Site-Specific Oxidation State Assignments of the Iron Atoms in the [4Fe:4S]2+/1+/0 States of the Nitrogenase Fe-Protein.
Angew Chem Int Ed Engl
; 58(12): 3894-3897, 2019 03 18.
Article
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| MEDLINE
| ID: mdl-30698901
ABSTRACT
The nitrogenase iron protein (Fe-protein) contains an unusual [4Fe4S] iron-sulphur cluster that is stable in three oxidation states 2+, 1+, and 0. Here, we use spatially resolved anomalous dispersion (SpReAD) refinement to determine oxidation assignments for the individual irons for each state. Additionally, we report the 1.13-Å resolution structure for the ADP bound Fe-protein, the highest resolution Fe-protein structure presently determined. In the dithionite-reduced [4Fe4S]1+ state, our analysis identifies a solvent exposed, delocalized Fe2.5+ pair and a buried Fe2+ pair. We propose that ATP binding by the Fe-protein promotes an internal redox rearrangement such that the solvent-exposed Fe pair becomes reduced, thereby facilitating electron transfer to the nitrogenase molybdenum iron-protein. In the [4Fe4S]0 and [4Fe4S]2+ states, the SpReAD analysis supports oxidation states assignments for all irons in these clusters of Fe2+ and valence delocalized Fe2.5+ , respectively.
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Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Oxidorreductasas
/
Hierro
Idioma:
En
Revista:
Angew Chem Int Ed Engl
Año:
2019
Tipo del documento:
Article
País de afiliación:
Estados Unidos