Conductance of Poly-3-hydroxybutyrate/calcium Polyphosphate Complexes in Planar Bilayers

本研究旨在研究聚乙烯复合物的性质， 羟基丁酸/聚磷酸钙和非共价缔合 平面脂质双层中的蛋白质。初步证据 这个膜区域可能参与钙的调节， 基于对细胞培养物和单个 细胞该复合体广泛存在于原核生物中， 在真核生物的线粒体中。据推测， 溶剂化聚阴离子盐并形成离子传导复合物 这可能导致钙从细胞中去除， 同时去除磷酸盐。电压依赖性钙离子 复合物的电导率。大肠杆菌将研究在平面 脂质双层。阳离子选择性与通道作用 还将确定封闭剂。 %%% 细菌含有大量的聚羟基丁酸酯复合物 和多磷酸钙。这个复合体的组成表明 聚羟基丁酸酯可以溶剂化聚阴离子（负性 带电）复合物，并允许它们通过螺旋移动 被认为是形成的通道，从而去除钙， 聚磷酸盐从内部到外部。这种可能性 可以通过将复合物放入平面脂质双层中进行检查， 其可用作细胞质膜的模型，和 改变环境的条件。离子组成 所施加的电荷都是变化的， 将评估这些变化的影响。很可能 这种复合物也存在于高等生物中， 对钙的调节。由于钙浓度非常高， 重要的细胞功能，这些研究应该是有用的， 了解细胞内钙变化的新机制。

This proposal is to study the properties of complexed poly- hydroxybutyrate/calcium polyphosphate and non-covalently associated proteins in planar lipid bilayers. There is preliminary evidence that this membrane domain may be involved in calcium regulation, based on spectrofluorometric studies in cell cultures and single cells. The complex is widespread in prokaryotes and may be present in mitochondria of eukaryotes. It is hypothesized to act by solvating polyanionic salts and forming ion-conducting complexes which could result in the removal of calcium from the cell, with simultaneous removal of phosphate. The voltage-dependent calcium conductance of the complex from E. coli will be studied in planar lipid bilayers. The cation selectivity and the action of channel blocking agents will also be determined. %%% Bacteria contain large amounts of a complex of polyhydroxybutyrate and calcium polyphosphate. The composition of this complex suggests that the polyhydroxybutyrate could solvate polyanionic (negatively charged) complexes and allow them to move through the helical channel which is thought to be formed, thus removing calcium and polyphosphate from the interior to the exterior. This possibility can be examined by putting the complex into a planar lipid bilayer, which can be used as a model of the plasma membrane of cells, and changing the conditions in the environment. The ionic composition and the electrical charge applied will both be varied, and the effects of these variations will be assessed. It seems likely that this complex is also present in higher organisms, and may function in regulation of calcium. Since calcium concentration is very important in cellular function, these studies should be useful in understanding a new mechanism for varying intracellular calcium.