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The cupric geometry of blue copper proteins is not strained

Ryde, Ulf LU ; Olsson, Mats H M LU ; Pierloot, Kristine and Roos, Björn O. LU (1996) In Journal of Molecular Biology 261(4). p.586-596
Abstract

The geometry of several realistic models of the metal coordination sphere in the blue copper proteins has been optimised using high-level quantum chemical methods. The results show that the optimal vacuum structure of the Cu(II) models is virtually identical to the crystal structure of oxidised blue copper proteins. For the reduced forms, the optimised structure seems to be more tetrahedral than the one found in the proteins, but the energy difference between the two geometries is less than 5 kJ/mol, i.e. within the error limits of the method. Thus, the results raise strong doubts against hypotheses (entatic state and the induced-rack theory) suggesting that blue copper proteins force the oxidised metal coordination sphere into a... (More)

The geometry of several realistic models of the metal coordination sphere in the blue copper proteins has been optimised using high-level quantum chemical methods. The results show that the optimal vacuum structure of the Cu(II) models is virtually identical to the crystal structure of oxidised blue copper proteins. For the reduced forms, the optimised structure seems to be more tetrahedral than the one found in the proteins, but the energy difference between the two geometries is less than 5 kJ/mol, i.e. within the error limits of the method. Thus, the results raise strong doubts against hypotheses (entatic state and the induced-rack theory) suggesting that blue copper proteins force the oxidised metal coordination sphere into a structure similar to that preferred by Cu(I) in order to minimise the reorganisation energy of the electron transfer reaction. Instead, a small reorganisation energy seems to be reached by an appropriate choice of metal ligands. In particular, the cysteine thiolate ligand appears to be crucial, changing the preferred geometry of the oxidised complexes from square-planar to a more trigonal geometry.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
B3LYP method, Blue copper protein, Entatic state theory, Induced-rack theory, Protein strain
in
Journal of Molecular Biology
volume
261
issue
4
pages
11 pages
publisher
Elsevier
external identifiers
  • scopus:0030606884
ISSN
0022-2836
DOI
10.1006/jmbi.1996.0484
language
English
LU publication?
yes
id
e6b1cce4-bc0a-4992-9494-624a8e72cba5
date added to LUP
2017-02-04 11:31:47
date last changed
2017-06-20 11:00:50
@article{e6b1cce4-bc0a-4992-9494-624a8e72cba5,
  abstract     = {<p>The geometry of several realistic models of the metal coordination sphere in the blue copper proteins has been optimised using high-level quantum chemical methods. The results show that the optimal vacuum structure of the Cu(II) models is virtually identical to the crystal structure of oxidised blue copper proteins. For the reduced forms, the optimised structure seems to be more tetrahedral than the one found in the proteins, but the energy difference between the two geometries is less than 5 kJ/mol, i.e. within the error limits of the method. Thus, the results raise strong doubts against hypotheses (entatic state and the induced-rack theory) suggesting that blue copper proteins force the oxidised metal coordination sphere into a structure similar to that preferred by Cu(I) in order to minimise the reorganisation energy of the electron transfer reaction. Instead, a small reorganisation energy seems to be reached by an appropriate choice of metal ligands. In particular, the cysteine thiolate ligand appears to be crucial, changing the preferred geometry of the oxidised complexes from square-planar to a more trigonal geometry.</p>},
  author       = {Ryde, Ulf and Olsson, Mats H M and Pierloot, Kristine and Roos, Björn O.},
  issn         = {0022-2836},
  keyword      = {B3LYP method,Blue copper protein,Entatic state theory,Induced-rack theory,Protein strain},
  language     = {eng},
  month        = {08},
  number       = {4},
  pages        = {586--596},
  publisher    = {Elsevier},
  series       = {Journal of Molecular Biology},
  title        = {The cupric geometry of blue copper proteins is not strained},
  url          = {http://dx.doi.org/10.1006/jmbi.1996.0484},
  volume       = {261},
  year         = {1996},
}