Covalent Insertion of a Mn(Salen) Type Complex in Cross‐Linked Protein Crystals: Design of an Enantioselective Artificial Epoxidase

Artificial enzymes represent a promising alternative for performing non-natural reactions in biocatalysis. Here, we illustrate the potential of cross-linked enzyme crystals (CLEC) to achieve enantioselective epoxidation through the generation of an artificial enzyme obtained by direct covalent anchoring of a manganese complex as an artificial active site within a protein. Enantiomeric excess (ee) of up to 90% on cis-β-methylstyrene was measured when the covalent binding yield was maximized, thanks to the remarkable behavior of the crystals. The structure of the modified enzyme, NikA, is provided. This work adds to the growing body of examples highlighting the advantages of CLEC in oxidation catalysis.