Assessment of Enzyme Functionality at Metal-Organic Framework Interfaces Developed through Molecular Simulations

The catalytic efficiency and unrivaled selectivity with which enzymes convert substrates to products have been tapped for widespread chemical transformations within biomedical technology, biofuel production, gas sensing, and the upgrading of commodity chemicals, just to name a few. However, the feasibility of enzymes implementation is challenged by the lack of reusability and loss of native catalytic activity due to the irreversible biocatalyst denaturation at high temperatures and in the presence of industrial solvents. Enzyme immobilization, a prerequisite for enzyme reusability, offers controllable strategies for increased functional viability of the biocatalyst in a synthetic environment. Herein we used molecular dynamics (MD) simulations and probed the noncovalent interactions between model enzymes of technological interest, i.e., carbonic anhydrase (CA) and myeloperoxidase (MPO), with selected metal-organic frameworks (MOFs; MIL-160 and ZIF-8) of proven industrial implementation. We found that the CA and MPO can bind to MIL-160 at optimal binding energies of 201 and 501 kJ mol^-1, respectively, that are strongly influenced by the increased incidence of hydrogen bonding between enzymes and the frameworks. The free energy of binding of enzymes to ZIF-8, on the other hand, was found to be less strongly influenced by hydrogen bonding networks relative to the occurrence of hydrophobic-hydrophobic interactions that yielded 106 kJ mol^-1 for CA and 201 kJ mol^-1 for MPO.