Oxygen activation by mononuclear nonheme iron dioxygenases involved in the degradation of aromatics

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DOI: 10.1007/s00775-017-1436-5

Cite this article as:
Wang, Y., Li, J. & Liu, A. J Biol Inorg Chem (2017) 22: 395. doi:10.1007/s00775-017-1436-5
Part of the following topical collections:
  1. 60 Years of Oxygen Activation

Abstract

Molecular oxygen is utilized in numerous metabolic pathways fundamental for life. Mononuclear nonheme iron-dependent oxygenase enzymes are well known for their involvement in some of these pathways, activating O2 so that oxygen atoms can be incorporated into their primary substrates. These reactions often initiate pathways that allow organisms to use stable organic molecules as sources of carbon and energy for growth. From the myriad of reactions in which these enzymes are involved, this perspective recounts the general mechanisms of aromatic dihydroxylation and oxidative ring cleavage, both of which are ubiquitous chemical reactions found in life-sustaining processes. The organic substrate provides all four electrons required for oxygen activation and insertion in the reactions mediated by extradiol and intradiol ring-cleaving catechol dioxygenases. In contrast, two of the electrons are provided by NADH in the cis-dihydroxylation mechanism of Rieske dioxygenases. The catalytic nonheme Fe center, with the aid of active site residues, facilitates these electron transfers to O2 as key elements of the activation processes. This review discusses some general questions for the catalytic strategies of oxygen activation and insertion into aromatic compounds employed by mononuclear nonheme iron-dependent dioxygenases. These include: (1) how oxygen is activated, (2) whether there are common intermediates before oxygen transfer to the aromatic substrate, and (3) are these key intermediates unique to mononuclear nonheme iron dioxygenases?

Graphical Abstract

Keywords

Catalytic strategies Crystal structure High-valent iron species Metabolism Nonheme iron enzymes Oxidative degradation Reactive oxygen species Ring-cleaving dioxygenase Spectroscopy 

Funding information

Funder NameGrant NumberFunding Note
Division of Molecular and Cellular Biosciences
  • MCB-0843537
National Institute of Mental Health
  • MH107985
Division of Chemistry
  • CHE-1623856
National Institute of General Medical Sciences
  • GM107529, GM108988

Copyright information

© SBIC 2017

Authors and Affiliations

  1. 1.Department of ChemistryUniversity of Texas at San AntonioSan AntonioUSA

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