Engineering a Formate Dehydrogenase for NADPH Regeneration

This work demonstrated the generative process of a molecularly evolved formate dehydrogenase from Candida dubliniensis (CdFDH). By structure-based semi-rational design, a combinatorial mutant M4 showed dramatically enhanced reactivity toward NADP⁺. Then CdFDH-M4 was successfully applied to several representative NADPH-needed bio-transformations, with perfect total turnover numbers (ranging from 135 to 986) of cofactor with respect to NADP⁺ reduction.

Abstract

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.

Zum Volltext