Theoretical study of the discrimination between O(2) and CO by myoglobin.
Sigfridsson, Emma and Ryde, Ulf LU
(2002)
In Journal of Inorganic Biochemistry
91(1).
p.101-115
- Abstract
- Combined quantum chemical and molecular mechanics geometry optimisations have been performed on myoglobin without or with O(2) or CO bound to the haem group. The results show that the distal histidine residue is protonated on the N(varepsilon2) atom and forms a hydrogen bond to the haem ligand both in the O(2) and the CO complexes. We have also re-refined the crystal structure of CO-myoglobin by a combined quantum chemical and crystallographic refinement. Thereby, we probably obtain the most accurate available structure of the active site of this complex, showing a Fe-C-O angle of 171 degrees, and Fe-C and C-O bond lengths of 170-171 and 116-117 pm. The resulting structures have been used to calculate the strength of the hydrogen bond... (More)
- Combined quantum chemical and molecular mechanics geometry optimisations have been performed on myoglobin without or with O(2) or CO bound to the haem group. The results show that the distal histidine residue is protonated on the N(varepsilon2) atom and forms a hydrogen bond to the haem ligand both in the O(2) and the CO complexes. We have also re-refined the crystal structure of CO-myoglobin by a combined quantum chemical and crystallographic refinement. Thereby, we probably obtain the most accurate available structure of the active site of this complex, showing a Fe-C-O angle of 171 degrees, and Fe-C and C-O bond lengths of 170-171 and 116-117 pm. The resulting structures have been used to calculate the strength of the hydrogen bond between the distal histidine residue and O(2) or CO in the protein. This amounts to 31-33 kJ/mol for O(2) and 2-3 kJ/mol for CO. The difference in hydrogen-bond strength is 21-22 kJ/mol when corrected for entropy effects. This is slightly larger than the observed discrimination between O(2) or CO by myoglobin, 17 kJ/mol. We have also estimated the strain of the active site inside the protein. It is 2-4 kJ/mol larger for the O(2) complex than for the CO complex, independent of which crystal structure the calculations are based on. Together, these results clearly show that myoglobin discriminates between O(2) and CO mainly by electrostatic interactions, rather than by steric strain. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/109363
- author
- Sigfridsson, Emma
and Ryde, Ulf
LU
- organization
- publishing date
- 2002
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Myoglobin, QC/MM calculations, Quantum refinement, CO/O2 discrimination, Protein strain
- in
- Journal of Inorganic Biochemistry
- volume
- 91
- issue
- 1
- pages
- 101 - 115
- publisher
- Elsevier
- external identifiers
-
- wos:000177141500013
- pmid:12121767
- scopus:0037173553
- ISSN
- 1873-3344
- DOI
- 10.1016/S0162-0134(02)00426-9
- 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
- b60d5bf7-518f-4596-a7af-fd347d6e7e1f (old id 109363)
- date added to LUP
- 2016-04-01 17:01:12
- date last changed
- 2023-01-24 02:30:44
@article{b60d5bf7-518f-4596-a7af-fd347d6e7e1f,
abstract = {{Combined quantum chemical and molecular mechanics geometry optimisations have been performed on myoglobin without or with O(2) or CO bound to the haem group. The results show that the distal histidine residue is protonated on the N(varepsilon2) atom and forms a hydrogen bond to the haem ligand both in the O(2) and the CO complexes. We have also re-refined the crystal structure of CO-myoglobin by a combined quantum chemical and crystallographic refinement. Thereby, we probably obtain the most accurate available structure of the active site of this complex, showing a Fe-C-O angle of 171 degrees, and Fe-C and C-O bond lengths of 170-171 and 116-117 pm. The resulting structures have been used to calculate the strength of the hydrogen bond between the distal histidine residue and O(2) or CO in the protein. This amounts to 31-33 kJ/mol for O(2) and 2-3 kJ/mol for CO. The difference in hydrogen-bond strength is 21-22 kJ/mol when corrected for entropy effects. This is slightly larger than the observed discrimination between O(2) or CO by myoglobin, 17 kJ/mol. We have also estimated the strain of the active site inside the protein. It is 2-4 kJ/mol larger for the O(2) complex than for the CO complex, independent of which crystal structure the calculations are based on. Together, these results clearly show that myoglobin discriminates between O(2) and CO mainly by electrostatic interactions, rather than by steric strain.}},
author = {{Sigfridsson, Emma and Ryde, Ulf}},
issn = {{1873-3344}},
keywords = {{Myoglobin; QC/MM calculations; Quantum refinement; CO/O2 discrimination; Protein strain}},
language = {{eng}},
number = {{1}},
pages = {{101--115}},
publisher = {{Elsevier}},
series = {{Journal of Inorganic Biochemistry}},
title = {{Theoretical study of the discrimination between O(2) and CO by myoglobin.}},
url = {{https://lup.lub.lu.se/search/files/135490553/48_myocq.pdf}},
doi = {{10.1016/S0162-0134(02)00426-9}},
volume = {{91}},
year = {{2002}},
}