Structural Characterization of CO-Inhibited Mo-Nitrogenase by Combined Application of Nuclear Resonance Vibrational Spectroscopy, Extended X-ray Absorption Fine Structure, and Density Functional Theory: New Insights into the Effects of CO Binding and the Role of the Interstitial Atom
The properties of CO-inhibited Azotobader vinelandii (Av) Mo-nitrogenase (Nase) have been examined by the combined application of nuclear resonance vibrational spectroscopy (NRVS), extended X-ray absorption fine structure (EXAFS), and density functional theory (DFT). Dramatic changes in the NRVS are...
| Publicado en: | Journal of the American Chemical Society Vol. 136; no. 45; pp. 15942 - 15955 |
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| Autores principales: | , , , , , , , , , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
11/12/2014
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=99799380&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 99799380 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 11/12/2014 vid: 136 iid: 45 pid: 997 pub: American Chemical Society artinfo: ui: 99799380 10.1021/ja505720m ppf: 15942 ppct: 13 formats: tig: atl: Structural Characterization of CO-Inhibited Mo-Nitrogenase by Combined Application of Nuclear Resonance Vibrational Spectroscopy, Extended X-ray Absorption Fine Structure, and Density Functional Theory: New Insights into the Effects of CO Binding and the Role of the Interstitial Atom aug: au: Scott, Aubrey D. Yan, Lifen George, Simon J. Wang, Honexin Cramer, Stephen P. Pelmenschikov, Vladimir Guo, Yisong Dapper, Christie H. Newton, William E. Yoda, Yoshitaka Tanaka, Yoshihito affil: Department of Chemistry, University of California, Davis, California 95616, United States Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States Institut für Chemie, Technische Universität Berlin, 10623 Berlin, Germany Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States Department of Biochemistry, Virginia Polytechnic Institute & State University, Blacksburg, Virginia 24061, United States Research and Utilization Division, SPring-8/JASRI, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan SR Materials Science Instrumentation Unit, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan su: Nitrogenases Nuclear resonance reactions Vibrational spectra X-ray absorption Density functional theory Interstitial defects Atoms sug: subj: Nitrogenases Nuclear resonance reactions Vibrational spectra X-ray absorption Density functional theory Interstitial defects Atoms ab: The properties of CO-inhibited Azotobader vinelandii (Av) Mo-nitrogenase (Nase) have been examined by the combined application of nuclear resonance vibrational spectroscopy (NRVS), extended X-ray absorption fine structure (EXAFS), and density functional theory (DFT). Dramatic changes in the NRVS are seen under high-CO conditions, especially in a 188 cm mode associated with symmetric breathing of the central cage of the FeMo-cofactor. Similar changes are reproduced with the α-H195Q_ N2ase variant. In the frequency region above 450 cm, additional features are seen that are assigned to Fe-CO bending and stretching modes (confirmed by CO isotope shifts). The EXAFS for wild-type Nase shows evidence for a significant cluster distortion under high-CO conditions, most dramatically in the splitting of the interaction between Mo and the shell of Fe atoms originally at 5.08 A in the resting enzyme. A DFT model with both a terminal - CO and a partially reduced - CHO ligand bound to adjacent Fe sites is consistent with both earlier FT-IR experiments, and the present EXAFS and NRVS observations for the wild-type enzyme. Another DFT model with two terminal CO ligands on the adjacent Fe atoms yields Fe-CO bands consistent with the a-H195Q variant NRVS. The calculations also shed light on the vibrational "shake" modes of the interstitial atom inside the central cage, and their interaction with the Fe-CO modes. Implications for the CO and N reactivity of Nase are discussed. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2014 holdings: @attributes: islocal: N |
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