Testing the acceleration of the flavin-N(5)-hydroperoxide formation by O2 binding in monooxygenase EncM by QM/MM MD simulations

In monooxygenase EncM, the reduced flavin cofactor binds O2 to form an uncommon oxygenating species – flavin-N(5)-oxide. Here we present the results of QM/MM MD demonstrating that the regioselective O2 activation is driven by the O2 binding pose in EncM. We report the free-energy of the superoxide radical binding to the flavin N(5) and C(4a) positions and link these energies and distances of O2 binding returned by the QM/MM MD simulations.