Format

Send to

Choose Destination
Inorg Chem. 2004 Jun 14;43(12):3715-8.

Linkage isomerism in nitrite reduction by cytochrome cd1 nitrite reductase.

Author information

1
Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia, Athens, Georgia 30602, USA. silaghi@chem.uga.edu

Abstract

Nitrite reduction by cytochrome cd(1) nitrite reductase (cd(1)NIR) is currently accepted to involve coordination of the nitrite nitrogen atom to the ferrous d(1) heme. Here, density functional theory results are reported on the previously unexplored O-binding of nitrite to ferrous and ferric cd(1)NIR. Although the N-isomer (nitro) is energetically favored over the O-nitrite (nitrito), even one single strong hydrogen bond may provide the energy required to put the two isomers on level terms. When hydrogen bonding existent at the cd(1)NIR active site is accounted for in the computational model, the O-nitrite isomer is found to spontaneously protonate and thus yield a ferric-hydroxo species, liberating nitric oxide. An O-nitrite ferrous cd(1)NIR complex appears to be an energetically feasible intermediate for nitrite reduction. O-Coordination would offer an advantage since the end product of nitrite reduction would be a ferric-hydroxo/water complex, rather than the more kinetically inert iron-nitrosyl complex implied by the N-nitrite mechanism.

PMID:
15180427
DOI:
10.1021/ic035403p
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for American Chemical Society
Loading ...
Support Center