Artificial Model for Inter-cellular communications

在许多组织中，细胞间的通讯是由一种称为缝隙连接的主要内在蛋白质介导的。对缝隙连接蛋白序列的分析表明，缝隙连接蛋白通过跨膜两亲性螺旋穿过脂质双层，这是形成细胞间水通道所必需的。在本研究中，我们应用“单层反应”方法制备了由两个两亲性螺旋连接而成的多肽，并考察了其形成泡间水通道的活性作为缝隙连接模型。起始原料是以1，3-二氨基异丙醇为引发剂，在1，2-二氯乙烷中聚合得到的。然后用单层反应法皂化mPRm，使其具有两亲性，即AM-mPRm。根据Am-mPrm在二棕榈酰磷脂酰胆碱中的圆二色谱、凝胶过滤分析和D_2O的囊间转运分析，可以得出结论：Am-mPRm将其两个两亲性螺旋分别结合到不同囊泡的双层膜上，诱导囊泡黏附，并在膜上相互缔合形成水通道，通过该通道可以有效地进行D_2O的微量注射。多肽的囊泡识别能力将被要求建立更逼真的模型系统。

Intercellular communication is mediated in many tissues by a major intrinsic protein called gap junction. It has been suggested, from analysis of the sequence of the gap junction protein, that it traverses the lipid bilayer via a transmembrane amphiphilic helix, which is essential for the formation of an intercellular aqueous channel. In the present study, we applied "Monolayer reaction method" to the preparation of the polypeptide composed of two amphiphilic helices jointed with a hydrophilic spacer between them, and examined its activity for the formation of an inter-vesicular aqueous channel as a gap junction model.The starting material, MPrM, was obtained by polymerization of the N-carboxy anhydride of L-glutamic acid eta-methyl ester with 1,3-diamino 2-propanohol as an initiator in 1,2-dichloroethane. And then MPrM was saponified by using the monolayer reaction method to give the amphiphilic nature to MPrM, am-MPrM. It can be concluded, from CD spectra of am-MPrM in dipalmitoylphosphatidylcholine, gel filtration analysis and inter-vesicular transport of D_2O, that am-MPrM incorporates its two amphiphilic helices to the bilayer membrane of different vesicles, respectively, to induce the vesicular adhesion and then associates each other in the membranes to form an aqueous channel, through which the micro-injection of D_2O can be effectively made. The vesicular recognition ability of the polypeptide will be required to make more realistic model systems.