Engineering of Yeast Old Yellow Enzyme OYE3 Enables Its Capability Discriminating of (E)-Citral and (Z)-Citral.

Tairan Wang,Chenze Lu,Ran Wei,Duxia Yang,Xiangxian Ying,Xia Li,Mengge Han,Yunpeng Jia,Lijun Jin,Yingting Feng,Zuonan Liang

doi:10.3390/molecules26165040

Tairan Wang, Chenze Lu + Show 9 more

Open Access

https://doi.org/10.3390/molecules26165040

Copy DOI

Abstract

The importance of yeast old yellow enzymes is increasingly recognized for direct asymmetric reduction of (E/Z)-citral to (R)-citronellal. As one of the most performing old yellow enzymes, the enzyme OYE3 from Saccharomyces cerevisiae S288C exhibited complementary enantioselectivity for the reduction of (E)-citral and (Z)-citral, resulting in lower e.e. value of (R)-citronellal in the reduction of (E/Z)-citral. To develop a novel approach for the direct synthesis of enantio-pure (R)-citronellal from the reduction of (E/Z)-citral, the enzyme OYE3 was firstly modified by semi-rational design to improve its (R)-enantioselectivity. The OYE3 variants W116A and S296F showed strict (R)-enantioselectivity in the reduction of (E)-citral, and significantly reversed the (S)-enantioselectivity in the reduction of (Z)-citral. Next, the double substitution of OYE3 led to the unique variant S296F/W116G, which exhibited strict (R)-enantioselectivity in the reduction of (E)-citral and (E/Z)-citral, but was not active on (Z)-citral. Relying on its capability discriminating (E)-citral and (Z)-citral, a new cascade reaction catalyzed by the OYE3 variant S296F/W116G and glucose dehydrogenase was developed, providing the enantio-pure (R)-citronellal and the retained (Z)-citral after complete reduction of (E)-citral.

Highlights

Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, These authors contributed to this work
The BASF method is simpler, in which (E/Z)-citral is distilled to obtain high-purity (E)-citral and (R)-citronellal is synthesized through asymmetric hydrogenation of (E)-citral [7,8]
The enzyme OYE3 had the opposite enantioselectivity in the asymmetric reduction of (E)-citral and (Z)-citral, whose corresponding e.e. values were 63.45% (R) and 47.22%

Summary

Introduction

Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, These authors contributed to this work. The importance of yeast old yellow enzymes is increasingly recognized for direct asymmetric reduction of (E/Z)-citral to (R)-citronellal. As one of the most performing old yellow enzymes, the enzyme OYE3 from Saccharomyces cerevisiae S288C exhibited complementary enantioselectivity for the reduction of (E)-citral and (Z)-citral, resulting in lower e.e. value of (R)-citronellal in the reduction of (E/Z)-citral. To develop a novel approach for the direct synthesis of enantio-pure (R)citronellal from the reduction of (E/Z)-citral, the enzyme OYE3 was firstly modified by semi-rational design to improve its (R)-enantioselectivity. Relying on its capability discriminating (E)-citral and (Z)-citral, a new cascade reaction catalyzed by the OYE3 variant S296F/W116G and glucose dehydrogenase was developed, providing the enantio-pure (R)-citronellal and the retained (Z)-citral after complete reduction of (E)-citral. The industrial production of (R)citronellal is currently synthesized through chemical approaches starting from myrcene (Takasago company in Japan) or citral (BASF company in Germany). Biocatalysis is currently recognized as a promising alternative, considering the demands of modern organic synthesis [9,10]

Methods

Results

Conclusion