Francis S E, Lyle I G, Jones M N
Department of Biochemistry and Molecular Biology, University of Manchester, U.K.
Biochim Biophys Acta. 1991 Feb 25;1062(2):117-22. doi: 10.1016/0005-2736(91)90382-i.
Proteoliposomes have been prepared from mixtures of dipalmitoylphosphatidylcholine and phosphatidylinositol by sonication (SUV) and reverse phase evaporation (REV) and conjugated with succinyl concanavalin A (sConA). The proteoliposomes were characterised in terms of size and composition and covered a range of size (weight-average diameter) from approx. 80 to 300 nm and surface-bound sConA (weight-average number of protein molecules per liposome) from approx. 200 to 1800. The permeabilities of the proteoliposomes to encapsulated D-glucose have been measured and found to increase linearly with protein conjugation. The D-glucose permeability also increases with temperature and passes through a maximum in the region of the gel to liquid-crystalline phase transition temperature. Conjugation has no effect on the chain-melting temperature but slightly decreases the enthalpy of the transition consistent with the withdrawal of some phospholipid participation in chain-melting. The D-glucose permeabilities and thermotropic properties of the proteoliposomes are discussed in terms of the dislocation of the bilayer by the possible off-axis motion of the lipid which anchors the protein to the liposomal surface.
通过超声处理（小单层囊泡）和反相蒸发法（大单层囊泡），由二棕榈酰磷脂酰胆碱和磷脂酰肌醇的混合物制备了蛋白脂质体，并与琥珀酰伴刀豆球蛋白A（sConA）偶联。对蛋白脂质体的大小和组成进行了表征，其大小范围（重均直径）约为80至300nm，表面结合的sConA（每个脂质体蛋白分子的重均数量）约为200至1800。已测量了蛋白脂质体对包封的D - 葡萄糖的渗透性，发现其随蛋白质偶联呈线性增加。D - 葡萄糖渗透性也随温度升高而增加，并在凝胶到液晶相转变温度区域出现最大值。偶联对链熔化温度没有影响，但略微降低了转变焓，这与一些磷脂参与链熔化的减少一致。根据脂质将蛋白质锚定到脂质体表面时可能的离轴运动导致双层错位，讨论了蛋白脂质体的D - 葡萄糖渗透性和热致性质。
