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

doi:10.1021/acs.inorgchem.9b01951

Title: Spectroscopic Description of the E ₁ State of Mo Nitrogenase Based on Mo and Fe X-ray Absorption and Mössbauer Studies

Abstract

Mo nitrogenase (N_2ase) utilizes a two-component protein system, the catalytic MoFe and its electron-transfer partner FeP, to reduce atmospheric dinitrogen (N₂) to ammonia (NH₃). 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 N₂. This field of chemistry has relied heavily on the detailed characterization of how Mo N_2ase accomplishes this feat. Understanding the reaction mechanism of Mo N_2ase 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, E₁, 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 redoxinnocent. Furthermore, using Fe X-ray absorption and ⁵⁷Fe Mössbauer spectroscopies, we correlate amore »« less

Authors:

^[1]; Davydov, Roman ^[2];

^[3]; Fan, Ruixi ^[4];

^[4];

^[1];

^[3];

^[2];

^[1]

Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34−36, 45470 Mülheim an der Ruhr, Germany
Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States

Publication Date:: Fri Aug 23 00:00:00 EDT 2019

Research Org.:: Max Planck Society, Mülheim (Germany); Utah State Univ., Logan, UT (United States); Stanford Univ., CA (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES); National Institutes of Health (NIH); National Science Foundation (NSF)

OSTI Identifier:: 1558699

Alternate Identifier(s):: OSTI ID: 1562298

Grant/Contract Number:: DESC0010687; AC02-76SF00515; SC0010687; GM111097; CHE1654060

Resource Type:: Published Article

Journal Name:: Inorganic Chemistry

Additional Journal Information:: Journal Name: Inorganic Chemistry Journal Volume: 58 Journal Issue: 18; Journal ID: ISSN 0020-1669

Publisher:: American Chemical Society

Country of Publication:: United States

Language:: English

Subject:: 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats


                    Van Stappen, Casey, Davydov, Roman, Yang, Zhi-Yong, Fan, Ruixi, Guo, Yisong, Bill, Eckhard, Seefeldt, Lance C., Hoffman, Brian M., and DeBeer, Serena. Spectroscopic Description of the E 1 State of Mo Nitrogenase Based on Mo and Fe X-ray Absorption and Mössbauer Studies.  United States: N. p., 2019. 
Web.  doi:10.1021/acs.inorgchem.9b01951.

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                    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.  United States.  https://doi.org/10.1021/acs.inorgchem.9b01951

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                    Van Stappen, Casey, Davydov, Roman, Yang, Zhi-Yong, Fan, Ruixi, Guo, Yisong, Bill, Eckhard, Seefeldt, Lance C., Hoffman, Brian M., and DeBeer, Serena. Fri .  
"Spectroscopic Description of the E 1 State of Mo Nitrogenase Based on Mo and Fe X-ray Absorption and Mössbauer Studies".  United States.  https://doi.org/10.1021/acs.inorgchem.9b01951.

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@article{osti_1558699,

  title        = {Spectroscopic Description of the E 1 State of Mo Nitrogenase Based on Mo and Fe X-ray Absorption and Mössbauer Studies},

  author       = {Van Stappen, Casey and Davydov, Roman and Yang, Zhi-Yong and Fan, Ruixi and Guo, Yisong and Bill, Eckhard and Seefeldt, Lance C. and Hoffman, Brian M. and DeBeer, Serena},

  abstractNote = {Mo nitrogenase (N2ase) utilizes a two-component protein system, the catalytic MoFe and its electron-transfer partner FeP, to reduce atmospheric dinitrogen (N2) to ammonia (NH3). 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 N2. 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, E1, 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 redoxinnocent. Furthermore, using Fe X-ray absorption and 57Fe Mössbauer spectroscopies, we correlate a previously reported unique species formed under cryoreducing conditions to the natively formed E1 state through annealing, demonstrating the viability of cryoreduction in studying the catalytic intermediates of MoFe.},

  doi          = {10.1021/acs.inorgchem.9b01951},

  journal      = {Inorganic Chemistry},

  number       = 18,

  volume       = 58,

  place        = {United States},

  year         = {Fri Aug 23 00:00:00 EDT 2019},

  month        = {Fri Aug 23 00:00:00 EDT 2019}

}

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Cited by: 23 works

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Figures / Tables:

Scheme 1: Current Proposed Relationship between the Previously Observed Natively Reduced (M^R) and Cryoreduced (M^I) Species Formed at the FeMoco Cluster

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Works referencing / citing this record:

Computational Investigations of the Chemical Mechanism of the Enzyme Nitrogenase
journal, January 2020

Dance, Ian
ChemBioChem, Vol. 21, Issue 12
DOI: 10.1002/cbic.201900636

Pyrene‐Based Noncovalent Immobilization of Nitrogenase on Carbon Surfaces
journal, January 2020

Patel, Janki; Cai, Rong; Milton, Ross
ChemBioChem, Vol. 21, Issue 12
DOI: 10.1002/cbic.201900697

A model for dinitrogen binding in the E ₄ state of nitrogenase
journal, January 2019

Thorhallsson, Albert Th.; Benediktsson, Bardi; Bjornsson, Ragnar
Chemical Science, Vol. 10, Issue 48
DOI: 10.1039/c9sc03610e

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Title: Spectroscopic Description of the E 1 State of Mo Nitrogenase Based on Mo and Fe X-ray Absorption and Mössbauer Studies

Abstract

Citation Formats

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