ROLE OF SURFACE ELECTROSTATICS IN THE OPERATION OF A HIGH-CONDUCTANCE CA-2+-ACTIVATED K+ CHANNEL
ROLE OF SURFACE ELECTROSTATICS IN THE OPERATION OF A HIGH-CONDUCTANCE CA-2+-ACTIVATED K+ CHANNEL
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DOI：
10.1021/bi00446a020
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发表时间：
1989-10-03
期刊：
影响因子：
2.9
通讯作者：
MILLER, C
中科院分区：
文献类型：
--
作者：
MACKINNON, R;LATORRE, R;MILLER, C
本文表明，局部电场来源于带负电荷的基团上的K+特异性离子通道修改其行为。单一的高电导，钙激活的K+通道在中性磷脂双层进行了研究。通道蛋白表面电荷的实验操纵羧基酯化使用三甲基氧鎓（TMO）或电解质筛选。离子传导、离子阻断和电压依赖性门控三种通道特性受表面静电的影响。负电荷通过在孔入口处建立局部负电位来增加阳离子孔阻断剂的亲和力;这些电荷通过在离子通道上建立电位梯度来改变通道门控;最后，这两种效应都影响离子通过孔的渗透。
This paper demonstrates that local electric fields originating from negatively charged groups on a K+-specific ion channel modify its behavior. Single high-conductance, Ca2+-activated K+ channels were studied in neutral phospholipid bilayers. The channel protein surface charges were manipulated experimentally by carboxyl group esterification using trimethyloxonium (TMO) or by electrolyte screening. Three channel properties-ion conduction, ion blockade, and voltage-dependent gating-are affected by surface electrostatics. Negative charges increase the affinity of cationic pore blockers by establishing a local negative potential at the pore entrance; these charges modify channel gating by establishing a potential gradient across the ion channel; finally, both effects influence ion permeation through the pore.