Title

Posttranslational Biosynthesis of the Protein-Derived Cofactor Tryptophan Tryptophylquinone

Authors

Authors

V. L. Davidson;C. M. Wilmot

Comments

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Abbreviated Journal Title

Annu. Rev. Biochem..

Keywords

electron transfer; heme; enzyme; high-valent iron; hole hopping; QUINOHEMOPROTEIN AMINE DEHYDROGENASE; ELECTRON-TRANSFER COMPLEX; MAU; GENE-CLUSTER; METHYLAMINE DEHYDROGENASE; PARACOCCUS-DENITRIFICANS; CRYSTAL-STRUCTURE; QUINONE COFACTOR; LYSYL OXIDASE; DIFFERENT FORMS; REDOX COFACTOR; Biochemistry & Molecular Biology

Abstract

Methylamine dehydrogenase (MADH) catalyzes the oxidative deamination of methylamine to formaldehyde and ammonia. Tryptophan tryptophylquinone (TTQ) is the protein-derived cofactor of MADH required for this catalytic activity. TTQ is biosynthesized through the posttranslational modification of two tryptophan residues within MADH, during which the indole rings of two tryptophan side chains are cross-linked and two oxygen atoms are inserted into one of the indole rings. MauG is a c-type diheme enzyme that catalyzes the final three reactions in TTQ formation. In total, this is a six-electron oxidation process requiring three cycles of MauG-dependent two-electron oxidation events using either H2O2 or O-2. The MauG redox form responsible for the catalytic activity is an unprecedented bis-Fe-IV species. The amino acids of MADH that are modified are similar to 40 angstrom from the site where MauG binds oxygen, and the reaction proceeds by a hole hopping electron transfer mechanism. This review addresses these highly unusual aspects of the long-range catalytic reaction mediated by MauG.

Journal Title

Annual Review of Biochemistry, Vol 82

Volume

82

Publication Date

1-1-2013

Document Type

Review; Book Chapter

Language

English

First Page

531

Last Page

550

WOS Identifier

WOS:000321698100019

ISSN

0066-4154

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