Reversal and Amplification of the Enantioselectivity of Biocatalytic Desymmetrization toward Meso Heterocyclic Dicarboxamides Enabled by Rational Engineering of Amidase

By
rational engineering of amidase, the efficient biocatalytic
desymmetrization of meso O-heterocyclic dicarboxamides
for synthesizing both antipodes of functionalized cyclic motifs was
presented. Based on the enzyme-substrate binding model suggested by
molecular docking, a rational mutagenesis strategy was established.
The reversal and amplification of enantioselectivity of amidase were
achieved by generating and testing only 10 variants. This enabled
the quick access of both antipodes of products in very good yields
and up to 99.5% ee under mild conditions. The engineered biocatalyst
exhibits a wide substrate promiscuity and can expand to both N-heterocyclic and carbocyclic dicarboxamides with the retained
high efficiency and excellent enantioselectivity. The desymmetrization
mechanism for amidase, including the wild-type and the variant, was
revealed by molecular dynamics simulations and quantum mechanical/molecular
mechanical modeling. It suggests a delicate cooperation between the
activation and binding sites by nesting the cyclic skeleton of the
substrates.