Moe P C, Blount P, Kung C
Laboratory of Molecular Biology and Department of Bacteriology, University of Wisconsin-Madison, 53706, USA.
Mol Microbiol. 1998 May;28(3):583-92. doi: 10.1046/j.1365-2958.1998.00821.x.
mscL encodes a channel in Escherichia coli that is opened by membrane stretch force, probably serving as an osmotic gauge. Sequences more or less similar to mscL are found in other bacteria, but the degree of conserved function has been unclear. We subcloned and expressed these putative homologues in E. coli and examined their products under patch clamp. Here, we show that each indeed encodes a conserved mechanosensitive channel activity, consistent with the interpretation that this is an important and primary function of the protein in a wide range of bacteria. Although similar, channels of different bacteria differ in kinetics and their degree of mechanosensitivity. Comparison of the primary sequence of these proteins reveals two highly conserved regions, corresponding to domains previously shown to be important for the function of the wild-type E. coli channel, and a C-terminal region that is not conserved in all species. This structural conservation is providing insight into regions of this molecule that are vital to its role as a mechanosensitive channel and may have broader implications for the understanding of other mechanosensitive systems.
mscL在大肠杆菌中编码一种通道，该通道由膜拉伸力打开，可能充当渗透压计。在其他细菌中发现了与mscL或多或少相似的序列，但保守功能的程度尚不清楚。我们将这些假定的同源物亚克隆并在大肠杆菌中表达，并在膜片钳下检查它们的产物。在这里，我们表明每个确实编码一种保守的机械敏感通道活性，这与该蛋白在广泛细菌中具有重要和主要功能的解释一致。尽管相似，但不同细菌的通道在动力学及其机械敏感程度上有所不同。这些蛋白质一级序列的比较揭示了两个高度保守的区域，对应于先前显示对野生型大肠杆菌通道功能很重要的结构域，以及一个在所有物种中都不保守的C末端区域。这种结构保守性为该分子作为机械敏感通道发挥作用的关键区域提供了见解，并且可能对理解其他机械敏感系统具有更广泛的意义。
