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Multireference ab initio calculations on reaction intermediates of the multicopper oxidases

Chalupsky, Jakub ; Neese, Frank ; Solomon, Edward I. ; Ryde, Ulf LU orcid and Rulisek, Lubomir (2006) In Inorganic Chemistry 45(26). p.11051-11059
Abstract
The multicopper oxidases (MCOs) couple the four-electron reduction of dioxygen to water with four one-electron oxidations of various substrates. Extensive spectroscopic studies have identified several intermediates in the MCO catalytic cycle, but they have not been able to settle the structures of three of the intermediates, viz. the native intermediate (NI), the peroxy intermediate (PI), and the peroxy adduct (PA). The suggested structures have been further refined and characterized by quantum mechanical/molecular mechanical (QM/MM) calculations. In this paper, we try to establish a direct link between theory and experiment, by calculating spectroscopic parameters for these intermediates using multireference wave functions from the... (More)
The multicopper oxidases (MCOs) couple the four-electron reduction of dioxygen to water with four one-electron oxidations of various substrates. Extensive spectroscopic studies have identified several intermediates in the MCO catalytic cycle, but they have not been able to settle the structures of three of the intermediates, viz. the native intermediate (NI), the peroxy intermediate (PI), and the peroxy adduct (PA). The suggested structures have been further refined and characterized by quantum mechanical/molecular mechanical (QM/MM) calculations. In this paper, we try to establish a direct link between theory and experiment, by calculating spectroscopic parameters for these intermediates using multireference wave functions from the multistate CASPT2 and MRDDCI2 methods. Thereby, we have been able to reproduce low-spin ground states (S = 0 or S = 1/2) for all the MCO intermediates, as well as a low-lying (similar to 150 cm(-1)) doublet state and a doublet-quartet energy gap of similar to 780 cm(-1) for the NI. Moreover, we reproduce the zero-field splitting (similar to 70 cm(-1)) of the ground E-2 state in a D-3 symmetric hydroxy-bridged trinuclear Cu(II) model of the NI and obtain a quantitatively correct quartet-doublet splitting (164 cm(-1)) for a mu 3-oxo-bridged trinuclear Cu( II) cluster. All results support the suggestion that the NI has an O-2-atom in the center of the trinuclear cluster, whereas both the PI and PA have an O-2(2-) ion in the center of the cluster, in agreement with the QM/MM results and spectroscopic measurements. (Less)
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; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Inorganic Chemistry
volume
45
issue
26
pages
11051 - 11059
publisher
The American Chemical Society (ACS)
external identifiers
  • wos:000242899400082
  • scopus:33846598076
ISSN
1520-510X
DOI
10.1021/ic0619512
language
English
LU publication?
yes
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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)
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2d432d24-f7bf-43fd-a088-825b9a62af8b (old id 681662)
date added to LUP
2016-04-01 12:24:21
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2020-11-10 02:58:00
@article{2d432d24-f7bf-43fd-a088-825b9a62af8b,
  abstract     = {The multicopper oxidases (MCOs) couple the four-electron reduction of dioxygen to water with four one-electron oxidations of various substrates. Extensive spectroscopic studies have identified several intermediates in the MCO catalytic cycle, but they have not been able to settle the structures of three of the intermediates, viz. the native intermediate (NI), the peroxy intermediate (PI), and the peroxy adduct (PA). The suggested structures have been further refined and characterized by quantum mechanical/molecular mechanical (QM/MM) calculations. In this paper, we try to establish a direct link between theory and experiment, by calculating spectroscopic parameters for these intermediates using multireference wave functions from the multistate CASPT2 and MRDDCI2 methods. Thereby, we have been able to reproduce low-spin ground states (S = 0 or S = 1/2) for all the MCO intermediates, as well as a low-lying (similar to 150 cm(-1)) doublet state and a doublet-quartet energy gap of similar to 780 cm(-1) for the NI. Moreover, we reproduce the zero-field splitting (similar to 70 cm(-1)) of the ground E-2 state in a D-3 symmetric hydroxy-bridged trinuclear Cu(II) model of the NI and obtain a quantitatively correct quartet-doublet splitting (164 cm(-1)) for a mu 3-oxo-bridged trinuclear Cu( II) cluster. All results support the suggestion that the NI has an O-2-atom in the center of the trinuclear cluster, whereas both the PI and PA have an O-2(2-) ion in the center of the cluster, in agreement with the QM/MM results and spectroscopic measurements.},
  author       = {Chalupsky, Jakub and Neese, Frank and Solomon, Edward I. and Ryde, Ulf and Rulisek, Lubomir},
  issn         = {1520-510X},
  language     = {eng},
  number       = {26},
  pages        = {11051--11059},
  publisher    = {The American Chemical Society (ACS)},
  series       = {Inorganic Chemistry},
  title        = {Multireference ab initio calculations on reaction intermediates of the multicopper oxidases},
  url          = {http://dx.doi.org/10.1021/ic0619512},
  doi          = {10.1021/ic0619512},
  volume       = {45},
  year         = {2006},
}