Title

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

Authors

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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