Fast inactivation of Shaker K+ channels is highly temperature dependent.
Fast inactivation of Shaker K+ channels is highly temperature dependent.
复制标题
Shaker K 通道的快速失活高度依赖于温度。
DOI：
10.1007/pl00005613
复制
发表时间：
1997
影响因子：
2
通讯作者：
Stefani,E
中科院分区：
文献类型：
--
作者：
Nobile,M;Olcese,R;Toro,L;Stefani,E
研究了NH 2-末端失活结构域与ShakerH 4 K+通道内口之间相互作用的能量分布。使用切开卵母细胞技术，在不同温度下记录来自正常失活通道（ShakerH 4）和去除失活通道（ShakerH 4-IR）的宏观电流。温度变化对灭活阶段有显著影响。在摇床H_4中，温度从20°C降至5°C时，（1）峰振幅随温度系数Q_（10）= 1.51而减小，（2）活化时间常数随温度系数Q_（10）= 3.14而增大;（3）衰减时间常数随着aQ_（10）= 7.20而增大，而从失活的恢复是较少的温度依赖性（Q10=1.57）比灭活阶段的安装。在0 mV时，稳态水平与电流峰值幅度之间的比率随着aQ 10为2.95而增加。这些发现表明，安装一个快速灭活过程具有很强的温度依赖性，而从失活的恢复阶段是温度依赖性较低。这些观察结果支持的想法的NH 2-末端阻断机制的灭活和灵活的构象的阻断颗粒。
The energy profile of the interaction between the NH2-terminal inactivation domain and the internal mouth of theShakerH4 K+channel has been investigated. Macroscopic currents from channels normally inactivating (ShakerH4) and with the inactivation removed (ShakerH4-IR) were recorded at different temperatures using the cut-open oocyte technique. Changes in temperature had a dramatic effect on the inactivation phase. The following parameters were obtained inShakerH4, lowering the temperature from 20°C to 5°C: (1) the peak amplitude decreased with the temperature coefficientQ10equal to 1.51; (2) the activation time constant increased with aQ10equal to 3.14; (3) the decay time constant increased with aQ10of 7.20, while the recovery from inactivation was less temperature-dependent (Q10=1.57) than the installation of the inactivation phase. At 0 mV, the ratio between the steady state level and the peak amplitude of the current increased with aQ10of 2.95. These findings indicate that the installation of a fast inactivation process has a strong temperature dependence, while the recovery phase from inactivation is less temperature dependent. These observations support the idea of an NH2-terminal blocking mechanism for inactivation and flexible conformation of the blocking particle.