Engineering a Formate Dehydrogenase for NADPH Regeneration

Nicotinamide adenine dinucleotide (NADH) and nicotinamide adenine dinucleotide phosphate (NADPH) constitute major hydrogen donors for oxidative/reductive bio-transformations. NAD(P)H regeneration systems coupled with formate dehydrogenases (FDHs) represent a dreamful method. However, most of the native FDHs are NAD(+)-dependent and suffer from insufficient reactivity compared to other enzymatic tools, such as glucose dehydrogenase. An efficient and competitive NADP(+)-utilizing FDH necessitates the availability and robustness of NADPH regeneration systems. Herein, we report the engineering of a new FDH from Candida dubliniensis (CdFDH), which showed no strict NAD(+) preference by a structure-guided rational/semi-rational design. A combinatorial mutant CdFDH-M4 (D197Q/Y198R/Q199N/A372S/K371T/Q375/K167R/H16L/K159R) exhibited 75-fold intensification of catalytic efficiency (k(cat)/K-m). Moreover, CdFDH-M4 has been successfully employed in diverse asymmetric oxidative/reductive processes with cofactor total turnover numbers (TTNs) ranging from 135 to 986, making it potentially useful for NADPH-required biocatalytic transformations.

Automated summary

NADH and NADPH are major hydrogen donors for biochemical transformations. NAD(P)H regeneration systems coupled with formate dehydrogenase (FDH) are ideal methods. In this study, a new engineered FDH from Candida dubliniensis (CdFDH) was developed, which showed significantly improved catalytic efficiency and can be used for various NADPH-required biocatalytic transformations.