Aqueous micellar systems in membrane protein crystallization. Partial miscibility of a nonionic surfactant in the presence of salt or polyethylene glycol.
The effects of NaCl and polyethylene glycol (PEG) 4000 on the lower consolution boundary (LCB) of a nonionic surfactant (C8E5) were studied and compared. Micellar systems were NaCl and PEG 4000 are present are often used in membrane protein crystallization. While sodium chloride shifts the surfactant LCB to lower temperatures without a significant change in the shape of the boundary, PEG produces a large solubility change strongly depending on the surfactant concentration. The salt effect is explained by a reduced interaction of the micellar oligooxyethylene chains with the water and the PEG effect by an unfavourable configurational interaction between the C8E5 micelles and PEG molecules.
D003460:Crystallization; D008565:Membrane Proteins; D008823:Micelles; D008954:Models, Biological; D011092:Polyethylene Glycols; D011663:Pulmonary Surfactants; D012965:Sodium Chloride; D012995:Solubility
D008565:Membrane Proteins; D008823:Micelles; D011663:Pulmonary Surfactants; D011092:Polyethylene Glycols; D012965:Sodium Chloride