Fig. 3

QM/MM calculation of AcCO. A Proposed catalytic reactions of AcCO. The proton and hydride (H⁻) transfer from CHDM and HMCA to H466 (N^ε2) and FAD N(5) is marked as arrows. B Relative energy profile (in kcal·mol⁻¹) of hydride (H⁻) transfer from CHDM and HMCA, along with schematic drawings of key intermediates involved in the reaction. The WT is shown in black line, variant W4 is shown in red line