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The reaction mechanism of iron and manganese superoxide dismutases studied by theoretical calculations

Rulisek, Lubomir LU ; Jensen, Kasper LU ; Lundgren, Kristoffer and Ryde, Ulf LU orcid (2006) In Journal of Computational Chemistry 27(12). p.1398-1414
Abstract
We have studied the detailed reaction mechanism of iron and manganese superoxide dismutase with density functional calculations on realistic active-site models, with large basis sets and including solvation, zero-point, and thermal effects. The results indicate that the conversion of O-2(-) to O-2 follows an associative mechanism, with O-2 directly binding to the metal, followed by the protonation of the metal-bound hydroxide ion, and the dissociation of O-3(2). All these reaction steps are exergonic. Likewise, we suggest that the conversion of O-2(-) to H2O2 follows an at least a partly second-sphere pathway. There are small differences in the preferred oxidation and spin states, as well as in the geometries, of Fe and Mn, but these... (More)
We have studied the detailed reaction mechanism of iron and manganese superoxide dismutase with density functional calculations on realistic active-site models, with large basis sets and including solvation, zero-point, and thermal effects. The results indicate that the conversion of O-2(-) to O-2 follows an associative mechanism, with O-2 directly binding to the metal, followed by the protonation of the metal-bound hydroxide ion, and the dissociation of O-3(2). All these reaction steps are exergonic. Likewise, we suggest that the conversion of O-2(-) to H2O2 follows an at least a partly second-sphere pathway. There are small differences in the preferred oxidation and spin states, as well as in the geometries, of Fe and Mn, but these differences have little influence on the energetics, and therefore on the reaction mechanism of the two types of superoxide dismutases. For example, the two metals have very similar reduction potentials in the active-site models, although they differ by 0.7 V in water solution. The reaction mechanisms and spin states seem to have been designed to avoid spin conversions or to facilitate them by employing nearly degenerate spin states. (c) 2006 Wiley Periodicals, Inc. (Less)
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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
superoxide dismutase, iron, manganese, reaction mechanisms
in
Journal of Computational Chemistry
volume
27
issue
12
pages
1398 - 1414
publisher
John Wiley and Sons
external identifiers
  • wos:000239072600014
  • scopus:33747201345
ISSN
1096-987X
DOI
10.1002/jcc.20450
language
English
LU publication?
yes
additional info
The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Theoretical Chemistry (S) (011001039)
id
8f523727-a1b6-47de-9459-20af5fd3b90e (old id 402189)
date added to LUP
2016-04-01 16:51:23
date last changed
2021-09-29 03:56:00
@article{8f523727-a1b6-47de-9459-20af5fd3b90e,
  abstract     = {We have studied the detailed reaction mechanism of iron and manganese superoxide dismutase with density functional calculations on realistic active-site models, with large basis sets and including solvation, zero-point, and thermal effects. The results indicate that the conversion of O-2(-) to O-2 follows an associative mechanism, with O-2 directly binding to the metal, followed by the protonation of the metal-bound hydroxide ion, and the dissociation of O-3(2). All these reaction steps are exergonic. Likewise, we suggest that the conversion of O-2(-) to H2O2 follows an at least a partly second-sphere pathway. There are small differences in the preferred oxidation and spin states, as well as in the geometries, of Fe and Mn, but these differences have little influence on the energetics, and therefore on the reaction mechanism of the two types of superoxide dismutases. For example, the two metals have very similar reduction potentials in the active-site models, although they differ by 0.7 V in water solution. The reaction mechanisms and spin states seem to have been designed to avoid spin conversions or to facilitate them by employing nearly degenerate spin states. (c) 2006 Wiley Periodicals, Inc.},
  author       = {Rulisek, Lubomir and Jensen, Kasper and Lundgren, Kristoffer and Ryde, Ulf},
  issn         = {1096-987X},
  language     = {eng},
  number       = {12},
  pages        = {1398--1414},
  publisher    = {John Wiley and Sons},
  series       = {Journal of Computational Chemistry},
  title        = {The reaction mechanism of iron and manganese superoxide dismutases studied by theoretical calculations},
  url          = {http://dx.doi.org/10.1002/jcc.20450},
  doi          = {10.1002/jcc.20450},
  volume       = {27},
  year         = {2006},
}