What does the nitrogenase complex use to fix nitrogen?

The nitrogenase complex is a crucial enzyme system that facilitates the conversion of atmospheric nitrogen gas (N2) into ammonia (NH3), a process known as nitrogen fixation. This enzymatic reaction is particularly important for certain microorganisms and some plants, as they can utilize this fixed nitrogen to synthesize amino acids and nucleotides.

The key element of the nitrogenase complex's operation is its reliance on ATP hydrolysis. The energy derived from ATP is used to power the various conformational changes and electron transfers that are necessary for the reduction of nitrogen gas into ammonia. Specifically, the nitrogenase complex contains two main components: a reductase, which is responsible for transferring electrons, and a nitrogenase enzyme that catalyzes the actual reduction of nitrogen gas. It is during this process that ATP binds to the reductase, and its hydrolysis provides the energy needed for sustaining the activity of the complex.

In contrast, nitrogen gas itself is what is being fixed, but it does not provide the energy necessary for the reaction; rather, it's the substrate for the nitrogenase. Hydrogen gas may play a role in some nitrogen-fixing reactions but is not utilized by nitrogenase to fix nitrogen. Additionally, oxygen serves as an inhibitor for nitrogen fixation in many nitrogen-f