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

Rovaletti, A., Bruschi, M., Moro, G., Cosentino, U., Greco, C., & Ryde, U. (2019). Theoretical Insights into the Aerobic Hydrogenase Activity of Molybdenum–Copper CO Dehydrogenase. INORGANICS, 7(11) [10.3390/inorganics7110135].

Theoretical Insights into the Aerobic Hydrogenase Activity of Molybdenum–Copper CO Dehydrogenase

Rovaletti, Anna
Primo
;
Bruschi, Maurizio;Moro, Giorgio;Cosentino, Ugo;Greco, Claudio
Penultimo
;
2019

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
Articolo in rivista - Articolo scientifico
Scientifica
CO-dehydrogenase, hydrogenase, DFT, QM/MM
English
Rovaletti, A., Bruschi, M., Moro, G., Cosentino, U., Greco, C., & Ryde, U. (2019). Theoretical Insights into the Aerobic Hydrogenase Activity of Molybdenum–Copper CO Dehydrogenase. INORGANICS, 7(11) [10.3390/inorganics7110135].
Rovaletti, A; Bruschi, M; Moro, G; Cosentino, U; Greco, C; Ryde, U
File in questo prodotto:
File Dimensione Formato  
10281-248785.pdf

accesso aperto

Tipologia di allegato: Publisher’s Version (Version of Record, VoR)
Dimensione 1.42 MB
Formato Adobe PDF
1.42 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10281/248785
Citazioni
  • Scopus 3
  • ???jsp.display-item.citation.isi??? 4
Social impact