In meso crystallization: compatibility of different lipid bicontinuous cubic mesophases with the cubic crystallization screen in aqueous solution

In meso crystallization uses bicontinuous cubic lipidic mesophases as matrices for the crystallization of membrane proteins. In this work, we look at the impact of a screen specifically marketed as compatible with the cubic mesophase, the Cubic crystallization screen (Emerald BioSystems), on the cubic mesophases formed by three different lipids: monoolein, monopalmitolein, and phytantriol. The Cubic screen was found to be compatible with cubic mesophase retention under most crystallization conditions for all three lipids studied. The effect of the individual components comprising the multicomponent screen was deconvoluted in two ways. Initially, the effect of specific poly(ethylene glycol) (PEG) and salt components on the cubic mesophase was determined using small-angle X-ray scattering (SAXS). The effect of high-molecular-weight (M_w) PEG was shown to dominate the phase behavior within the screen. The effect of additional salts present within the screen becomes important for low M_w PEG molecules. Finally, a recently developed multiple linear-regression modeling method was shown to deconvolute the effect of individual components within the screen effectively.