Spectroscopic mapping of voltage sensor movement in the Shaker potassium channel
Spectroscopic mapping of voltage sensor movement in the Shaker potassium channel
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DOI：
10.1038/45561
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发表时间：
1999-12-16
期刊：
影响因子：
64.8
通讯作者：
Isacoff, EY
中科院分区：
文献类型：
--
作者：
Glauner, KS;Mannuzzu, LM;Isacoff, EY
电压门控离子通道是动作电位产生的基础，并触发神经分泌和肌肉收缩。这些通道由内部成孔结构域和四个电压敏感结构域组成，所述内部成孔结构域包含离子渗透途径及其门的元件，所述电压敏感结构域调节门（1-6）。为了理解电压感测的机制，有必要定义S4段的结构和运动，每个电压敏感域的响应于电压变化使带电残基移动穿过膜的部分（7-14）我们已经通过使用荧光共振能量转移作为光谱标尺（15-17）来确定Shaker K+中S4之间的距离来解决这个问题在不同的门控状态下的通道。在这里，我们提供的证据与S4是一个倾斜的螺旋，在激活过程中扭曲一致。我们建议，螺旋扭曲有助于跨膜电场的带电侧链的运动，它是参与耦合电压感应门控。
Voltage-gated ion channels underlie the generation of action potentials and trigger neurosecretion and muscle contraction. These channels consist of an inner pore-forming domain, which contains the ion permeation pathway and elements of its gates, together with four voltage-sensing domains, which regulate the gates(1-6). To understand the mechanism of voltage sensing it is necessary to define the structure and motion of the S4 segment, the portion of each voltage-sensing domain that moves charged residues across the membrane in response to voltage change(7-14) We have addressed this problem by using fluorescence resonance energy transfer as a spectroscopic ruler(15-17) to determine distances between S4s in the Shaker K+ channel in different gating states. Here we provide evidence consistent with S4 being a tilted helix that twists during activation. We propose that helical twist contributes to the movement of charged side chains across the membrane electric field and that it is involved in coupling voltage sensing to gating.