PLANAR BILAYER CONDUCTANCE AND FLUORESCENCE STUDIES CONFIRM THE FUNCTION AND LOCATION OF A SYNTHETIC, SODIUM-ION-CONDUCTING CHANNEL IN A PHOSPHOLIPID BILAYER MEMBRANE
PLANAR BILAYER CONDUCTANCE AND FLUORESCENCE STUDIES CONFIRM THE FUNCTION AND LOCATION OF A SYNTHETIC, SODIUM-ION-CONDUCTING CHANNEL IN A PHOSPHOLIPID BILAYER MEMBRANE
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平面双层电导和荧光研究证实了磷脂双层膜中合成钠离子传导通道的功能和位置
DOI：
10.1021/ja971098t
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发表时间：
1997
影响因子：
15
通讯作者：
G. Gokel
中科院分区：
文献类型：
--
作者：
Ernesto Abel;G. E. Maguire;E. S. Meadows;Oscar Murillo;T. Jin;G. Gokel
跨越细胞膜并介导阳离子、阴离子和分子跨越细胞和细胞器边界的转运的蛋白质对所有生命都至关重要。这使得跨膜离子通道的研究成为现代生物化学中最活跃的领域之一。1,2这一领域的根本重要性以及有关渠道功能的机械问题怎么强调都不为过。尽管已经积累了大量关于哪些蛋白质负责转运的信息，但转运和选择性的物理化学细节在很大程度上仍然是模糊的。超分子化学允许设计化合物，使其具有与自然系统中明显的化合物相似的性质，但可以对其进行更详细的研究。这些原理已被us5和其他人应用于合成通道模型系统的开发中。我们现在报告了两种新型的、合成的、含有荧光探针的阳离子导电通道化合物。这允许对模型通道在磷脂双分子层中的位置进行首次评估。我们提出了三条与通道化合物在双分子层内的位置有关的证据。这些是(1)荧光头基团的溶剂转移，(2)尝试的能量转移，(3)使用羟基标记的脂质。通过膜片钳放大器和双层头级获得的通道化合物诱导的膜通透性数据也包括在内。后者证实了所研究化合物的功能。本研究制备的化合物1和2均为R< N18N> C12< N18N> C12< N18N> R，其中R为2-（3- n -甲酰基）乙基（MeInE, 1）或8-（二甲氨基）萘磺酰基（dansyl, Dn, 2）。1的合成是由3-（2-溴乙基）吲哚与CH3I （NaH, 91%，无色油）烷基化完成的。溴乙基吲哚与4,13 -二氮杂-18-冠-6反应得到N-（N-甲基-3-）
Proteins that span membranes and mediate the transport of cations, anions, and molecules across the boundaries of cells and organelles are crucial to all life. This fact has made the study of transmembrane ion channels one of the most active areas in modern biological chemistry. 1, 2 The fundamental importance of this area and of the mechanistic questions concerning channel function cannot be overstated. Despite the enormous amount of information that has accumulated concerning which proteins are responsible for transport, physical chemical details of transport and selectivity remain largely obscure. 3 Supramolecular chemistry permits the design of compounds that possess properties similar to those apparent in natural systems but which can be studied in greater detail. 4 These principles have been applied in the development of synthetic channel model systems by us5 and by others. 6 We now report two novel, synthetic, cation-conducting channel compounds that incorporate fluorescent probes. 7 This permits the first assessment of a model channel’s position within a phosphilipid bilayer. We present three lines of evidence that relate to the channel compound’s position within the bilayer. These are (1) solvent shift of the fluorescent headgroup,(2) attempted energy transfer, and (3) the use of doxyl-labeled lipids. Data are also included that show the membrane permeability induced by one of the channel compounds, obtained by using a patch clamp amplifier and a bilayer head stage. The latter confirms the function of the compounds under study.Compounds 1 and 2, prepared for the present study, were both of the form R< N18N> C12< N18N> C12< N18N> R in which R is 2-(3-N-methylindolyl) ethyl (MeInE, 1) or 8-(dimethylamino) naphthalenesulfonyl (dansyl, Dn, 2). 8 Synthesis of 1 was accomplished by alkylation of 3-(2-bromoethyl) indole with CH3I (NaH, 91%, colorless oil). Reaction of the (bromoethyl) indole with 4, 13-diaza-18-crown-6 gave N-(N-methyl-3-