Kutchai H, Chandler L H, Zavoico G B
Biochim Biophys Acta. 1983 Dec 21;736(2):137-49. doi: 10.1016/0005-2736(83)90277-8.
Phase modulation fluorescence spectroscopy was used to investigate the influence of cholesterol (0 to 50 mol%) on acyl chain dynamics in multilamellar vesicles of phosphatidylcholine. Four different phosphatidylcholines (DPPC, DOPC, POPC, and egg PC) and six different fluorescent probes (diphenylhexatriene and five anthroyloxy fatty acids) were employed. We found that: (1) Increased cholesterol content had only slight effects on fluorescence lifetimes of the six probes. (2) Increased cholesterol content increased the steady-state fluorescence anisotropy (r) of all the probes except 16-anthroyloxy palmitate (16-AP) in each of the four phosphatidylcholines. (3) Added cholesterol tended to limit the extent of probe rotation (as reflected by r infinity, the infinite-time anisotropy) to a much greater extent than it altered the rate of probe rotation. (4) The tendency for cholesterol to order the structure of the bilayer was greatest in the proximal half of the acyl chains and diminished toward the center of the bilayer. (5) In some phosphatidylcholines the rotations rates of probes located near the bilayer center (diphenylhexatriene and 16-AP) were apparently increased by increasing levels of cholesterol. (6) In several respects dipalmitoylphosphatidylcholine (DPPC) vesicles responded differently to increased cholesterol than vesicles of the other three phosphatidylcholines. (7) A single second-order equation described the relationship between r infinity and r for the five anthroyloxy fatty acid probes in the four different phosphatidylcholines over a wide range of cholesterol content. The data for diphenylhexatriene in the different phosphatidylcholines could not be fit by a single equation.
采用相位调制荧光光谱法研究了胆固醇（0至50摩尔%）对磷脂酰胆碱多层囊泡中酰基链动力学的影响。使用了四种不同的磷脂酰胆碱（二棕榈酰磷脂酰胆碱、二油酰磷脂酰胆碱、1-棕榈酰-2-油酰磷脂酰胆碱和蛋黄卵磷脂）以及六种不同的荧光探针（二苯基己三烯和五种蒽氧基脂肪酸）。我们发现：（1）胆固醇含量增加对六种探针的荧光寿命仅有轻微影响。（2）胆固醇含量增加使四种磷脂酰胆碱中除16-蒽氧基棕榈酸酯（16-AP）外的所有探针的稳态荧光各向异性（r）增加。（3）添加胆固醇倾向于比改变探针旋转速率更大程度地限制探针旋转程度（由r∞，即无限时间各向异性反映）。（4）胆固醇使双层结构有序化的趋势在酰基链的近端一半最大，向双层中心逐渐减弱。（5）在某些磷脂酰胆碱中，位于双层中心附近的探针（二苯基己三烯和16-AP）的旋转速率显然因胆固醇水平升高而增加。（6）在几个方面，二棕榈酰磷脂酰胆碱（DPPC）囊泡对胆固醇增加的反应与其他三种磷脂酰胆碱的囊泡不同。（7）一个二阶方程描述了在广泛的胆固醇含量范围内，四种不同磷脂酰胆碱中五种蒽氧基脂肪酸探针的r∞与r之间的关系。不同磷脂酰胆碱中二苯基己三烯的数据不能用一个方程拟合。
