Small, water-soluble molecules with low vapor pressure can act to protect lipid membranes against osmotic stress. Such compounds, called osmolytes, occur naturally in many organisms to regulate osmotic pressure and to prevent cell damage due to freezing or drying. For example, urea, glycerol and pyrrolidone carboxylic acid (PCA) are a part of the Natural Moisturizing Factor in human skin, and are also used in skin care products. In seeds and plants, a class of protein named dehydrins are also present to protect against dehydration.
The question addressed in the project concerns the molecular mechanism(s) behind the role of the osmolytes and dehydrins in membrane systems under osmotic stress. By studying model lipid systems using a range of methods such as sorption calorimetry, sorption balance, X-ray diffraction/scattering and NMR we aim to unravel how the presence of different polar molecules and dehydrins interacts with phospholipid bilayers. We have previously studied urea and glycerol. In on-going studies, we explore the influence of dehydrins as well as other small polar molecules such as monosacharides, TMAO and PCA.