Tracking light-induced electron transfer toward O2 in a hybrid photoredox-laccase system

Rajaa Farran; Yasmina Mekmouche; Nhat Tam Vo; Christian Herrero; Annamaria Quaranta; Marie Sircoglou; Frédéric Banse; Pierre Rousselot-Pailley; A Jalila Simaan; Ally Aukauloo; Thierry Tron; Winfried Leibl

doi:10.1016/j.isci.2021.102378

Tracking light-induced electron transfer toward O₂ in a hybrid photoredox-laccase system

iScience. 2021 Mar 31;24(4):102378. doi: 10.1016/j.isci.2021.102378. eCollection 2021 Apr 23.

Authors

Affiliations

¹ Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91191 Gif-sur-Yvette, France.
² Lebanese International University, 146404 Mazraa, Beirut, Lebanon.
³ Aix Marseille Université, Centrale Marseille, CNRS, iSm2 UMR 7313, 13397 Marseille, France.
⁴ Université Paris-Saclay, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), 91405 Orsay, France.

Abstract

Photobiocatalysis uses light to perform specific chemical transformations in a selective and efficient way. The intention is to couple a photoredox cycle with an enzyme performing multielectronic catalytic activities. Laccase, a robust multicopper oxidase, can be envisioned to use dioxygen as a clean electron sink when coupled to an oxidation photocatalyst. Here, we provide a detailed study of the coupling of a [Ru(bpy)₃]²⁺ photosensitizer to laccase. We demonstrate that efficient laccase reduction requires an electron relay like methyl viologen. In the presence of dioxygen, electrons transiently stored in superoxide ions are scavenged by laccase to form water instead of H₂O₂. The net result is the photo accumulation of highly oxidizing [Ru(bpy)₃]³⁺. This study provides ground for the use of laccase in tandem with a light-driven oxidative process and O₂ as one-electron transfer relay and as four-electron substrate to be a sustainable final electron acceptor in a photocatalytic process.

Keywords: Biomolecules; Catalysis; Chemistry.