Physical Chemistry

Luboš Rulíšek

Reaction mechanisms of many non-heme diiron enzymes (such as Δ9 desaturase, Δ9D) represent an  unresolved problem with a potentially enormous impact in the whole field of C-H activation by metalloenzymes and smaller mono- and diiron catalysts. The key issue in an elucidation of the particular reaction mechanism is characterization and understanding of the rate-determining step (RDS) as well as structures of reactive intermediates, such as Fe(IV)=O, Fe(III)-OOH (or bridged  Fe(IV)-O-Fe(IV), Fe(III)-O-Fe(IV)) units. The mechanistic view of the particular reaction pathway may explain a observed variety in the reactions catalyzed by the non-heme diiron enzymes (such as desaturation vs. hydroxylation reaction channels in Δ9D). Cutting-edge computational methods and techniques (including the emerging density-matrix renormalization group multireference calculations, DMRG-CASPT2) in combination with the hybrid quantum mechanical and molecular mechanical (QM/MM) calculations will be used to achieve this goal.