CONTROL OF MEMBRANE TRANSPORT BY OSMOTIC STRESS

我们测量了离子电池在开启和关闭过程中的内部体积变化 通过将不适当的溶质添加到通道的两侧来跨膜通道 含通道膜。航道开挖的额外工作 渗透应力是以电流-电压曲线的移位或以 通道的开启/关闭统计数据中的偏差。我们在测量体积 下面提到的频道的变化。我们已经开发出一种新的脂类 双层腔室，确保粘性溶液的良好混合，并减少 湍流可提高膜的稳定性。一种微型计算机数据 分析系统已适用于这些测量。 线粒体电压依赖性阴离子通道(VDAC)插入 平面脂双分子膜的体积变化在2万到4万立方米之间。 埃斯特罗姆。这是一个与传统屏蔽不同的重大变化 本地浇注模型，但支持模型的主要关闭 频道空间。此外，VDAC作为细胞内的一种 建议使用渗透压调节剂。 缝隙结是离子直接转移的轨迹和小的 分子从一个细胞到另一个细胞。为了衡量音量的变化，我们重建了 连接成平面膜。具有许多属性的频道 将连接通道成功地引入到平面膜中。 含有通道的囊泡的运输特异性纯化已经被 开发的目的是提高重建的效率。我们希望 区分两种已发布的基于间隙连接通道的模型 根据我们的音量变化测量。

We measure the internal volume change during opening and closing of ionic transmembrane channels by adding impermeant solutes to both sides of the channel-containing membrane. The extra work of channel opening under osmotic stress is measured as a shift in the current-voltage curve or as a bias in the open/closed statistics of a channel. We are measuring volume changes in the channels mentioned below. We have developed a new lipid bilayer chamber to ensure good mixing of viscous solutions and decreased turbulence leading to improved membrane stability. A microcomputer data analysis system has been adapted for these measurements. The mitochondrial voltage-dependent anion channel (VDAC) inserted into planar lipid bilayers shows a volume change of 20 to 40 thousand cubic angstroms. This is a large change inconsistent with traditional blocking of local gating models but supporting models with major closure of the channel space. In addition, the role of VDAC as an intracellular osmoregulator is suggested. The gap junction is the locus of direct transfer of ions and small molecules from cell to cell. To measure volume changes we reconstitute junctions into planar membranes. Channels with many of the properties of junctional channels were successfully incorporated into planar membranes. A transport-specific purification of vesicles containing channels has been developed to improve the efficiency of the reconstitution. We expect to distinguish between two published models of the gap junction channel based upon our volume-change measurements.