Mechanism of protein oxidative damage that is coupled to long-range electron transfer to high-valent haems
| Autor: | Victor L. Davidson, Heather R. Williamson, Zhongxin Ma |
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| Rok vydání: | 2016 |
| Předmět: |
Models
Molecular 0301 basic medicine Cytochrome Heme 010402 general chemistry Photochemistry 01 natural sciences Biochemistry Article Electron Transport 03 medical and health sciences Electron transfer chemistry.chemical_compound Bacterial Proteins Kinetic isotope effect Molecular Biology Paracoccus denitrificans Methionine 030102 biochemistry & molecular biology biology Methionine sulfoxide Sulfoxide Cell Biology Electron transport chain Recombinant Proteins 0104 chemical sciences Solvent chemistry Solvents biology.protein Oxidation-Reduction |
| Zdroj: | Biochemical Journal. 473:1769-1775 |
| ISSN: | 1470-8728 0264-6021 |
| DOI: | 10.1042/bcj20160047 |
| Popis: | In the absence of its substrate, the auto-reduction of the high-valent bis-Fe(IV) state of the dihaem enzyme MauG is coupled to oxidative damage of a methionine residue. Transient kinetic and solvent isotope effect studies reveal that this process occurs via two sequential long-range electron transfer (ET) reactions from methionine to the haems. The first ET is coupled to proton transfer (PT) to the haems from solvent via an ordered water network. The second ET is coupled to PT at the methionine site and occurs during the oxidation of the methionine to a sulfoxide. This process proceeds via Compound I- and Compound II-like haem intermediates. It is proposed that the methionine radical is stabilized by a two-centre three-electron (2c3e) bond. This provides insight into how oxidative damage to proteins may occur without direct contact with a reactive oxygen species, and how that damage can be propagated through the protein. |
| Databáze: | OpenAIRE |
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