A. J. Fielding

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Heme enzymes activate oxygen through formation of transient iron-oxo (ferryl) intermediates of the heme iron. A long-standing question has been the nature of the iron-oxygen bond and, in particular, the protonation state. We present neutron structures of the ferric derivative of cytochrome c peroxidase and its ferryl intermediate; these allow direct(More)
Spin labelling is a chemical technique that enables the integration of a molecule containing an unpaired electron into another framework for study. Given the need to understand the structure, dynamics, and conformational changes of biomacromolecules, spin labelling provides a relatively non-intrusive technique and has certain advantages over X-ray(More)
Platinum(ii) complexes of mixed-valent radicals derived from cyclotricatechylene, a macrocyclic tris-dioxolene Platinum(ii) complexes of mixed-valent radicals derived from cyclotricatechylene, a macrocyclic tris-dioxolene. Users may access full items free of charge; copies of full text items generally can be reproduced, displayed or performed and given to(More)
The flavoenzyme monoamine oxidase (MAO) regulates mammalian behavioral patterns by modulating neurotransmitters such as adrenaline and serotonin. The mechanistic basis which underpins this enzyme is far from agreed upon. Reported herein is that the combination of a synthetic flavin and alloxan generates a catalyst system which facilitates biomimetic amine(More)
Classical molecular dynamics (MD) simulations, within the AMBER program package that runs entirely on a CUDA-enabled NVIDIA graphic processing unit (GPU), were employed to study with low computational cost and good quality of the sampling the dynamics of the methane-thiosulfonate spin label (MTSL) attached to the activation loop of the Aurora-A kinase. MD(More)
The understanding of kinase structure is mostly based on protein crystallography, which is limited by the requirement to trap molecules within a crystal lattice. Characterisation of the conformations of the activation loop in solution, are important to enhance the understanding of molecular processes related to diseases and to support the discovery of small(More)
Classical molecular dynamics (MD) simulations, within the AMBER program package that runs entirely on a CUDA-enabled NVIDIA graphic processing unit (GPU), were employed to study with low computational cost the dynamics of the methane-thiosulfonate spin label (MTSL) attached to the activation loop of Aurora-A kinase. MD provided information about the(More)
We report on an example of confined magnetic ions with long spin coherence near room temperature. This was achieved by confining single Mn(2+) spins in colloidal semiconductor quantum dots (QDs) and by dispersing the QDs in a proton-spin free matrix. The controlled suppression of Mn-Mn interactions and minimization of Mn-nuclear spin dipolar interactions(More)
Heterodisulfide reductase (Hdr) is a key enzyme in the energy metabolism of methanogenic archaea. The enzyme catalyzes the reversible reduction of the heterodisulfide (CoM-S-S-CoB) to the thiol coenzymes M (CoM-SH) and B (CoB-SH). Cleavage of CoM-S-S-CoB at an unusual FeS cluster reveals unique substrate chemistry. The cluster is fixed by cysteines of two(More)
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