Open AccessEngineering a d-lactate dehydrogenase that can super-efficiently utilize NADPH and NADH as cofactors
Author(s) -
Hengkai Meng,
Li Pi,
Haijie Sun,
Zhen Cai,
Jie Zhou,
Jianping Lin,
Yin Li
Publication year - 2016
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/srep24887
Subject(s) - cofactor , lactate dehydrogenase , l lactate dehydrogenase , biochemistry , nad+ kinase , dehydrogenase , chemistry , computer science , enzyme
Engineering the cofactor specificity of a natural enzyme often results in a significant decrease in its activity on original cofactor. Here we report that a NADH-dependent dehydrogenase ( d -LDH) from Lactobacillus delbrueckii 11842 can be rationally engineered to efficiently use both NADH and NADPH as cofactors. Point mutations on three amino acids (D176S, I177R, F178T) predicted by computational analysis resulted in a modified enzyme designated as d -LDH*. The K cat /K m of the purified d -LDH* on NADPH increased approximately 184-fold while the K cat /K m on NADH also significantly increased, showing for the first time that a rationally engineered d -LDH could exhibit comparable activity on both NADPH and NADH. Further kinetic analysis revealed that the enhanced affinity with NADH or NADPH and the significant increased K cat of d -LDH* resulted in the significant increase of d -LDH* activity on both NADPH and NADH. This study thus demonstrated that the cofactor specificity of dehydrogenase can be broadened by using targeted engineering approach, and the engineered enzyme can efficiently function in NADH-rich, or NADPH-rich, or NADH and NADPH-rich environment.