Inhibition of nitrogenase by oxygen in marine cyanobacteria controls the global nitrogen and oxygen cycles

Autor: Berman-Frank, I., Chen, Y.-B., Gerchman, Y., Dismukes, G. C., Falkowski, P. G.
Přispěvatelé: EGU, Publication, Institute of Marine and Coastal Science, Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers), Faculty of Life Sciences, Bar-Ilan University [Israël], Princeton Environmental Institute [Princeton University] (PEI), Princeton University, Department of Geological Sciences
Jazyk: angličtina
Rok vydání: 2005
Předmět:
Zdroj: Biogeosciences Discussions
Biogeosciences Discussions, European Geosciences Union, 2005, 2 (2), pp.261-273
ISSN: 1810-6277
1810-6285
Popis: International audience; Cyanobacterial N2-fixation supplies the vast majority of biologically accessible inorganic nitrogen to nutrient-poor aquatic ecosystems. The process, catalyzed by the heterodimeric protein complex, nitrogenase, is thought to predate that of oxygenic photosynthesis. Remarkably, while the enzyme plays such a critical role in Earth's biogeochemical cycles, the activity of nitrogenase in cyanobacteria is markedly inhibited in vivo at a post-translational level by the concentration of O2 in the contemporary atmosphere leading to metabolic and biogeochemical inefficiency in N2 fixation. We illustrate this crippling effect with data from Trichodesmium spp. an important contributor of "new nitrogen" to the world's subtropical and tropical oceans. The enzymatic inefficiency of nitrogenase imposes a major elemental taxation on diazotrophic cyanobacteria both in the costs of protein synthesis and for scarce trace elements, such as iron. This restriction has, in turn, led to a global limitation of fixed nitrogen in the contemporary oceans and provides a strong biological control on the upper bound of oxygen concentration in Earth's atmosphere.
Databáze: OpenAIRE
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