Artificial Model for Inter-cellular communications

在许多组织中，细胞间通讯是由一种叫做间隙连接的主要内在蛋白介导的。对间隙连接蛋白序列的分析表明，它通过跨膜两亲性螺旋穿过脂质双分子层，这对于细胞间水通道的形成至关重要。在本研究中，我们采用“单层反应法”制备了由两个两亲性螺旋连接在它们之间的亲水间隔物组成的多肽，并以间隙连接模型考察了其对囊间水通道形成的活性。以1,3-二氨基- 2-丙醇为引发剂，在1,2-二氯乙烷中聚合l -谷氨酸乙甲酯n -羧酸酐，制得起始原料MPrM。然后采用单层反应法对MPrM进行皂化，使其具有两亲性，即am-MPrM。从双棕榈酰磷脂酰胆碱中am-MPrM的CD光谱、凝胶过滤分析和D_2O的囊间转运可知，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，并在膜上相互结合形成水通道，可以有效地进行D_2O的微注射。多肽的囊泡识别能力将需要更现实的模型系统。

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.