ISSN:
0020-7608
Keywords:
nitrogenase
;
nitrogen fixation
;
INDO
;
DFT
;
PM3tm
;
Chemistry
;
Theoretical, Physical and Computational Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
We follow the initial activation of the nitrogen molecule at the FeMo cofactor of nitrogenase and subsequently model the hydrogenation of N2 up to the fourth protonation step using the intermediate neglect of differential overlap quantum-chemical model. The results obtained favor a reaction mechanism going through hydrazido intermediates on the 4-Fe surfaces, externally to the FeMo cofactor. Calculations using density functional theory on smaller model systems also support the suggested mechanism over other possible schemes that involve early release of the first molecule of ammonia as a product of the enzymatic reaction. We also demonstrate that dielectric stabilization due to the protein around the cofactor could lower markedly the barrier for the product release as an ammonium ion. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 70: 1159-1168, 1998
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
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