Function
Binds to and protects nitrogenase from irreversible exposure to O(2), in what is known as 'conformational protection' (PubMed:7830548, PubMed:7548055, PubMed:10220344, PubMed:26654855). Shifts nitrogenase into an inactive, O(2)-tolerant state. Exists in 2 states, an open oxidized state that binds and protects nitrogenase, and a closed reduced state that probably does not bind nitrogenase; cooperative oxidation of the 2Fe-2S clusters causes the conformation change (PubMed:26654855). Does not protect nitrogenase with the vanadium-iron subunit, not clear if it protects the iron-only nitrogenase (PubMed:7830548).