On the Possibility of Uphill Intramolecular Electron Transfer in Multicopper Oxidases: Electrochemical and Quantum Chemical Study of Bilirubin Oxidase

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

The catalytic cycle of multicopper oxidases (MCOs) involves intramolecular electron transfer (IET) from the Cu-T1 copper ion, which is the primary site of the one-electron oxidations of the substrate, to the trinuclear copper cluster (TNC), which is the site of the four-electron reduction of dioxygen to water. In this study we report a detailed characterization of the kinetic and electrochemical properties of bilirubin oxidase (BOx) a member of the MCO family. The experimental results strongly indicate that under certain conditions, e.g. in alkaline solutions, the IET can be the rate-limiting step in the BOx catalytic cycle. The data also suggest that one of the catalytically relevant intermediates (most likely characterized by an intermediate oxidation state of the TNC) formed during the catalytic cycle of BOx has a redox potential close to 0.4 V, indicating an uphill IET process from the T1 copper site (0.7 V) to the Cu-T23. These suggestions are supported by calculations of the IET rate, based on the experimentally observed Gibbs free energy change and theoretical estimates of reorganization energy obtained by combined quantum and molecular mechanical (QM/MM) calculations.

Detaljer

Författare
  • Sergey Shleev
  • Viktor Andoralov
  • Magnus Falk
  • Curt Reimann
  • Tautgirdas Ruzgas
  • Martin Srnec
  • Ulf Ryde
  • Lubomir Rulisek
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Biokemi och molekylärbiologi
  • Teoretisk kemi

Nyckelord

Originalspråkengelska
Sidor (från-till)1524-1540
TidskriftElectroanalysis
Volym24
Utgåva nummer7
StatusPublished - 2012
PublikationskategoriForskning
Peer review utfördJa

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