A Density Functional Theory Investigation on the Mechanism of the Second Half-Reaction of Nitric Oxide Synthase.
Density functional theory methods have been employed to systematically investigate the overall mechanism of the second half-reaction of nitric oxide synthases. The initial heme-bound hydrogen peroxide intermediate previously identified is found to first undergo a simple rotation about its OO peroxi...
| Publicado en: | Journal of the American Chemical Society Vol. 130; no. 11; pp. 3328 - 3335 |
|---|---|
| Autores principales: | , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
3/19/2008
|
| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| Sumario: | Density functional theory methods have been employed to systematically investigate the overall mechanism of the second half-reaction of nitric oxide synthases. The initial heme-bound hydrogen peroxide intermediate previously identified is found to first undergo a simple rotation about its OO peroxide bond. Then, via a "ping-pong" peroxidase-like mechanism the OH proton is transferred back onto the substrate's -NO oxygen then subsequently onto the outer oxygen of the resulting FeOOH species. As a result, O is released as HO with concomitant formation of a compound I-type (FeO) species. Formation of the final citrulline and NO products can then be achieved in one step via a tetrahedral transition structure resulting from direct attack of the FeO moiety at the substrate's guanidinium carbon center. The possible role of alternative mechanisms involving a protonated compound II-type species or an initial transfer of only the NH hydrogen of the NHOH group of N-hydroxy-L-arginine is also discussed. |
|---|