Deracemization and Stereoinversion to Aromatic d‑Amino Acid Derivatives with Ancestral l‑Amino Acid Oxidase

• Published in: ACS catalysis Vol. 9; no. 11; pp. 10152 - 10158
• Main Authors: Nakano, Shogo, Minamino, Yuki, Hasebe, Fumihito, Ito, Sohei
• Format: Journal Article
• Language: English
• Published: American Chemical Society 01.11.2019
• Subjects: deracemization; artificial protein; ancestral sequence reconstruction; l-amino acid oxidase; d-amino acid derivatives
• ISSN: 2155-5435; 2155-5435
• DOI: 10.1021/acscatal.9b03418

Enantiomerically pure amino acid derivatives could be foundational compounds for peptide drugs. Deracemization of racemates to l-amino acid derivatives can be achieved through the reaction of evolved d-amino acid oxidase and chemical reductants, whereas deracemization to d-amino acid derivatives has not progressed due to the difficulty associated with the heterologous expression of l-amino acid oxidase (LAAO). In this study, we succeeded in developing an ancestral LAAO (AncLAAO) bearing broad substrate selectivity (13 l-amino acids) and high productivity through an Escherichia coli expression system (∼50.7 mg/L). AncLAAO can be applied to perform deracemization to d-amino acids in a similar way to deracemization to l-amino acids. In fact, full conversion (>99% ee, d-form) could be achieved for 16 racemates, including nine d,l-Phe derivatives, six d,l-Trp derivatives, and a d,l-phenylglycine. Taken together, we believe that AncLAAO could be a key enzyme to obtain optically pure d-amino acid derivatives in the future.