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Title: Structural changes caused by radiation-induced reduction and radiolysis: the effect of X-ray absorbed dose in a fungal multicopper oxidase

Abstract

Radiation-induced reduction, radiolysis of copper sites and the effect of pH value together with the concomitant geometrical distortions of the active centres were analysed in several fungal (C. gallica) laccase structures collected at cryotemperature. This study emphasizes the importance of careful interpretation when the crystallographic structure of a metalloprotein is described. X-ray radiation induces two main effects at metal centres contained in protein crystals: radiation-induced reduction and radiolysis and a resulting decrease in metal occupancy. In blue multicopper oxidases (BMCOs), the geometry of the active centres and the metal-to-ligand distances change depending on the oxidation states of the Cu atoms, suggesting that these alterations are catalytically relevant to the binding, activation and reduction of O{sub 2}. In this work, the X-ray-determined three-dimensional structure of laccase from the basidiomycete Coriolopsis gallica (Cg L), a high catalytic potential BMCO, is described. By combining spectroscopic techniques (UV–Vis, EPR and XAS) and X-ray crystallography, structural changes at and around the active copper centres were related to pH and absorbed X-ray dose (energy deposited per unit mass). Depletion of two of the four active Cu atoms as well as low occupancies of the remaining Cu atoms, together with different conformations of the metal centres, weremore » observed at both acidic pH and high absorbed dose, correlating with more reduced states of the active coppers. These observations provide additional evidence to support the role of flexibility of copper sites during O{sub 2} reduction. This study supports previous observations indicating that interpretations regarding redox state and metal coordination need to take radiation effects explicitly into account.« less

Authors:
 [1];  [2];  [2];  [3]; ;  [1]
  1. Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca, Morelos 62210 (Mexico)
  2. University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom)
  3. University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom)
Publication Date:
OSTI Identifier:
22351258
Resource Type:
Journal Article
Journal Name:
Acta Crystallographica. Section D: Biological Crystallography
Additional Journal Information:
Journal Volume: 68; Journal Issue: Pt 5; Other Information: PMCID: PMC3335286; PMID: 22525754; PUBLISHER-ID: mh5050; OAI: oai:pubmedcentral.nih.gov:3335286; Copyright (c) International Union of Crystallography 2012; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0907-4449
Country of Publication:
Denmark
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ATOMS; COPPER; CRYSTALLOGRAPHY; CRYSTALS; ELECTRON SPIN RESONANCE; FLEXIBILITY; LIGANDS; MASS; PH VALUE; POTENTIALS; RADIATION EFFECTS; RADIOLYSIS; REDUCTION; VALENCE

Citation Formats

De la Mora, Eugenio, Lovett, Janet E., University of Oxford, South Parks Road, Oxford OX1 3RE, EaStCHEM School of Chemistry, Joseph Black Building, The King’s Buildings, Edinburgh EH9 3JJ, Scotland, Blanford, Christopher F., Manchester Interdisciplinary Biocentre, 131 Princess Street, Manchester M1 7DN, Garman, Elspeth F., Valderrama, Brenda, and Rudino-Pinera, Enrique. Structural changes caused by radiation-induced reduction and radiolysis: the effect of X-ray absorbed dose in a fungal multicopper oxidase. Denmark: N. p., 2012. Web. doi:10.1107/S0907444912005343.
De la Mora, Eugenio, Lovett, Janet E., University of Oxford, South Parks Road, Oxford OX1 3RE, EaStCHEM School of Chemistry, Joseph Black Building, The King’s Buildings, Edinburgh EH9 3JJ, Scotland, Blanford, Christopher F., Manchester Interdisciplinary Biocentre, 131 Princess Street, Manchester M1 7DN, Garman, Elspeth F., Valderrama, Brenda, & Rudino-Pinera, Enrique. Structural changes caused by radiation-induced reduction and radiolysis: the effect of X-ray absorbed dose in a fungal multicopper oxidase. Denmark. https://doi.org/10.1107/S0907444912005343
De la Mora, Eugenio, Lovett, Janet E., University of Oxford, South Parks Road, Oxford OX1 3RE, EaStCHEM School of Chemistry, Joseph Black Building, The King’s Buildings, Edinburgh EH9 3JJ, Scotland, Blanford, Christopher F., Manchester Interdisciplinary Biocentre, 131 Princess Street, Manchester M1 7DN, Garman, Elspeth F., Valderrama, Brenda, and Rudino-Pinera, Enrique. 2012. "Structural changes caused by radiation-induced reduction and radiolysis: the effect of X-ray absorbed dose in a fungal multicopper oxidase". Denmark. https://doi.org/10.1107/S0907444912005343.
@article{osti_22351258,
title = {Structural changes caused by radiation-induced reduction and radiolysis: the effect of X-ray absorbed dose in a fungal multicopper oxidase},
author = {De la Mora, Eugenio and Lovett, Janet E. and University of Oxford, South Parks Road, Oxford OX1 3RE and EaStCHEM School of Chemistry, Joseph Black Building, The King’s Buildings, Edinburgh EH9 3JJ, Scotland and Blanford, Christopher F. and Manchester Interdisciplinary Biocentre, 131 Princess Street, Manchester M1 7DN and Garman, Elspeth F. and Valderrama, Brenda and Rudino-Pinera, Enrique},
abstractNote = {Radiation-induced reduction, radiolysis of copper sites and the effect of pH value together with the concomitant geometrical distortions of the active centres were analysed in several fungal (C. gallica) laccase structures collected at cryotemperature. This study emphasizes the importance of careful interpretation when the crystallographic structure of a metalloprotein is described. X-ray radiation induces two main effects at metal centres contained in protein crystals: radiation-induced reduction and radiolysis and a resulting decrease in metal occupancy. In blue multicopper oxidases (BMCOs), the geometry of the active centres and the metal-to-ligand distances change depending on the oxidation states of the Cu atoms, suggesting that these alterations are catalytically relevant to the binding, activation and reduction of O{sub 2}. In this work, the X-ray-determined three-dimensional structure of laccase from the basidiomycete Coriolopsis gallica (Cg L), a high catalytic potential BMCO, is described. By combining spectroscopic techniques (UV–Vis, EPR and XAS) and X-ray crystallography, structural changes at and around the active copper centres were related to pH and absorbed X-ray dose (energy deposited per unit mass). Depletion of two of the four active Cu atoms as well as low occupancies of the remaining Cu atoms, together with different conformations of the metal centres, were observed at both acidic pH and high absorbed dose, correlating with more reduced states of the active coppers. These observations provide additional evidence to support the role of flexibility of copper sites during O{sub 2} reduction. This study supports previous observations indicating that interpretations regarding redox state and metal coordination need to take radiation effects explicitly into account.},
doi = {10.1107/S0907444912005343},
url = {https://www.osti.gov/biblio/22351258}, journal = {Acta Crystallographica. Section D: Biological Crystallography},
issn = {0907-4449},
number = Pt 5,
volume = 68,
place = {Denmark},
year = {Tue May 01 00:00:00 EDT 2012},
month = {Tue May 01 00:00:00 EDT 2012}
}