FeMo sub-nanoclusters/single atoms for neutral ammonia electrosynthesis
Explore the source record for details and available documents.
99 GENERAL AND MISCELLANEOUS↗
SEARCH · Search NASA
Results for “molybdenum nitrogenase”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Zeolite-Stabilized Di- and Tetranuclear Molybdenum Sulfide Clusters Form Stable Catalytic Hydrogenation Sites
Supercages of faujasite (FAU)-type zeolites serve as a robust scaffold for stabilizing dinuclear (Mo 2 S 4 ) and tetranuclear (Mo 4 S 4 ) molybdenum sulfide clusters. The FAU-encaged Mo 4 S 4 clusters have a distorted cubane structure similar to the FeMo-cofactor in nitrogenase. Both clusters possess one unpaired electron per Mo atom. Additionally, they show identical catalytic activity per sulfide cluster. Their catalytic activity is stable (> 150 h) for ethene hydrogenation, while layered MoS 2 structures deactivate significantly under the same reaction conditions.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Bioavailability of molybdenite to support nitrogen fixation on early Earth by an anoxygenic phototroph
Biological nitrogen fixation, which converts atmospheric dinitrogen to ammonia, is catalyzed mostly by Mo-nitrogenase and is a primary contributor to bioavailable nitrogen on early Earth. Mo-nitrogenase is believed to have evolved during the Archean, despite the extremely low concentration of dissolved Mo. However, it remains unclear whether Mo minerals could serve as a source of Mo to support the prevalence of Mo-nitrogenase on early Earth. Here, in this study, we investigated the bioavailability of molybdenite by incubating it with a metabolically ancient anoxygenic phototroph (Rhodopseudomonas palustris) under anoxic conditions. In the laboratory, R. palustris utilized molybdenum from molybdenite as a cofactor for nitrogen fixation. This bacterium extracted Mo from molybdenite by secreting molybdophores rhodopetrobactin A and B and by expressing Mo transport proteins. Surface-sensitive techniques demonstrated significant changes in surface chemistry of molybdenite after its interaction with cells. These findings provide novel explanations for the prevalence of Mo-nitrogenase on early Earth, with significant implications for nitrogen fixation in modern Mo-deficient environments.
54 ENVIRONMENTAL SCIENCES↗
Specificity of NifEN and VnfEN for the Assembly of Nitrogenase Active Site Cofactors in Azotobacter vinelandii
Biological nitrogen fixation is a complex process involving the nitrogenases. The biosynthesis of an active nitrogenase involves a large number of genes and the coordinated function of their products.
nitrogenase↗