A large, voltage-dependent channel, isolated from mitochondria by water- free chloroform extraction
A large, voltage-dependent channel, isolated from mitochondria by water- free chloroform extraction
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DOI：
10.1529/biophysj.104.057281
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发表时间：
2005-04-01
影响因子：
3.4
通讯作者：
French, RJ
中科院分区：
文献类型：
--
作者：
Pavlov, E;Zakharian, E;French, RJ
我们研究了离子通道来自氯仿提取物的分离，脱水大鼠肝线粒体。提取方法先前用于分离含有聚-3-羟基丁酸酯和聚磷酸钙的来自大肠杆菌的通道形成复合物。这种复合物也存在于真核细胞膜中，并且主要位于线粒体中。重建的通道显示多个亚电导水平和电压依赖性，显示在接近零的电压更高的电导状态的概率增加。在对称的150 mM KCl中，通道的最大电导范围为350 pS至750 pS。对于>+/-60 mV的电压，电导在类似于50-类似于200 pS的范围内波动。在1：3的KCl梯度的存在下，在pH = 7.4时，选择性在不同状态之间周期性地切换，范围从弱阴离子选择性（V-rev类似于-15 mV）到理想阳离子选择性（V-rev类似于+29 mV），而其电导没有显著变化。总的来说，多样的，但高度可重复的，通道活性最接近的行为的渗透性转换孔通道中看到的膜片钳实验对本地线粒体。我们认为，孤立的复合物可能代表离子传导模块从渗透性转换孔。
We examined ion channels derived from a chloroform extract of isolated, dehydrated rat liver mitochondria. The extraction method was previously used to isolate a channel-forming complex containing poly-3-hydroxybutyrate and calcium polyphosphate from Escherichia coli. This complex is also present in eukaryotic membranes, and is located primarily in mitochondria. Reconstituted channels showed multiple subconductance levels and were voltage-dependent, showing an increased probability of higher conductance states at voltages near zero. In symmetric 150 mM KCl, the maximal conductance of the channel ranged from 350 pS to 750 pS. For voltages >+/-60 mV, conductance fluctuated in the range of similar to 50-similar to 200 pS. In the presence of a 1:3 gradient of KCl, at pH = 7.4, selectivity periodically switched between different states ranging from weakly anion-selective (V-rev similar to-15 mV) to ideally cation-selective (V-rev similar to +29 mV), without a significant change in its conductance. Overall, the diverse, but highly reproducible, channel activity most closely resembled the behavior of the permeability transition pore channel seen in patch-clamp experiments on native mitoplasts. We suggest that the isolated complex may represent the ion-conducting module from the permeability transition pore.