Boosting photobioredox catalysis by morpholine electron donors under aerobic conditions

Author(s)

Goncalves, Leticia C. P. ^[1] ; Mansouri, Hamid R. ^[1] ; PourMehdi, Shads ^[1] ; Abdellah, Mohamed ^{[2, 3]} ; Fadiga, Bruna S. ^{[4, 2]} ; Bastos, Erick L. ^[4] ; Sa, Jacinto ^{[2, 5]} ; Mihovilovic, Marko D. ^[1] ; Rudroffe, Florian ^[1]

Affiliation

^[1] TU Wien, Inst Appl Synthet Chem, Getreidemarkt 9 163, A-1060 Vienna - Austria

^[2] Uppsala Univ, Angstrom Lab, Dept Chem, Phys Chem Div, S-75120 Uppsala - Sweden

^[3] South Valley Univ, Qena Fac Sci, Dept Chem, Qena 83523 - Egypt

^[4] Univ Sao Paulo, Inst Chem, Dept Fundamental Chem, BR-03178200 Sao Paulo - Brazil

^[5] Polish Acad Sci, Inst Phys Chem, PL-01224 Warsaw - Poland

• Document type: Journal article
• Source: CATALYSIS SCIENCE & TECHNOLOGY; v. 9, n. 10, p. 2682-2688, MAY 21 2019.
• Web of Science Citations: 2

Abstract

Light-driven reduction of flavins, e.g. FAD or FMN, by sacrificial electron donors emerged as a convenient method to promote biocatalytic transformations. However, flavin activation has been restricted to oxygen-free conditions to prevent enzyme deactivation caused by reactive oxygen species (ROS). Herein, we show that the photoreduction of FMN by morpholines, including 3-(N-morpholino)propanesulfonic acid (MOPS), lessens the deactivation of the enoate reductase XenB from Pseudomonas sp. during the stereoselective asymmetric enzymatic reduction of a model ,-unsaturated diketone under aerobic conditions, leading to a 91% GC-yield and a stereoselectivity greater than 94%. The kinetic stability of the thermolabile XenB was increased by more than 20-fold in MOPS buffer compared to that in Tris-HCl buffer, and a pronounced positive effect on the transition midpoint temperature was observed. The reactive form of the FMN photocatalyst is stabilized by the formation of a (3){[}FMN--MOPS+] ensemble, which reduces the formation of hydrogen peroxide and other ROS in the presence of oxygen. These results contribute to broaden the application of photobiocatalytic transformations using flavin-dependent reductases. (AU)

• FAPESP's process: 17/50130-9 - Bioinspired photoactive electron donors
• Grantee: Erick Leite Bastos
• Support Opportunities: Regular Research Grants