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Theoretical insights into the aerobic hydrogenase activity of molybdenum-copper CO dehydrogenase

Rovaletti, Anna ; Bruschi, Maurizio ; Moro, Giorgio ; Cosentino, Ugo ; Greco, Claudio LU and Ryde, Ulf LU orcid (2019) In Inorganics 7(11).
Abstract
The Mo/Cu-dependent CO dehydrogenase from O. carboxidovorans is an enzyme that is able to catalyse CO oxidation to CO2; moreover, it also expresses hydrogenase activity, as it is able to oxidize H2. Here, we have studied the dihydrogen oxidation catalysis by this enzyme using QM/MM calculations. Our results indicate that the equatorial oxo ligand of Mo is the best suited base for catalysis. Moreover, extraction of the first proton from H2 by means of this basic centre leads to the formation of a Mo–OH–CuIH hydride that allows for the stabilization of the copper hydride, otherwise known to be very unstable. In light of our results, two mechanisms for the hydrogenase activity of the enzyme are proposed. The first reactive channel depends on... (More)
The Mo/Cu-dependent CO dehydrogenase from O. carboxidovorans is an enzyme that is able to catalyse CO oxidation to CO2; moreover, it also expresses hydrogenase activity, as it is able to oxidize H2. Here, we have studied the dihydrogen oxidation catalysis by this enzyme using QM/MM calculations. Our results indicate that the equatorial oxo ligand of Mo is the best suited base for catalysis. Moreover, extraction of the first proton from H2 by means of this basic centre leads to the formation of a Mo–OH–CuIH hydride that allows for the stabilization of the copper hydride, otherwise known to be very unstable. In light of our results, two mechanisms for the hydrogenase activity of the enzyme are proposed. The first reactive channel depends on protonation of the sulphur atom of a Cu-bound cysteine residues, which appears to favour the binding and activation of the substrate. The second reactive channel involves a frustrated Lewis pair, formed by the equatorial oxo group bound to Mo and by the copper centre. In this case, no binding of the hydrogen molecule to the Cu center is observed but once H2 enters into the active site, it can be split following a low-energy path. (Less)
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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
CO dehydrogenase, Density functional theory, Dihydrogen, Hydrogenase, Quantum/classical modeling
in
Inorganics
volume
7
issue
11
article number
135
publisher
MDPI AG
external identifiers
  • scopus:85075798988
ISSN
2304-6740
DOI
10.3390/inorganics7110135
language
English
LU publication?
yes
id
b405cdcd-088d-466d-92b6-a3a6211cbd85
date added to LUP
2019-12-16 14:21:47
date last changed
2023-04-10 06:08:38
@article{b405cdcd-088d-466d-92b6-a3a6211cbd85,
  abstract     = {{The Mo/Cu-dependent CO dehydrogenase from O. carboxidovorans is an enzyme that is able to catalyse CO oxidation to CO2; moreover, it also expresses hydrogenase activity, as it is able to oxidize H2. Here, we have studied the dihydrogen oxidation catalysis by this enzyme using QM/MM calculations. Our results indicate that the equatorial oxo ligand of Mo is the best suited base for catalysis. Moreover, extraction of the first proton from H2 by means of this basic centre leads to the formation of a Mo–OH–CuIH hydride that allows for the stabilization of the copper hydride, otherwise known to be very unstable. In light of our results, two mechanisms for the hydrogenase activity of the enzyme are proposed. The first reactive channel depends on protonation of the sulphur atom of a Cu-bound cysteine residues, which appears to favour the binding and activation of the substrate. The second reactive channel involves a frustrated Lewis pair, formed by the equatorial oxo group bound to Mo and by the copper centre. In this case, no binding of the hydrogen molecule to the Cu center is observed but once H2 enters into the active site, it can be split following a low-energy path.}},
  author       = {{Rovaletti, Anna and Bruschi, Maurizio and Moro, Giorgio and Cosentino, Ugo and Greco, Claudio and Ryde, Ulf}},
  issn         = {{2304-6740}},
  keywords     = {{CO dehydrogenase; Density functional theory; Dihydrogen; Hydrogenase; Quantum/classical modeling}},
  language     = {{eng}},
  month        = {{11}},
  number       = {{11}},
  publisher    = {{MDPI AG}},
  series       = {{Inorganics}},
  title        = {{Theoretical insights into the aerobic hydrogenase activity of molybdenum-copper CO dehydrogenase}},
  url          = {{http://dx.doi.org/10.3390/inorganics7110135}},
  doi          = {{10.3390/inorganics7110135}},
  volume       = {{7}},
  year         = {{2019}},
}