【作者】 彭庆；

【导师】 彭玲；

【作者基本信息】 武汉大学 ， 有机化学， 2004， 硕士

【摘要】 生物膜（biomembranes）是由具有双层结构的类脂分子和镶嵌在其中的膜蛋白所共同构成的。类脂分子以磷脂中的甘油磷脂（glycerophospholipids,GPLs）为主要成分。它在与细胞膜有关的各种生命过程中扮演了重要角色,并且还承担多种生理功能,包括信号传递、病毒感染、营养作用以及治疗作用等。膜蛋白是细胞膜的另一种主要组成成分。它与脂双层膜一同参与并调控许多重要的生物功能,如信号传递、能量转化、离子运输以及分子过膜运动等。此外,膜蛋白是一类非常重要的药物靶标分子。因此研究膜蛋白的拓扑结构以及膜蛋白和膜脂分子之间的相互作用（protein-lipid interactions）,对于我们了解膜蛋白的结构和功能又至关重要。 由于膜蛋白的X射线晶体衍射数据和高分辨核磁（high-resolution NMR）数据难以得到,因此,我们迫切需要用其它相关方法来研究膜蛋白的拓扑结构以及膜蛋白和膜脂分子之间的相互作用。我们认为,利用光敏磷脂探针对膜蛋白进行光亲合标记研究是一种有效的研究膜蛋白的方法。 芳基叠氮化合物因其易于制备、黑暗中稳定、光照下产生高活性反应中间体等优点而被广泛应用于光亲合标记研究中。与普通的芳基叠氮基团相比,全氟取代的芳基叠氮基团具有更高的光标记效率;而香豆素（coumarine）的叠氮衍生物则同时具有荧光标记能力和光亲合标记能力,具有更广泛的应用潜力。目前,尽管已经有一些磷脂光敏探针用于膜蛋白研究的报道,但是还没有使用以上两种芳基叠氮基团作为光敏基团的报道,在磷脂的极性头基上引入光敏基团的报道也极少见。 本论文工作中,我们成功地分别在天然磷脂的结构中引入了全氟取代的芳基叠氮基团和叠氮取代的香豆素（coumarine）基团作为光敏基团,合成了8个光敏基团位于磷脂极性头基的光敏磷脂探针和一个光敏基团位于磷脂非极性尾端的光敏磷脂探针。并通过¹H NMR、¹³C NMR、IR、UV和MS对它们进行了表征。 对于所得到的9个光敏磷脂探针,我们都进行了光化学性质的检测。这9个光敏磷脂探针无一例外的表现出非常良好的光化学活性。它们的最大吸收波长更多还原

【Abstract】 Biomembranes are composed of lipid bilayers and membrane proteins. The phospholipids are the major components of the lipids. Phospholipids are involved in many important biological processes of biomembranes and themselves have many biological and physiological functions such as signal transduction, virus infection and nutrition.Membrane proteins associate with biomembrane lipid bilayers and mediate important biological functions, such as signal transduction, energy conversion, transport of ions and molecules across the membrane. They are important targets for drug developmen. Understanding the structures and functions of these membrane proteins is therefore important for searching novel therapeutic targets as well as pursuing drug development programs. It is therefore necessary to be able to obtain direct, reliable evidence about the topology of membrane proteins and protein-lipid interactions. Since it’s difficult to get the X-ray crystallography data and high-resolution NMR data of membrane proteins, we propose photo-affinity labeling of biomembranes with photoactivatable phospholipidic probes.We have therefore synthesized and characterized a series of photoactivatable phospholipidic probes. They have either the coumarin azide group or fluorinated aryl azide group at the lipid polar head or on the fatty acid chain of phospholipids.Aryl azides are by far the most frequently used photoaffinity probes because they can be easily synthesized, as well as being chemically stable in the dark and highly reactive upon photoirradiation. Among the arylazides, fluorinated aryl azides are exceptionally promising because upon photoactivation, they lead to much more efficient photolabeling than non-fluorinated arylazides. Furthermore, the coumarine derivatives with azide group is of special interest because they can be used as both photoaffinity probes and fluorescent probes. Several phospholipidic probes have been previously synthesized with various photoactiovatable groups on the fatty acid chainor at the polar head. However, so far to our knowledge, no phospholipidic probes have been developed based on fluorinated aryl azide or coumarine azide.The photochemistry of the probes was studied in organic solvents and in phosphate buffer. All probes underwent rapid and clean photodecomposition upon irradiation at > 300 nm, at which most biological macromolecules will not be damaged by UV irradiation. Further, the probes with a coumarine azide group can be used as both photoaffinity probes and fluorescent probes, allow us to follow the photolabeling process by fluorescent detection. Therefore, our photochemical results showed that these probes hold promises for the photolabeling studies of biomembranes.更多还原