6OP2
Selenium incorporated FeMo-cofactor of nitrogenase from azotobacter vinelandii at high concentration of selenium
Summary for 6OP2
| Entry DOI | 10.2210/pdb6op2/pdb |
| Descriptor | Nitrogenase molybdenum-iron protein alpha chain, Nitrogenase molybdenum-iron protein beta chain, 3-HYDROXY-3-CARBOXY-ADIPIC ACID, ... (10 entities in total) |
| Functional Keywords | nitrogenase, selenium, femo-cofactor, oxidoreductase |
| Biological source | Azotobacter vinelandii More |
| Total number of polymer chains | 4 |
| Total formula weight | 231186.74 |
| Authors | Arias, R.J.,Rees, D.C. (deposition date: 2019-04-24, release date: 2019-08-14, Last modification date: 2023-10-11) |
| Primary citation | Henthorn, J.T.,Arias, R.J.,Koroidov, S.,Kroll, T.,Sokaras, D.,Bergmann, U.,Rees, D.C.,DeBeer, S. Localized Electronic Structure of Nitrogenase FeMoco Revealed by Selenium K-Edge High Resolution X-ray Absorption Spectroscopy. J.Am.Chem.Soc., 141:13676-13688, 2019 Cited by PubMed Abstract: The size and complexity of Mo-dependent nitrogenase, a multicomponent enzyme capable of reducing dinitrogen to ammonia, have made a detailed understanding of the FeMo cofactor (FeMoco) active site electronic structure an ongoing challenge. Selective substitution of sulfur by selenium in FeMoco affords a unique probe wherein local Fe-Se interactions can be directly interrogated via high-energy resolution fluorescence detected X-ray absorption spectroscopic (HERFD XAS) and extended X-ray absorption fine structure (EXAFS) studies. These studies reveal a significant asymmetry in the electronic distribution of the FeMoco, suggesting a more localized electronic structure picture than is typically assumed for iron-sulfur clusters. Supported by experimental small molecule model data in combination with time dependent density functional theory (TDDFT) calculations, the HERFD XAS data is consistent with an assignment of Fe2/Fe6 as an antiferromagnetically coupled diferric pair. HERFD XAS and EXAFS have also been applied to Se-substituted CO-inhibited MoFe protein, demonstrating the ability of these methods to reveal electronic and structural changes that occur upon substrate binding. These results emphasize the utility of Se HERFD XAS and EXAFS for selectively probing the local electronic and geometric structure of FeMoco. PubMed: 31356071DOI: 10.1021/jacs.9b06988 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.9 Å) |
Structure validation
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