Korn S J, Ikeda S R
Department of Physiology and Neurobiology, University of Connecticut, Storrs 06269, USA.
Science. 1995 Jul 21;269(5222):410-2. doi: 10.1126/science.7618108.
Permeation selectivity was studied in two human potassium channels, Kv2.1 and Kv1.5, expressed in a mouse cell line. With normal concentrations of potassium and sodium, both channels were highly selective for potassium. On removal of potassium, Kv2.1 displayed a large sodium conductance that was inhibited by low concentrations of potassium. The channel showed a competition mechanism of selectivity similar to that of calcium channels. In contrast, Kv1.5 displayed a negligible sodium conductance on removal of potassium. The observation that structurally similar potassium channels show different abilities to conduct sodium provides a basis for understanding the structural determinants of potassium channel selectivity.
在小鼠细胞系中表达的两种人类钾通道Kv2.1和Kv1.5中研究了通透选择性。在正常钾和钠浓度下，两种通道对钾都具有高度选择性。去除钾后，Kv2.1表现出大量的钠电导，该电导受到低浓度钾的抑制。该通道显示出与钙通道类似的选择性竞争机制。相比之下，去除钾后，Kv1.5表现出可忽略不计的钠电导。结构相似的钾通道表现出不同的钠传导能力这一观察结果为理解钾通道选择性的结构决定因素提供了基础。
