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Spectroscopic Description of the E(1) State of Mo Nitrogenase Based on Mo and Fe X-ray Absorption and Mössbauer Studies
[Image: see text] Mo nitrogenase (N2ase) utilizes a two-component protein system, the catalytic MoFe and its electron-transfer partner FeP, to reduce atmospheric dinitrogen (N(2)) to ammonia (NH(3)). The FeMo cofactor contained in the MoFe protein serves as the catalytic center for this reaction and...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2019
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6751781/ https://www.ncbi.nlm.nih.gov/pubmed/31441651 http://dx.doi.org/10.1021/acs.inorgchem.9b01951 |
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author | Van Stappen, Casey Davydov, Roman Yang, Zhi-Yong Fan, Ruixi Guo, Yisong Bill, Eckhard Seefeldt, Lance C. Hoffman, Brian M. DeBeer, Serena |
author_facet | Van Stappen, Casey Davydov, Roman Yang, Zhi-Yong Fan, Ruixi Guo, Yisong Bill, Eckhard Seefeldt, Lance C. Hoffman, Brian M. DeBeer, Serena |
author_sort | Van Stappen, Casey |
collection | PubMed |
description | [Image: see text] Mo nitrogenase (N2ase) utilizes a two-component protein system, the catalytic MoFe and its electron-transfer partner FeP, to reduce atmospheric dinitrogen (N(2)) to ammonia (NH(3)). The FeMo cofactor contained in the MoFe protein serves as the catalytic center for this reaction and has long inspired model chemistry oriented toward activating N(2). This field of chemistry has relied heavily on the detailed characterization of how Mo N2ase accomplishes this feat. Understanding the reaction mechanism of Mo N2ase itself has presented one of the most challenging problems in bioinorganic chemistry because of the ephemeral nature of its catalytic intermediates, which are difficult, if not impossible, to singly isolate. This is further exacerbated by the near necessity of FeP to reduce native MoFe, rendering most traditional means of selective reduction inept. We have now investigated the first fundamental intermediate of the MoFe catalytic cycle, E(1), as prepared both by low-flux turnover and radiolytic cryoreduction, using a combination of Mo Kα high-energy-resolution fluorescence detection and Fe K-edge partial-fluorescence-yield X-ray absorption spectroscopy techniques. The results demonstrate that the formation of this state is the result of an Fe-centered reduction and that Mo remains redox-innocent. Furthermore, using Fe X-ray absorption and (57)Fe Mössbauer spectroscopies, we correlate a previously reported unique species formed under cryoreducing conditions to the natively formed E(1) state through annealing, demonstrating the viability of cryoreduction in studying the catalytic intermediates of MoFe. |
format | Online Article Text |
id | pubmed-6751781 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-67517812019-09-24 Spectroscopic Description of the E(1) State of Mo Nitrogenase Based on Mo and Fe X-ray Absorption and Mössbauer Studies Van Stappen, Casey Davydov, Roman Yang, Zhi-Yong Fan, Ruixi Guo, Yisong Bill, Eckhard Seefeldt, Lance C. Hoffman, Brian M. DeBeer, Serena Inorg Chem [Image: see text] Mo nitrogenase (N2ase) utilizes a two-component protein system, the catalytic MoFe and its electron-transfer partner FeP, to reduce atmospheric dinitrogen (N(2)) to ammonia (NH(3)). The FeMo cofactor contained in the MoFe protein serves as the catalytic center for this reaction and has long inspired model chemistry oriented toward activating N(2). This field of chemistry has relied heavily on the detailed characterization of how Mo N2ase accomplishes this feat. Understanding the reaction mechanism of Mo N2ase itself has presented one of the most challenging problems in bioinorganic chemistry because of the ephemeral nature of its catalytic intermediates, which are difficult, if not impossible, to singly isolate. This is further exacerbated by the near necessity of FeP to reduce native MoFe, rendering most traditional means of selective reduction inept. We have now investigated the first fundamental intermediate of the MoFe catalytic cycle, E(1), as prepared both by low-flux turnover and radiolytic cryoreduction, using a combination of Mo Kα high-energy-resolution fluorescence detection and Fe K-edge partial-fluorescence-yield X-ray absorption spectroscopy techniques. The results demonstrate that the formation of this state is the result of an Fe-centered reduction and that Mo remains redox-innocent. Furthermore, using Fe X-ray absorption and (57)Fe Mössbauer spectroscopies, we correlate a previously reported unique species formed under cryoreducing conditions to the natively formed E(1) state through annealing, demonstrating the viability of cryoreduction in studying the catalytic intermediates of MoFe. American Chemical Society 2019-08-23 2019-09-16 /pmc/articles/PMC6751781/ /pubmed/31441651 http://dx.doi.org/10.1021/acs.inorgchem.9b01951 Text en Copyright © 2019 American Chemical Society This is an open access article published under a Creative Commons Attribution (CC-BY) License (http://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html) , which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. |
spellingShingle | Van Stappen, Casey Davydov, Roman Yang, Zhi-Yong Fan, Ruixi Guo, Yisong Bill, Eckhard Seefeldt, Lance C. Hoffman, Brian M. DeBeer, Serena Spectroscopic Description of the E(1) State of Mo Nitrogenase Based on Mo and Fe X-ray Absorption and Mössbauer Studies |
title | Spectroscopic
Description of the E(1) State of Mo Nitrogenase Based on
Mo and Fe X-ray Absorption and Mössbauer Studies |
title_full | Spectroscopic
Description of the E(1) State of Mo Nitrogenase Based on
Mo and Fe X-ray Absorption and Mössbauer Studies |
title_fullStr | Spectroscopic
Description of the E(1) State of Mo Nitrogenase Based on
Mo and Fe X-ray Absorption and Mössbauer Studies |
title_full_unstemmed | Spectroscopic
Description of the E(1) State of Mo Nitrogenase Based on
Mo and Fe X-ray Absorption and Mössbauer Studies |
title_short | Spectroscopic
Description of the E(1) State of Mo Nitrogenase Based on
Mo and Fe X-ray Absorption and Mössbauer Studies |
title_sort | spectroscopic
description of the e(1) state of mo nitrogenase based on
mo and fe x-ray absorption and mössbauer studies |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6751781/ https://www.ncbi.nlm.nih.gov/pubmed/31441651 http://dx.doi.org/10.1021/acs.inorgchem.9b01951 |
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