Azotobacter vinelandii

Azotobacter vinelandii is diazotroph that can fix nitrogen while grown aerobically. It is a genetically tractable system that is used to study nitrogen fixation. These bacteria are easily cultured and grown.

It is a free-living N2 fixer which is known to produce many phytohormones and vitamins in the soil.

The nitrogenase holoenzyme of Azotobacter vinelandii has been characterised via x-ray crystallography in both ADP tetrafluoroaluminate-bound and MgATP-bound states. The enzyme possesses molybdenum iron-sulfido cluster cofactors (FeMoCo) as active sites, each bearing 2 pseudo-cubic iron-sulfido structures.