Transfer of twelve charges is needed to open skeletal muscle Na+ channels.
Transfer of twelve charges is needed to open skeletal muscle Na+ channels.
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需要十二个电荷的转移以打开骨骼肌Na+通道。
DOI：
10.1085/jgp.106.6.1053
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发表时间：
1995-12
影响因子：
3.8
通讯作者：
Patlak, J
中科院分区：
文献类型：
--
作者：
Hirschberg, B;Rovner, A;Lieberman, M;Patlak, J
电压依赖性Na+通道被认为利用位于膜电场内的固定电荷来感测膜电位。作为膜电位的函数的开放概率（Po）的测量给出了在开放通道中移动通过场的这种电荷的数量的定量指示。我们已经使用单通道记录来测量骨骼肌Na+通道在其最负极端时的开放概率，其中通道可能每分钟开放一次。为了防止快速失活掩盖PO的电压依赖性，我们已经产生了一个克隆的大鼠骨骼肌Na+通道，缺乏快速失活（IFM 1303 QQQ）。使用这种突变的非洲爪蟾卵母细胞中表达的通道，和单通道分析所提供的额外分辨率，我们已经扩展了四个数量级的PO曲线的超极化尾部的分辨率。我们表明，以前的测量，这表明至少有六个有效的门控费用，可能已经在一个范围内的Po值尚未达到其极限斜率。在我们的准备中，至少12个电荷必须在通道的激活门控中起作用。我们的研究结果将需要重新评估的动力学模型的基础上，六个电荷，他们有重大影响的解释S4诱变研究和结构/功能模型的Na+通道。
Voltage-dependent Na+ channels are thought to sense membrane potential with fixed charges located within the membrane's electrical field. Measurement of open probability (Po) as a function of membrane potential gives a quantitative indication of the number of such charges that move through the field in opening the channel. We have used single- channel recording to measure skeletal muscle Na+ channel open probability at its most negative extreme, where channels may open as seldom as once per minute. To prevent fast inactivation from masking the voltage dependence of Po, we have generated a clone of the rat skeletal muscle Na+ channel that is lacking in fast inactivation (IFM1303QQQ). Using this mutant channel expressed in Xenopus oocytes, and the extra resolution afforded by single-channel analysis, we have extended the resolution of the hyperpolarized tail of the Po curve by four orders of magnitude. We show that previous measurements, which indicated a minimum of six effective gating charges, may have been made in a range of Po values that had not yet arrived at its limiting slope. In our preparation, a minimum of 12 charges must function in the activation gating of the channel. Our results will require reevaluation of kinetic models based on six charges, and they have major implications for the interpretation of S4 mutagenesis studies and structure/function models of the Na+ channel.
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DOI：
10.1085/jgp.77.1.1
发表时间：
1981-01
期刊：
The Journal of general physiology
影响因子：
--
作者：
Oxford GS
通讯作者：
Oxford GS
影响因子：
5.5
作者：
HODGKIN, AL;HUXLEY, AF
通讯作者：
HUXLEY, AF
DOI：
10.1073/pnas.89.22.10910
发表时间：
1992-11-15
影响因子：
11.1
作者：
WEST, JW;PATTON, DE;CATTERALL, WA
通讯作者：
CATTERALL, WA
振动钾通道门控。 II：激活途径中的过渡。
DOI：
10.1085/jgp.103.2.279
发表时间：
1994-02
期刊：
The Journal of general physiology
影响因子：
--
作者：
Zagotta WN;Hoshi T;Dittman J;Aldrich RW
通讯作者：
Aldrich RW
影响因子：
64.8
作者：
NODA, M;SHIMIZU, S;NUMA, S
通讯作者：
NUMA, S