Examples include both the 8Fe and the 7Fe clusters in nitrogenase.

The nif system is responsible for the clusters in the enzyme nitrogenase.

The enzyme nitrogenase is one of the few enzymes that can catalyze the process.

This includes the oxygen evolving complex and nitrogenase.

Synthesis of nitrogenase is controlled by the nif genes.

A vanadium nitrogenase is used by some nitrogen-fixing micro-organisms, such as Azotobacter.

Azotobacter species have several types of nitrogenase.

This requires mechanisms for nitrogen fixers to protect nitrogenase from oxygen in vivo.

The problem can be solved by genetic engineering to interrupt down-regulation of nitrogenase in response to nitrogen excess.

In this role vanadium replaces more common molybdenum or iron, and gives the nitrogenase slightly different properties.

The basic one is molybdenum-iron nitrogenase.

It was in R. rubrum that, for the first time, post-translational regulation of nitrogenase was demonstrated.

This process occurs at high levels of metabolism during the fixation of nitrogen and, is thought to protect the nitrogenase system from oxygen.

All diazotrophs contain iron-molybdenum or -vanadium nitrogenase systems.

Aerobes-these species require oxygen to grow, yet their nitrogenase is still debilitated if exposed to oxygen.

In PNS bacteria, hydrogen production is due to catalysis by nitrogenase.

Richard Holm's work on mimics of nitrogenase and creation of iron sulfur clusters.

The iron-sulfur clusters are pervasive and include nitrogenase, the enzymes responsible for biological nitrogen fixation.

A further redox couple, which is still more reducing than the bacterial ferredoxins is implicated in the nitrogenase.

An important role in maturation of Mo-Fe nitrogenase plays the so-called P-cluster.

The interplay of the hydrogen-forming enzymes in "Clostridium" is unique with little or no involvement of nitrogenase.

The vesicles serve to limit the diffusion of oxygen, thus assisting the reduction process that is catalysed by the enzyme nitrogenase.

An iron-molybdenum cluster in nitrogenase deftly catalyzes the fixation of N2, a very inert molecule.

These complexes illustrate how N might bind to the metal(s) in nitrogenase and the catalyst for the Haber process.

There is also a special nitrogenase-protective protein called Shethna, which protects nitrogenase and is involved in protecting the cells from oxygen.