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Benzoyl-CoA Epoxidase of Azoarcus evansii

  1. Tobias Weinert2,
  2. Liv J Rather-Adler1,
  3. Eckhard Bill3,
  4. Georg Fuchs1,
  5. Ulrich Ermler2

Published Online: 23 SEP 2013

DOI: 10.1002/9781119951438.eibc2170

Encyclopedia of Inorganic and Bioinorganic Chemistry

Encyclopedia of Inorganic and Bioinorganic Chemistry

How to Cite

Weinert, T., Rather-Adler, L. J., Bill, E., Fuchs, G. and Ermler, U. 2013. Benzoyl-CoA Epoxidase of Azoarcus evansii. Encyclopedia of Inorganic and Bioinorganic Chemistry. 1–13.

Author Information

  1. 1

    Universität Freiburg, Freiburg, Germany

  2. 2

    Max-Planck-Institut für Biophysik, Frankfurt am Main, Germany

  3. 3

    Max-Planck-Institut für Bioanorganische Chemie, Mülheim an der Ruhr, Germany

Publication History

  1. Published Online: 23 SEP 2013

Abstract

Mineralization of aromatic compounds—present in large amounts in the biosphere—is a challenging chemical process. Nature developed several sophisticated degradation strategies, one of them being the benzoate-degrading CoA-linked Box pathway that is present in 5% of all sequenced bacterial genomes. The central dearomatization and cleavage reaction is accomplished by the BoxABC multicomponent system; BoxA is a reductase, BoxB an epoxidase using a single O2 molecule, and BoxC a stimulator for the BoxB reaction and a hydrolase for subsequent ring cleavage. BoxB is a member of the important diiron carboxylate protein family characterized by a catalytic diiron center embedded in a central four-helix bundle. Benzoyl-CoA is located inside a 20 Å long channel of BoxB. The position of its phenyl ring relative to the diiron center is accurately defined in the X-ray structure and allowed valuable insight into O2 binding and activation, epoxidation, and the stereoselectivity of the reaction. Kinetic- and electron paramagnetic resonance (EPR)-spectroscopic investigations provided information about the reaction dynamics and reaction intermediates. On the basis of the total data available, a detailed enzymatic mechanism is proposed.

3D Structure

  • original image

    Ribbon diagram of BoxB of A. evansii. The four-helix bundle carrying the diiron center is drawn blue, conserved helices in green, and the variable residual parts in gray. PDB code: 3PER, 3PF7, 3Q16, 3PM5. This and the other structural figures were produced with program PyMOL (Schrödinger, LLC, http://www.schrodinger.com).

Keywords:

  • benzoate degradation;
  • CoA ;
  • Azoarcus evansii ;
  • oxygen activation;
  • BoxB ;
  • dearomatization;
  • epoxidation