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Quantum chemical calculations of the reorganization energy of blue- copper proteins

Olsson, Mats H M LU ; Ryde, Ulf LU and Roos, Björn O. LU (1998) In Protein Science 7(12). p.2659-2668
Abstract

The inner-sphere reorganization energy for several copper complexes related to the active site in blue-copper protein has been calculated with the density functional B3LYP method. The best model of the blue-copper proteins, Cu(Im)2(SCH3)(S(CH'3)2)(0/+), has a self-exchange inner-sphere reorganization energy of 62 kJ/mol, which is at least 120 kJ/mol lower than for Cu(H2O)(+/2+)/4 This lowering of the reorganization energy is caused by the soft ligands in the blue-copper site, especially the cysteine thiolate and the methionine thioether groups. Soft ligands both make the potential surfaces of the complexes flatter and give rise to oxidized structures that are quite close to a... (More)

The inner-sphere reorganization energy for several copper complexes related to the active site in blue-copper protein has been calculated with the density functional B3LYP method. The best model of the blue-copper proteins, Cu(Im)2(SCH3)(S(CH'3)2)(0/+), has a self-exchange inner-sphere reorganization energy of 62 kJ/mol, which is at least 120 kJ/mol lower than for Cu(H2O)(+/2+)/4 This lowering of the reorganization energy is caused by the soft ligands in the blue-copper site, especially the cysteine thiolate and the methionine thioether groups. Soft ligands both make the potential surfaces of the complexes flatter and give rise to oxidized structures that are quite close to a tetrahedron (rather than tetragonal). Approximately half of the reorganization energy originates from changes in the copper-ligand bond lengths and half of this contribution comes from the Cu-S(Cys) bond. A tetragonal site, which is present in the rhombic type 1 blue-copper proteins, has a slightly higher (16 kJ/mol) inner-sphere reorganization energy than a trigonal site, present in the axial type I copper proteins. A site with the methionine ligand replaced by an amide group, as in stellacyanin, has an even higher reorganization energy, about 90 kJ/mol.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
B3LYP method, Blue-copper proteins, Entatic state theory, Induced-rack theory, Reorganization energy
in
Protein Science
volume
7
issue
12
pages
10 pages
publisher
The Protein Society
external identifiers
  • scopus:0031700045
ISSN
0961-8368
DOI
10.1002/pro.5560071220
language
English
LU publication?
yes
id
b5fcad75-dee1-49a5-be75-1e03028af8ab
date added to LUP
2017-02-04 11:38:52
date last changed
2017-06-19 16:21:02
@article{b5fcad75-dee1-49a5-be75-1e03028af8ab,
  abstract     = {<p>The inner-sphere reorganization energy for several copper complexes related to the active site in blue-copper protein has been calculated with the density functional B3LYP method. The best model of the blue-copper proteins, Cu(Im)<sub>2</sub>(SCH<sub>3</sub>)(S(CH'3)<sub>2</sub>)(0/+), has a self-exchange inner-sphere reorganization energy of 62 kJ/mol, which is at least 120 kJ/mol lower than for Cu(H<sub>2</sub>O)(+/2+)/<sub>4</sub> This lowering of the reorganization energy is caused by the soft ligands in the blue-copper site, especially the cysteine thiolate and the methionine thioether groups. Soft ligands both make the potential surfaces of the complexes flatter and give rise to oxidized structures that are quite close to a tetrahedron (rather than tetragonal). Approximately half of the reorganization energy originates from changes in the copper-ligand bond lengths and half of this contribution comes from the Cu-S(Cys) bond. A tetragonal site, which is present in the rhombic type 1 blue-copper proteins, has a slightly higher (16 kJ/mol) inner-sphere reorganization energy than a trigonal site, present in the axial type I copper proteins. A site with the methionine ligand replaced by an amide group, as in stellacyanin, has an even higher reorganization energy, about 90 kJ/mol.</p>},
  author       = {Olsson, Mats H M and Ryde, Ulf and Roos, Björn O.},
  issn         = {0961-8368},
  keyword      = {B3LYP method,Blue-copper proteins,Entatic state theory,Induced-rack theory,Reorganization energy},
  language     = {eng},
  number       = {12},
  pages        = {2659--2668},
  publisher    = {The Protein Society},
  series       = {Protein Science},
  title        = {Quantum chemical calculations of the reorganization energy of blue- copper proteins},
  url          = {http://dx.doi.org/10.1002/pro.5560071220},
  volume       = {7},
  year         = {1998},
}