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Crystal Structures and Catalytic Mechanism of l ‐ erythro ‐3,5‐Diaminohexanoate Dehydrogenase and Rational Engineering for Asymmetric Synthesis of β‐Amino Acids
Author(s) -
Liu Na,
Wu Lian,
Feng Jinhui,
Sheng Xiang,
Li Jian,
Chen Xi,
Li Jianjiong,
Liu Weidong,
Zhou Jiahai,
Wu Qiaqing,
Zhu Dunming
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202017225
Subject(s) - amino acid , diastereomer , chemistry , rational design , stereochemistry , mutagenesis , protein engineering , enzyme , biochemistry , nanotechnology , mutation , materials science , gene
Amino acid dehydrogenases (AADHs) have shown considerable potential as biocatalysts in the asymmetric synthesis of chiral amino acids. However, compared to the widely studied α‐AADHs, limited knowledge is available about β‐AADHs that enable the synthesis of β‐amino acids. Herein, we report the crystal structures of a l ‐ erythro ‐3,5‐diaminohexanoate dehydrogenase and its variants, the only known member of β‐AADH family. Crystal structure analysis, site‐directed mutagenesis studies and quantum chemical calculations revealed the differences in the substrate binding and catalytic mechanism from α‐AADHs. A number of rationally engineered variants were then obtained with improved activity (by 110–800 times) toward various aliphatic β‐amino acids without an enantioselectivity trade‐off. Two β‐amino acids were prepared by using the outstanding variants with excellent enantioselectivity (>99 % ee ) and high isolated yields (86–87 %). These results provide important insights into the molecular mechanism of 3,5‐DAHDH, and establish a solid foundation for further design of β‐AADHs for the asymmetric synthesis of β‐amino acids.