EFFECTS OF CAROTENOIDS ON PHYSICAL PROPERTIES OF LIPID BILAYER MEMBRANES

我们研究了类胡萝卜素（刚性，棒状） 分子的长度与膜的厚度相当，但 分子末端的不同极性基团），β-胡萝卜素 （非极性）、隐黄质（一端上的极性-OH基团）、玉米黄质或 叶黄素（两端的极性-OH基团）在烷基链顺序和 运动、相变和膜内部的极性。 作为 模型膜，我们使用饱和磷脂酰胆碱（PC）与 不同的烷基链长度（DKPC-12个碳; DMPC-14; DPPC-16; DSPC-18;和DBPC-22碳）和不饱和PCS、DOPC和大豆 PC. 我们使用硬脂酸自旋标记与氮氧部分位于 沿烷基链的沿着不同位置。 我们的结果显示 将类胡萝卜素分子锚定在膜的一侧或两侧， 膜对于有效的膜-类胡萝卜素相互作用是重要的。 非极性β-类胡萝卜素对细胞膜的影响很小 结构和运动。 然而，初步数据显示， 膜可溶性肽的存在（膜的简单模型 β-胡萝卜素的短杆菌肽效果与 极性类胡萝卜素。

We investigated the effects of carotenoids (rigid, rod-like molecules with a length comparable to the membrane thickness but with different polar groups on the ends of the molecule), beta-carotene (non-polar), cryptoxanthin (polar -OH group on one end), zeaxanthin or lutein (polar -OH groups on both ends) on alkyl chain order and motion, phase transition, and polarity of the membrane interior. As model membranes we used saturated phosphatidylcholines (PC) with different alkyl chain lengths (DKPC-12 carbons; DMPC-14; DPPC-16; DSPC-18; and DBPC-22 carbons) and unsaturated PCS, DOPC and soybean PC. We used stearic acid spin labels with nitroxide moiety located at different positions along the alkyl chain. Our results show that anchoring of the carotenoid molecule on one side or both sides of the membrane is significant for effective membrane-carotenoid interaction. Nonpolar beta-carotenoid exerts only a minor effect on membrane structure and motion. Preliminary dat a sh ow, however, that in the presence of membrane-soluble peptides (simple model of membrane proteins) gramicidin effects of beta-carotene are comparable with those of polar carotenoids.