Regulation of CFTR ion channel gating by MgATP
Regulation of CFTR ion channel gating by MgATP
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DOI：
10.1016/s0014-5793(98)00713-3
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发表时间：
1998-07-10
期刊：
影响因子：
3.5
通讯作者：
Riordan, JR
中科院分区：
文献类型：
--
作者：
Aleksandrov, AA;Riordan, JR
记录在脂质双层中重建的野生型 CFTR 的单通道电流，以研究 +20 摄氏度和 +40 摄氏度之间通道门控的温度依赖性。通道的打开高度依赖于温度，需要约 100 kJ/mol 的激活能。通道的关闭仅与温度有微弱的相关性，其活化能接近于水中扩散的活化能。我们发现打开状态和关闭状态之间的自由能没有显着差异。激活通道打开所需的大部分多余能量用于减少打开状态的熵。这种结构重组是由 ATP 结合引发的，随后随着 CFTR-ATP-Mg 复合物进入过渡态进行水解而相互转化为开放通道结构。过渡态下 CFTR-ATP-Mg 相互作用的能量负责 CFTR 离子通道的打开，而不是 ATP 水解的能量，通道关闭是一个扩散限制过程，不需要额外的 ATP 结合。 (C) 1998 年欧洲生化学会联合会。
Single channel currents of wild-type CFTR reconstituted in lipid bilayers were recorded to study the temperature dependence of channel gating between +20 degrees C and +40 degrees C. The opening of the channel was highly temperature dependent and required an activation energy of about 100 kJ/mol. Closing of the channel was only weakly temperature dependent with an activation energy close to that of diffusion in water. We found no significant difference in the free energy between the open and closed states. Most of the excess energy needed to activate channel opening is used to diminish the entropy of the open state. This structural reorganization is initiated by ATP binding followed by interconversion to the open channel structure as the CFTR-ATP-Mg complex passes to the transition state for hydrolysis. The energy of the CFTR-ATP-Mg interaction in the transition state is responsible for the CFTR ion channel opening rather than the energy of ATP hydrolysis, Channel closing is a diffusion limited process and does not require additional ATP binding. (C) 1998 Federation of European Biochemical Societies.