Seoh S A, Sigg D, Papazian D M, Bezanilla F
Department of Physiology, School of Medicine, University of California, Los Angeles 90095-1751, USA.
Neuron. 1996 Jun;16(6):1159-67. doi: 10.1016/s0896-6273(00)80142-7.
The activation of Shaker K+ channels is steeply voltage dependent. To determine whether conserved charged amino acids in putative transmembrane segments S2, S3, and S4 contribute to the gating charge of the channel, the total gating charge movement per channel was measured in channels containing neutralization mutations. Of eight residues tested, four contributed significantly to the gating charge: E293, an acidic residue in S2, and R365, R368, and R371, three basic residues in the S4 segment. The results indicate that these residues are a major component of the voltage sensor. Furthermore, the S4 segment is not solely responsible for gating charge movement in Shaker K+ channels.
Shaker钾离子通道的激活强烈依赖于电压。为了确定假定的跨膜片段S2、S3和S4中保守的带电氨基酸是否对通道的门控电荷有贡献，在含有中和突变的通道中测量了每个通道的总门控电荷移动。在测试的八个残基中，有四个对门控电荷有显著贡献：S2中的酸性残基E293，以及S4片段中的三个碱性残基R365、R368和R371。结果表明，这些残基是电压传感器的主要组成部分。此外，S4片段并非单独负责Shaker钾离子通道中的门控电荷移动。
