Light-driven decarboxylative deuteration enabled by a divergently engineered photodecarboxylase

Qi Wu,Jiajie Fan,Danyang Li,Zhiguo Wang,Haonan Zhou,Jian Xu,Weihua Xu,Xianfu Lin,Yujiao Lou

doi:10.1038/s41467-021-24259-6

Abstract

Despite the well-established chemical processes for C-D bond formation, the toolbox of enzymatic methodologies for deuterium incorporation has remained underdeveloped. Here we describe a photodecarboxylase from Chlorella variabilis NC64A (CvFAP)-catalyzed approach for the decarboxylative deuteration of various carboxylic acids by employing D2O as a cheap and readily available deuterium source. Divergent protein engineering of WT-CvFAP is implemented using Focused Rational Iterative Site-specific Mutagenesis (FRISM) as a strategy for expanding the substrate scope. Using specific mutants, several series of substrates including different chain length acids, racemic substrates as well as bulky cyclic acids are successfully converted into the deuterated products (>40 examples). In many cases WT-CvFAP fails completely. This approach also enables the enantiocomplementary kinetic resolution of racemic acids to afford chiral deuterated products, which can hardly be accomplished by existing methods. MD simulations explain the results of improved catalytic activity and stereoselectivity of WT CvFAP and mutants.

Highlights

Despite the well-established chemical processes for C-D bond formation, the toolbox of enzymatic methodologies for deuterium incorporation has remained underdeveloped
Most of these approaches rely on transition metal complexes or harsh reaction conditions, which may suffer from high costs and raise environmental issues
We commenced our study by evaluating the viability for the decarboxylation deuterium incorporation with palmitic acid (1A, Table 1) as starting material because it is naturally occurring and has the highest decarboxylation activity under the catalysis of WT-CvFAP49,50

Summary

Introduction

Despite the well-established chemical processes for C-D bond formation, the toolbox of enzymatic methodologies for deuterium incorporation has remained underdeveloped. In contrast to traditional chemical photoredox deuteration, we discovered that this bio-radical transformation can be run in a manner open to air and without the requirement of extra thiol as a hydrogen atom transfer (HAT) additive (Table 1, entry 8)[13] Lastly, the influence of the various cosolvent addition, substrate concentration and reaction time were further studied and the best result of WT CvFAP-catalyzed decarboxylation deuterium of palmitic acid was obtained from the reaction with 100 mM substrate concentration and 20% vol DMSO as cosolvent after 12 h

Results

Conclusion