An Engineered Aminotransferase for the Synthesis of a Key Chiral Intermediate of Lenacapavir

We report the development of an engineered aminotransferase for the synthesis of a key chiral intermediate of the anti-HIV drug Lenacapavir. Due to the sterically demanding nature of the ketone substrate, a substrate walking approach was adopted during directed evolution to unlock desired aminotransferase activity starting from a parent template (TA25) with no observable activity for the target reaction. Introduction of 6 mutations into TA25 over 4 rounds of directed evolution led to the development of an engineered aminotransferase that affords the target chiral amine product with 90% conversion and >99% e.e. in favor of the desired S-enantiomer. The enzyme serves as a valuable template for the development of an industrial biocatalyst for the manufacture of Lenacapavir