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Metabolic
Diazotrophic bacteria, archaea
Nitrogen Fixation
Reduction of atmospheric N₂ to ammonia by nitrogenase.
Overview
Biological nitrogen fixation converts atmospheric dinitrogen (N₂) to ammonia (NH₃) via the nitrogenase enzyme complex. The reaction requires 16 ATP and 8 electrons per N₂ reduced. Nitrogenase consists of two components: the Fe protein (dinitrogenase reductase) and the MoFe protein (dinitrogenase). The enzyme is extremely oxygen-sensitive, so diazotrophs employ various strategies to protect it.
Cellular Location
Cytoplasm of diazotrophs; root nodules (symbiotic)
Clinical Significance
Essential for the global nitrogen cycle; Haber-Bosch process mimics this industrially; symbiotic Rhizobium-legume associations critical for agriculture.