Thierry Tron

Affiliation
Institut des Sciences Moléculaires de Marseille
CNRS, Aix Marseille Université
Service 342, Faculté des Sciences de Saint-Jérôme
Marseille

Web:

Research interests: metal-containing oxidases, laccases, biocatalysis, photocatalysis

Abstract:

Title: New bio-catalysts based on functionnalized laccases

Ludovic Schneider, Yasmina Mekmouche, Pierre Rousselot-Pailley, A. Jalila Simaan, Viviane Robert, Marius Réglier, Thierry Tron

Aix-Marseille Université, iSm2/BiosCiences UMR CNRS 7313, case 342, Faculté des Sciences et Techniques, Pôle de l’Etoile, 13397 Marseille cedex 20, France

Laccases are very well known biocatalysts with great robustness, high oxidation power and substrate versatility (among other properties).[1] They contain a unique set of copper ions made of one each of the three types of biorelevant copper sites: type 1 (T1), type 2 (T2) and a binuclear type 3 (T3), and couple dioxygen reduction to the oxidation of substrates, either organic or metal ion.[2] They belong to the Blue Copper Binding Domain (BCBD) family of proteins in which the archetypal members are the plant or bacterial electron transfer protein cupredoxins (CUP). In this family, function is modulated by the number of CUP domains, the number and type copper atoms and the fusion to non metalled domains. Taking natural plasticity within the BCBD family as a source of inspiration for the engineering of laccases,[3, 4] we shape new catalysts based on a laccase functionnalized with different “plug-ins”.

One of our targets is a robust system where light absorption triggers electron transfer from a catalytic centre to a renewable electron acceptor. We have recently reported the light driven four-electron reduction of dioxygen to water via a laccase using either a [Ru(bpy)3]2+ or a [ZnTMPyP]4+ type chromophores and EDTA as sacrificial electron donor.[5] We present here the first example of photooxygenation of styrene with a system driven by an enzyme using dioxygen as a final and renewable electron acceptor. Substrate oxygenation occurs upon irradiation of the aerated enzyme solution containing a [Ru(bpy)3]2+ complex acting both as sensitizer and likely as a precursor of the catalytic species. Styrene oxygenation is dependent on the enzyme, dioxygen and light and is neither consecutive to a reaction with H2O2 nor with photo-generated O2 reactive species. The concomitant dioxygen reduction is dependent on styrene and light. Substantial amounts of styrene oxygenation products are obtained with this enzyme/sensitizer hybrid system thereby supporting its suitability for photo-driven transformations of substrates. Such a molecular photo-oxygenation catalyst using O2 as renewable electron acceptor allows avoiding the need of traditional systems for both a sacrificial electron acceptor and an overpressure of an inert gas.

[1] T. Tron, in Encyclopedia of Metalloproteins, Kret.singer, RH, Uversky, VN, Permyakov, EA. (Eds.) Springer, New York, 2013, pp. 1066-1070.

[2] E. Solomon, U. Sundaram, T. Machonkin, Chem. Rev., 199696, 2563-2605.

[3] V. Balland, C. Hureau, A. Cusano, Y. Liu, T. Tron, B, Limoges, Chem. Eu. J., 200814, 7186-92.

[4] V. Robert, Y. Mekmouche, P. Rousselot Pailley, T. Tron, Curr. Genomics, 201112, 123-129.

[5] a) A. Simaan, Y. Mekmouche, C. Herrero, P. Moreno, A. Aukauloo, J. Delaire, M. Réglier, T. Tron. Chem. Eu. J., 2011, 17, 11743-11746; b) T. Lazarides, I. V. Sazanovich, A. J. Simaan, M. C. Kafentzi, M. Delor, Y. Mekmouche, B. Faure, M. Réglier, J. A. Weinstein, A. G. Coutsolelos, T. Tron, J. Am. Chem. Soc. 2013135, 3095-3103.