism by which nitrogenase can be protected from deactivation. In the bacterium Azotobacter vinelandii, one mode of such protection involves an O2‐responsive ferredoxin‐type protein (“Shethna protein II”, or “FeSII”) which is thought to bind with Mo‐dependent nitrogenase's two component proteins (NifH and NifDK) to form a catalytically stalled yet O2‐tolerant tripartite protein complex. This protection mechanism has been reported for Mo‐nitrogenase, however, in vitro assays with V‐nitrogenase suggest that this mechanism is not universal to the three known nitrogenase isoforms. Here we report that the reductase of the V‐nitrogenase (VnfH) can engage in this FeSII‐mediated protection mechanism when cross‐coupled with Mo‐nitrogenase NifDK. Interestingly, the cross‐coupling of the Mo‐nitrogenase reductase NifH with the V‐nitrogenase VnfDGK protein does not yield such protection.

Source: ChemBioChem

DOI: 10.1002/cbic.202400585

Authors: Daniel Ratcliff, G. C. Danielle Sedoh, Ross D. Milton

Institutions: University of Geneva, NCCR Catalysis

Language: English

Topic: Metalloenzymes and iron-sulfur proteins

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

Open Access status: green

Funders: Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, NCCR Catalysis

Award: G6504295074