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On the significance of hydrogen bonds for the discrimination between CO and O2 by myoglobin

Sigfridsson, Emma LU and Ryde, Ulf LU (1999) In Journal of Biological Inorganic Chemistry 4(1). p.99-110
Abstract

Quantum chemical geometry optimisations have been performed on realistic models of the active site of myoglobin using density functional methods. The energy of the hydrogen bond between the distal histidine residue and CO or O2 has been estimated to be 8 kJ/mol and 32 kJ/mol, respectively. This 24 k J/mol energy difference accounts for most of the discrimination between CO and O2 by myoglobin (about 17 kJ/mol). Thus, steric effects seem to be of minor importance for this discrimination. The Fe-C and C-O vibrational frequencies of CO-myoglobin have also been studied and the results indicate that CO forms hydrogen bonds to either the distal histidine residue or a water molecule during normal conditions. We have made... (More)

Quantum chemical geometry optimisations have been performed on realistic models of the active site of myoglobin using density functional methods. The energy of the hydrogen bond between the distal histidine residue and CO or O2 has been estimated to be 8 kJ/mol and 32 kJ/mol, respectively. This 24 k J/mol energy difference accounts for most of the discrimination between CO and O2 by myoglobin (about 17 kJ/mol). Thus, steric effects seem to be of minor importance for this discrimination. The Fe-C and C-O vibrational frequencies of CO-myoglobin have also been studied and the results indicate that CO forms hydrogen bonds to either the distal histidine residue or a water molecule during normal conditions. We have made several attempts to optimize structures with the deprotonated nitrogen atom of histidine directed towards CO. However, all such structures lead to unfavourable interactions between the histidine and CO, and to ν(CO) frequencies higher than those observed experimentally.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
CO/O discrimination, Hydrogen bond, Myoglobin, Quantum chemical calculations, Vibrational frequencies
in
Journal of Biological Inorganic Chemistry
volume
4
issue
1
pages
12 pages
publisher
Springer
external identifiers
  • scopus:0032957265
ISSN
0949-8257
DOI
10.1007/s007750050293
language
English
LU publication?
yes
id
8dfd1b38-f027-46a0-8707-ba8dc8d7b3f0
date added to LUP
2017-02-04 11:42:27
date last changed
2017-06-16 13:40:53
@article{8dfd1b38-f027-46a0-8707-ba8dc8d7b3f0,
  abstract     = {<p>Quantum chemical geometry optimisations have been performed on realistic models of the active site of myoglobin using density functional methods. The energy of the hydrogen bond between the distal histidine residue and CO or O<sub>2</sub> has been estimated to be 8 kJ/mol and 32 kJ/mol, respectively. This 24 k J/mol energy difference accounts for most of the discrimination between CO and O<sub>2</sub> by myoglobin (about 17 kJ/mol). Thus, steric effects seem to be of minor importance for this discrimination. The Fe-C and C-O vibrational frequencies of CO-myoglobin have also been studied and the results indicate that CO forms hydrogen bonds to either the distal histidine residue or a water molecule during normal conditions. We have made several attempts to optimize structures with the deprotonated nitrogen atom of histidine directed towards CO. However, all such structures lead to unfavourable interactions between the histidine and CO, and to ν(CO) frequencies higher than those observed experimentally.</p>},
  author       = {Sigfridsson, Emma and Ryde, Ulf},
  issn         = {0949-8257},
  keyword      = {CO/O discrimination,Hydrogen bond,Myoglobin,Quantum chemical calculations,Vibrational frequencies},
  language     = {eng},
  number       = {1},
  pages        = {99--110},
  publisher    = {Springer},
  series       = {Journal of Biological Inorganic Chemistry},
  title        = {On the significance of hydrogen bonds for the discrimination between CO and O<sub>2</sub> by myoglobin},
  url          = {http://dx.doi.org/10.1007/s007750050293},
  volume       = {4},
  year         = {1999},
}