Reaction Mechanism for CO Reduction by Mo-Nitrogenase Studied by QM/MM.
Inorg Chem
; 63(34): 15951-15963, 2024 Aug 26.
Article
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| MEDLINE
| ID: mdl-39141025
ABSTRACT
We have studied the conversion of two molecules of carbon monoxide to ethylene catalyzed by nitrogenase. We start from a recent crystal structure showing the binding of two carbon monoxide molecules to nitrogenase and employ the combined quantum mechanics and molecular mechanics approach. Our results indicate that the reaction is possible only if S2B dissociates as H2S (i.e., the charge of the FeMo cluster remains the same as in the E0 state, indicating that the Fe ions are formally reduced two steps when CO binds). Eight electrons and protons are needed for the reaction, and our mechanism suggests that the first four bind alternatively to the two carbon atoms. The C-C bond formation takes place already after the first protonation (in the E3 state). The next two protons bind to the same O atom, which then dissociates as water. In the same state (E8), the second C-O bond is cleaved, forming the ethylene product. The last two electrons and protons are used to form a water molecule that can be exchanged by S2B or by two CO molecules to start a new reaction cycle.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Inorg Chem
Año:
2024
Tipo del documento:
Article
País de afiliación:
Suecia
Pais de publicación:
Estados Unidos