Impacts of Lipase Enzyme on the Surface Properties of Marine Aerosols

Triacylglycerol lipases have recently been shown to be transferred from the ocean to the atmosphere in atmospheric sea spray aerosol (SSA). Lipases have the potential to alter the composition of SSA; however, the structure and properties of enzymes in the high salt, high ionic strength, and low pH conditions found in SSA have never been explored. Here, we study the dynamics of <i>Burkholderia cepacia</i> triacylglycerol lipase (BCL) at SSA model surfaces comprised of palmitic acid and dipalmitoylphosphatidic acid (DPPA), two commonly found lipids at SSA surfaces. Surface adsorption Langmuir isotherm experiments and all-atom explicit solvent molecular dynamics simulations together illuminate how and why BCL expands the ordering of lipids at palmitic acid surfaces the most at pH < 4 and the least in DPPA surfaces at pH 6. Taken together, these results represent a first glimpse into the complex interplay between lipid surface structure and protein dynamics within enzyme-containing aerosols