Composition and Structure of Nitrogenases

It is interesting that nature has developed dinitrogenases that utilize other metals as alternatives to Mo. Bishop and Premakumar [43] have established that vanadium-iron or iron-only dinitrogenases can function in place of Mo dinitrogenase. In the absence of Mo, the organisms can insert V into dinitrogenase instead of Mo the active site of the enzyme then is at FeVco rather than at FeMoco. Likewise, FeFeco can serve as the all-iron active site. 

Dinitrogenase has been crystallized and its tertiary structure determined by Kim and Rees. [44, 45,46] As indicated, an Fe-Mo unit serves at the active site. Electrons are furnished to this active unit by the Fe enzyme dinitrogenase reductase. The two units together constitute nitrogenase. 

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