Activities of a mechanosensitive ion channel in an E. coli mutant lacking the major lipoprotein.
Activities of a mechanosensitive ion channel in an E. coli mutant lacking the major lipoprotein.
复制标题
缺乏主要脂蛋白的大肠杆菌突变体中机械敏感离子通道的活性。
DOI：
10.1007/bf02260105
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Kung,C
中科院分区：
文献类型：
--
作者：
Kubalski,A;Martinac,B;Ling,KY;Adler,J;Kung,C
弗罗姆.用膜片钳技术分析粘粒体。外膜缺乏主要脂蛋白（LPP）的突变体和它的野生型父母进行了检查。在野生型膜中的MS通道活动很少显示substates在所使用的时间分辨率。这些通道显示出由4.9 mm Hg吸力的IISP（通道打开概率增加1倍的吸力）指示的拉伸敏感性。的MS通道活动flpp包括一个突出的亚状态，并显示出较弱的机械敏感性与10.0毫米汞柱的1/Spo。而小的两亲分子（氯丙嗪，三硝基苯酚）或较大的两亲分子（lysolopaths）都激活MS通道在野生型膜在最小的吸力，只有较大的lysolopaths可以激活MS通道在thelpp膜。加入溶血素后，膜在向MS通道传递拉伸力方面变得更加有效，如Boltzmann曲线变陡所示。我们讨论了这些结果的一种解释，其中主要的脂蛋白作为一个天然的两亲分子插入在内部单层和这种天然的两亲分子的损失使得双层能够传输的门控力。
The activity of the mechanosensitive (MS) ion channels in membrane patches, excised fromE. colispheroplasts, was analyzed using the patch-clamp technique. Outer membranes from a mutant lacking the major lipoprotein (Lpp) and its wildtype parent were examined. The MS-channel activities in the wild-type membrane rarely revealed substates at the time resolution used. These channels showed a stretch sensitivity indicated by the IISP (the suction for ane-fold increase in channel open probability) of 4.9 mm Hg suction. The MS-channel activities oflppincluded a prominent substate and showed a weaker mechano-sensitivity with an 1/Spof 10.0 mm Hg. Whereas small amphipaths (chlorpromazine, trinitrophenol) or a larger amphipath (lysolecithin) all activated the MS channel in the wild-type membrane under minimal suction, only the larger lysolecithin could activate the MS channel in thelppmembranes. After lysolecithin addition, thelppmembrane became more effective in transmitting the stretch force to the MS channel, as indicated by a steepening of the Boltzmann curve. We discuss one interpretation of these results, in which the major lipoprotein serves as a natural amphipath inserted in the inner monolayer and the loss of this natural amphipath makes the bilayer less able to transmit the gating force.