SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Ryde Ulf) ;pers:(Solomon Edward I.)"

Sökning: WFRF:(Ryde Ulf) > Solomon Edward I.

  • Resultat 1-3 av 3
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Chalupsky, Jakub, et al. (författare)
  • Multireference ab initio calculations on reaction intermediates of the multicopper oxidases
  • 2006
  • Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 1520-510X .- 0020-1669. ; 45:26, s. 11051-11059
  • Tidskriftsartikel (refereegranskat)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.
  •  
2.
  • Ryde, Ulf, et al. (författare)
  • Identification of the peroxy adduct in multicopper oxidases by a combination of computational chemistry and extended X-ray absorption fine-structure measurements
  • 2007
  • Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 129:4, s. 726-727
  • Tidskriftsartikel (refereegranskat)abstract
    • We have developed a computational method that combines extended X-ray absorption fine structure (EXAFS) refinements with the integrated quantum mechanical and molecular mechanics (QM/MM) method. This method allows us to obtain a structure of a metal site inside a protein that is compatible with both EXAFS data and QM calculations (i.e., that is chemically reasonable). Thereby, the QM/MM calculations play the same role as MM in nearly all NMR and crystallographic refinements-EXAFS ensures that the metal-ligand distances are accurate and QM/MM fills in all the other structural data. We have used this method to show that a structure with a peroxide ion in the center of the trinuclear cluster fits experimental EXAFS data better than a structure with the peroxide ion on the side of the cluster for the peroxide adduct of multicopper oxidases.
  •  
3.
  • Vancoillie, Steven, et al. (författare)
  • Multireference Ab Initio Calculations of g tensors for Trinuclear Copper Clusters in Multicopper Oxidases.
  • 2010
  • Ingår i: The Journal of Physical Chemistry Part B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 114:22, s. 7692-7702
  • Tidskriftsartikel (refereegranskat)abstract
    • EPR spectroscopy has proven to be an indispensable tool in elucidating the structure of metal sites in proteins. In recent years, experimental EPR data have been complemented by theoretical calculations, which have become a standard tool of many quantum chemical packages. However, there have only been a few attempts to calculate EPR g tensors for exchange-coupled systems with more than two spins. In this work, we present a quantum chemical study of structural, electronic, and magnetic properties of intermediates in the reaction cycle of multicopper oxidases and of their inorganic models. All these systems contain three copper(II) ions bridged by hydroxide or O(2-) anions and their ground states are antiferromagnetically coupled doublets. We demonstrate that only multireference methods, such as CASSCF/CASPT2 or MRCI can yield qualitatively correct results (compared to the experimental values) and consider the accuracy of the calculated EPR g tensors as the current benchmark of quantum chemical methods. By decomposing the calculated g tensors into terms arising from interactions of the ground state with the various excited states, the origin of the zero-field splitting is explained. The results of the study demonstrate that a truly quantitative prediction of the g tensors of exchange-coupled systems is a great challenge to contemporary theory. The predictions strongly depend on small energy differences that are difficult to predict with sufficient accuracy by any quantum chemical method that is applicable to systems of the size of our target systems.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-3 av 3
Typ av publikation
tidskriftsartikel (3)
Typ av innehåll
refereegranskat (3)
Författare/redaktör
Ryde, Ulf (3)
Rulisek, Lubomir (3)
Neese, Frank (2)
Chalupsky, Jakub (2)
Pierloot, Kristine (1)
visa fler...
Vancoillie, Steven (1)
Hsiao, Ya-Wen (1)
visa färre...
Lärosäte
Lunds universitet (3)
Språk
Engelska (3)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (3)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy