PROTEIN-LIPID INTERACTION - BIOPHYSICAL STUDIES OF (CA2+ + MG2+)-ATPASE RECONSTITUTED SYSTEMS
PROTEIN-LIPID INTERACTION - BIOPHYSICAL STUDIES OF (CA2+ + MG2+)-ATPASE RECONSTITUTED SYSTEMS
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DOI：
10.1016/0005-2736(80)90031-0
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发表时间：
1980-01-01
期刊：
影响因子：
--
通讯作者：
CHAPMAN, D
中科院分区：
文献类型：
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作者：
GOMEZFERNANDEZ, JC;GONI, FM;CHAPMAN, D
差示扫描量热法，荧光光谱和冷冻断裂EM应用于研究重组的Ca 2 +-ATP酶蛋白质从[兔]肌浆网时，他们被纳入纯脂质/水系统。用这些技术获得的结果被用来检查这种intrinisc蛋白对周围的脂质在温度高于和低于主要脂质的固-液相变温度（Tc）的影响。高于此Tc值，冷冻断裂数据表明，蛋白质随机分布在双层的平面内。荧光数据表明，随着双层中蛋白质含量的增加，微粘度也增加。低于Tc时，蛋白质以高蛋白脂质斑块的形式出现，与剩余的结晶脂质分离。荧光数据表明，在这些温度下，蛋白质的存在导致微粘度降低，而量热数据表明主要脂质转变的焓降低。量热和荧光数据表明，在脂质双层内通过相分离形成的高蛋白质到脂质斑块的预熔融。这一观察结果被用来合理化二棕榈酰磷脂酰胆碱-ATP酶在远低于41 ℃的脂质相变温度下显示活性的异常性质。C.
Differential scanning calorimetry, fluorescence spectroscopy and freeze-fracture EM were applied to a study of the reconstituted Ca2+-ATPase proteins from [rabbit] sarcoplasmic reticulum when they are incorporated into pure lipid/water systems. The results obtained with these techniques were used to examine the effects of this intrinisc protein upon the surrounding lipid at temperatures above and below the main lipid solid-fluid phase transition temperature (Tc). Above this Tc value, the freeze-fracture data show that the proteins are randomly distributed within the plane of the bilayer. The fluorescence data show that as the protein content in the bilayer increases, the microviscosity does also. Below Tc, the proteins occur in high protein to lipid patches separate from the remaining crystalline lipid. The fluorescence data indicate that at these temperatures the presence of the protein causes a decrease in microviscosity, while the calorimetric data indicate a decrease in enthalpy of the main lipid transition. A premelting of the high protein to lipid patches formed by phase separation within the lipid bilayers is indicated by the calorimetric and fluorescence data. This observation is used to rationalize the anomalous properties of the dipalmitoyl phosphatidylcholine-ATPase of exhibiting activity at temperatures well below the lipid phase transition at 41.degree. C.