MauG, a diheme enzyme that catalyzes tryptophan tryptophylquinone biosynthesis by remote catalysis

    Authors

    S. Shin;V. L. Davidson

    Comments

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    Abbreviated Journal Title

    Arch. Biochem. Biophys.

    Keywords

    Electron transfer; Posttranslational modification; Protein radical; Peroxidase; Oxygenase; High-valence iron; ELECTRON-TRANSFER REACTIONS; C-TYPE CYTOCHROMES; METHYLAMINE; DEHYDROGENASE; PARACOCCUS-DENITRIFICANS; DIFFERENT FORMS; SPIN HEME; PROTEIN; MECHANISM; COFACTOR; COMPLEX; Biochemistry & Molecular Biology; Biophysics

    Abstract

    MauG contains two c-type hemes with atypical physical and catalytic properties. While most c-type cytochromes function simply as electron transfer mediators, MauG catalyzes the completion of tryptophan tryptophylquinone (TFQ)(1) biosynthesis within a precursor protein of methylamine dehydrogenase. This posttranslational modification is a six-electron oxidation that requires crosslinking of two Trp residues, oxygenation of a Trp residue and oxidation of the resulting quinol to ITQ. These reactions proceed via a bis-Fe-IV state in which one heme is present as Fe-IV=O and the other is Fe-IV with axial heme ligands provided by His and Tyr side chains. Catalysis does not involve direct contact between the protein substrate and either heme of MauG. Instead it is accomplished by remote catalysis using a hole hopping mechanism of electron transfer in which Trp residues of MauG are reversibly oxidized. In this process, long range electron transfer is coupled to the radical mediated chemical reactions that are required for TTQ biosynthesis. (C) 2013 Elsevier Inc. All rights reserved.

    Journal Title

    Archives of Biochemistry and Biophysics

    Volume

    544

    Publication Date

    1-1-2014

    Document Type

    Review

    Language

    English

    First Page

    112

    Last Page

    118

    WOS Identifier

    WOS:000332141200012

    ISSN

    0003-9861

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