Effect of Oil Polarity on the Protein Adsorption at Oil-Water Interfaces

Protein adsorption at oil-water interfaces hasreceivedmuch attention in applications of food emulsion and biocatalysis.The protein activity is influenced by the protein orientation andconformation. The oil polarity is expected to influence the orientationand conformation of adsorbed proteins by modulating intermolecularinteractions. Hence, it is possible to tune the protein emulsion stabilityand activity by varying the oil polarity. Martini v3.0-based coarse-grainedmolecular dynamics (CGMD) simulations were employed to investigatethe effect of oil polarity on the orientation and conformation ofhydrophobin (HFBI) and Candida antarctica lipase B (CALB) adsorbed at triolein-water, hexadecane-water,and octanol-water interfaces for the first time. The proteinadsorption orientation was predicted through the hydrophobic dipole,indicating that protein adsorption exists in preferred orientationsat hydrophobic oil interfaces. The conformation of the adsorbed HFBIis well conserved, whereas relatively larger conformational changesoccur during the CALB adsorption as the oil hydrophobicity increases.Comparisons on the adsorption interaction energy of proteins withoils confirm the relationship between the oil polarity and the interactionstrength of proteins with oils. In addition, CGMD simulations allowlonger time scale simulations of the behaviors of protein adsorptionat oil-water interfaces.