title: Exploiting orientation-selective DEER: determining molecular structure in systems containing Cu(ii) centres.
abstract: Orientation-selective DEER (Double Electron-Electron Resonance) measurements were conducted on a series of rigid and flexible molecules containing Cu(ii) ions. A system with two rigidly held Cu(ii) ions was afforded by the protein homo-dimer of copper amine oxidase from Arthrobacter globiformis. This system provided experimental DEER data between two Cu(ii) ions with a well-defined distance and relative orientation to assess the accuracy of the methodology. Evaluation of orientation-selective DEER (os DEER) on systems with limited flexibility was probed using a series of porphyrin-based Cu(ii)-nitroxide and Cu(ii)-Cu(ii) model systems of well-defined lengths synthesized for this project. Density functional theory was employed to generate molecular models of the conformers for each porphyrin-based Cu(ii) dimer studied. Excellent agreement was found between DEER traces simulated using these computed conformers and the experimental data. The performance of different parameterised structural models in simulating the experimental DEER data was also investigated. The results of this analysis demonstrate the degree to which the DEER data define the relative orientation of the two Cu(ii) ions and highlight the need to choose a parameterised model that captures the essential features of the flexibility (rotational freedom) of the system being studied.
authors.affiliation: Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK. Christiane.timmel@chem.ox.ac.uk and Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt am Main, Germany.
authors.forename: Alice M
authors.initials: AM
authors.lastname: Bowen
authors.affiliation: Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK. Christiane.timmel@chem.ox.ac.uk.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Jones
authors.affiliation: Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK. Christiane.timmel@chem.ox.ac.uk and SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK.
authors.forename: Janet E
authors.initials: JE
authors.lastname: Lovett
authors.affiliation: Astbury Centre for Structural Molecular Biology, Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Thembanikosi G
authors.initials: TG
authors.lastname: Gaule
authors.affiliation: Astbury Centre for Structural Molecular Biology, Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: McPherson
authors.affiliation: Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK. Christiane.timmel@chem.ox.ac.uk.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Dilworth
authors.affiliation: Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK. Christiane.timmel@chem.ox.ac.uk.
authors.forename: Christiane R
authors.initials: CR
authors.lastname: Timmel
authors.affiliation: Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK. Christiane.timmel@chem.ox.ac.uk and Centre for Advanced Imaging, University of Queensland, St Lucia, QLD 4072, Australia. Jeffrey.harmer@cai.uq.edu.au.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Harmer
mesh_terms: D006631:Amine Oxidase (Copper-Containing) / Q000737:chemistry; D056831:Coordination Complexes / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D011166:Porphyrins / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D011166:Porphyrins; D003300:Copper; D006631:Amine Oxidase (Copper-Containing)