Lytic Polysaccharide Monooxygenases ScLPMO10B and ScLPMO10C Are Stable in Ionic Liquids As Determined by Molecular Simulations

Lytic polysaccharide monooxygenases (LPMOs) are a newly discovered family of enzymes proposed to work synergistically with cellulases and aid in the decomposition of cellulose for the creation of environmentally friendly fuels and chemicals. To our knowledge, evaluation of the stability of LPMOs in ionic liquid (IL) solvents at relevant biomass processing conditions has not been explored. Herein, molecular dynamics simulations of ScLPMO10B and ScLPMO10C in three ILs at 10 and 20 wt% in water and in pure water have been performed. Enzyme stability was predicted to be high on the basis of structural and dynamic analyses we performed. We used the simulations to identify key areas that deviate from the crystal structures as a starting place for surface charge modifications to increase stability in ILs. Results show that, in general, both enzymes have a high degree of stability across the range of IL solutions tested. For each enzyme, two regions were identified that showed notable deviations from the crystal structure. In addition to providing a basis for future rational design efforts, this work represents a first step toward engineering LPMOs to function efficiently in enzyme cocktails for use in industrial biomass processing applications with ILs.