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Inner-sphere reorganization energy of iron-sulfur clusters studied with theoretical methods

Sigfridsson, Emma; Olsson, Mats H. M. and Ryde, Ulf LU (2001) In Inorganic Chemistry 40(11). p.2509-2519
Abstract
Models of several types of iron-sulfur clusters (e.g., Fe4S4(SCH3)42-/3-/4-) have been studied with the density functional B3LYP method and medium-sized basis sets. In a vacuum, the inner-sphere reorganization energies are 40, 76, 40, 62, 43, and 42 kJ/mol for the rubredoxin, [2Fe-2S] ferredoxin, Rieske, [4Fe-4S] ferredoxin, high-potential iron protein, and desulfoferrodoxin models, respectively. The first two types of clusters were also studied in the protein, where the reorganization energy was approximately halved. This change is caused by the numerous NH‚‚‚SCys hydrogen bonds to the negatively charged iron-sulfur cluster, giving rise to a polar local environment. The reorganization energy of the iron-sulfur clusters is low because the... (More)
Models of several types of iron-sulfur clusters (e.g., Fe4S4(SCH3)42-/3-/4-) have been studied with the density functional B3LYP method and medium-sized basis sets. In a vacuum, the inner-sphere reorganization energies are 40, 76, 40, 62, 43, and 42 kJ/mol for the rubredoxin, [2Fe-2S] ferredoxin, Rieske, [4Fe-4S] ferredoxin, high-potential iron protein, and desulfoferrodoxin models, respectively. The first two types of clusters were also studied in the protein, where the reorganization energy was approximately halved. This change is caused by the numerous NH‚‚‚SCys hydrogen bonds to the negatively charged iron-sulfur cluster, giving rise to a polar local environment. The reorganization energy of the iron-sulfur clusters is low because the iron ions retain the same geometry and coordination number in both oxidation states. Cysteine ligands give approximately the same reorganization energy as imidazole, but they have the advantage of stabilizing a lower coordination number and giving more covalent bonds and therefore more effective electron-transfer paths. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Inorganic Chemistry
volume
40
issue
11
pages
2509 - 2519
publisher
The American Chemical Society
external identifiers
  • scopus:0035926249
ISSN
1520-510X
DOI
10.1021/ic000752u
language
English
LU publication?
yes
id
13200136-e337-4f67-8d15-0882a80418b9 (old id 2275884)
date added to LUP
2012-01-04 11:29:51
date last changed
2018-01-07 05:19:30
@article{13200136-e337-4f67-8d15-0882a80418b9,
  abstract     = {Models of several types of iron-sulfur clusters (e.g., Fe4S4(SCH3)42-/3-/4-) have been studied with the density functional B3LYP method and medium-sized basis sets. In a vacuum, the inner-sphere reorganization energies are 40, 76, 40, 62, 43, and 42 kJ/mol for the rubredoxin, [2Fe-2S] ferredoxin, Rieske, [4Fe-4S] ferredoxin, high-potential iron protein, and desulfoferrodoxin models, respectively. The first two types of clusters were also studied in the protein, where the reorganization energy was approximately halved. This change is caused by the numerous NH‚‚‚SCys hydrogen bonds to the negatively charged iron-sulfur cluster, giving rise to a polar local environment. The reorganization energy of the iron-sulfur clusters is low because the iron ions retain the same geometry and coordination number in both oxidation states. Cysteine ligands give approximately the same reorganization energy as imidazole, but they have the advantage of stabilizing a lower coordination number and giving more covalent bonds and therefore more effective electron-transfer paths.},
  author       = {Sigfridsson, Emma and Olsson, Mats H. M. and Ryde, Ulf},
  issn         = {1520-510X},
  language     = {eng},
  number       = {11},
  pages        = {2509--2519},
  publisher    = {The American Chemical Society},
  series       = {Inorganic Chemistry},
  title        = {Inner-sphere reorganization energy of iron-sulfur clusters studied with theoretical methods},
  url          = {http://dx.doi.org/10.1021/ic000752u},
  volume       = {40},
  year         = {2001},
}