The influence of surface charges on the conductance of the human connexin37 gap junction channel
The influence of surface charges on the conductance of the human connexin37 gap junction channel
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DOI：
10.1016/s0006-3495(00)76633-1
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发表时间：
2000-02-01
影响因子：
3.4
通讯作者：
Brink, PR
中科院分区：
文献类型：
--
作者：
Banach, K;Ramanan, SV;Brink, PR
hCx 37同型间隙连接通道的单通道电导在高达+/-75 mV的跨接电压下不饱和，也不线性依赖于细胞内电解质浓度。在KCl中测量的平均最大单位电导在0.1 mM MgCl 2存在下为175 pS（30 mM）、236 pS（55 mM）、343 pS（110 mM）和588 pS（270 mM）。在低盐浓度下的出乎意料的高单位电导可以通过通道孔内或附近的固定电荷基团来解释。位于通道孔附近（15埃）的固定细胞质表面电荷（3.4 e）充分模拟了数据（表面电荷密度为0.24 e/（nm）（2））。在其他实验中，高Mg 2+降低hCx 37同型间隙连接通道的单位电导比单独筛选预测的更多，这与Mg 2+对通道的特定影响一致。
The single-channel conductance of the hCx37 homotypic gap junction channel does not saturate with transjunctional voltages up to +/-75 mV, nor does it depend linearly on the intracellular electrolyte concentration. The average maximum unitary conductances measured in KCI were 175 pS (30 mM), 236 pS (55 mM), 343 pS (110 mM), and 588 pS (270 mM) in the presence of 0.1 mM MgCl2, The unexpectedly high unitary conductance at low salt concentrations can be explained by fixed charge groups within or near the channel orifice. Fixed cytoplasmic surface charges (3.4 e) positioned adjacent (15 Angstrom) to the channel pore adequately model the data (surface charge density of 0.24 e/(nm)(2)). In other experiments, high Mg2+ reduced the unitary conductance of hCx37 homotypic gap junction channels more than predicted by screening alone, consistent with specific effects of Mg2+ on the channel.