Enigmatic evolution of microbial nitrogen fixation: insights from Earth’s past
Nitrogenase, the key enzyme for biological nitrogen fixation, is an evolutionary singularity, as only one mechanism capable of catalyzing the reduction of atmospheric N2 into fixed nitrogen is known to have evolved.Nitrogenase has three metal isoforms (iron, molybdenum, and vanadium) and is thus con...
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Veröffentlicht in: | Trends in microbiology (Regular ed.) 2024-06, Vol.32 (6), p.554-564 |
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Sprache: | eng |
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Zusammenfassung: | Nitrogenase, the key enzyme for biological nitrogen fixation, is an evolutionary singularity, as only one mechanism capable of catalyzing the reduction of atmospheric N2 into fixed nitrogen is known to have evolved.Nitrogenase has three metal isoforms (iron, molybdenum, and vanadium) and is thus connected and dependent upon biogeochemical cycles for metal availability.Molybdenum is abundant in modern oceans, was very scarce in ancient oceans and remains scarce in modern terrestrial environments. Despite its scarcity, it is proposed that early nitrogenases first utilized Mo-cofactors given its catalytic advantages over abundant Fe.To understand the evolution and diversification of the nitrogen cycle, we must first understand the paleoecological and planetary conditions that give rise to biological nitrogen fixation.
The evolution of nitrogen fixation undoubtedly altered nearly all corners of the biosphere, given the essential role of nitrogen in the synthesis of biomass. To date, there is no unified view on what planetary conditions gave rise to nitrogen fixation or how these conditions have sustained it evolutionarily. Intriguingly, the concentrations of metals that nitrogenases require to function have changed throughout Earth’s history. In this review, we describe the interconnection of the metal and nitrogen cycles with nitrogenase evolution and the importance of ancient ecology in the formation of the modern nitrogen cycle. We argue that exploration of the nitrogen cycle’s deep past will provide insights into humanity’s immediate environmental challenges centered on nitrogen availability. |
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ISSN: | 0966-842X 1878-4380 |
DOI: | 10.1016/j.tim.2023.03.011 |