Boosting photobioredox catalysis by morpholine electron donors under aerobic conditions

Leticia C.P. Goncąlves, Hamid R. Mansouri, Shadi Pourmehdi, Mohamed Abdellah, Bruna S. Fadiga, Erick L. Bastos, Jacinto Sá, Marko D. Mihovilovic, Florian Rudroff

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

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 α,β-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.

Original languageEnglish
Pages (from-to)2682-2688
Number of pages7
JournalCatalysis Science and Technology
Volume9
Issue number10
DOIs
Publication statusPublished - 2019
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis

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