Catalytic cycles for the reduction of [UO2]2+ by cytochrome c7 proteins proposed from DFT calculations

Mahesh Sundararajan, Andrew J. Campbell, Ian H. Hillier

    Research output: Contribution to journalArticlepeer-review

    Abstract

    The mechanism of the reduction of the hydrated uranyl cation, [UO 2]2+, by the cytochromes G. sulfurreducens and D. acetoxidans has been studied using density functional theory calculations. We propose that the initial electron transfer step from the heme is to a cation-cation complex in the case of D. acetoxidans, but for G. sulfurreducens, it is to a single uranyl cation, which then forms a U(V)-U(VI) complex with a second uranyl cation. For both enzymes, the subsequent catalytic pathways are very similar. A U(V)-U(V) complex is formed, which then undergoes disproportionation via two successive protonation steps of one uranyl group, to give a U(VI)-U(IV) complex which dissociates to individual U(VI) and U(IV) species, the former being bound at the enzyme active site. Intermediate structures along the catalytic pathway are consistent with EXAFS data. © 2008 American Chemical Society.
    Original languageEnglish
    Pages (from-to)4451-4457
    Number of pages6
    JournalJournal of Physical Chemistry A
    Volume112
    Issue number19
    DOIs
    Publication statusPublished - 15 May 2008

    Keywords

    • EFFECTIVE CORE POTENTIALS
    • AUTOMATED DOCKING
    • ELECTRON-TRANSFER
    • AQUO
    • COMPLEXES
    • FREE-ENERGY
    • CHEMISTRY
    • URANIUM
    • COORDINATION
    • ION
    • CARBONATE

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