Engineered high-affinity zinc binding site reveals gating configurations of a human proton channel.
Engineered high-affinity zinc binding site reveals gating configurations of a human proton channel.
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DOI：
10.1085/jgp.202012664
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发表时间：
2020-10-05
期刊：
影响因子：
--
通讯作者：
DeCoursey TE
中科院分区：
文献类型：
--
作者：
Cherny VV;Musset B;Morgan D;Thomas S;Smith SME;DeCoursey TE
电压门控质子通道（HV 1）类似于其他通道的电压传感器，但其在通道开放过程中的运动仍然存在争议。Cherny等人通过分析Zn 2+与引入的组氨酸残基的相互作用，建立了HV 1的开放和闭合门控构型。电压门控质子通道（HV 1）是一种也传导质子的电压传感器。质子穿透蛋白质的独特能力使区分封闭通道和开放通道变得复杂。当我们在hHV 1的外前庭中的位置116处用组氨酸替换缬氨酸时，在缺乏结合WT通道中的Zn 2+的两个His的构建体中，电流被外部施加的Zn 2+有力地抑制。在pH 7下，在10 nM Zn 2+下具有深远影响的高亲和力结合表明有其他基团起作用。我们假设Asp 185在我们的封闭状态模型中面对位置116，有助于Zn 2+螯合。证实了这一预测，V116 H/D185 N消除了Zn 2+结合。在C-末端截短的单体结构中研究，V116 H通道迅速激活。反常的是，Zn 2+减慢激活，产生独立于电压和Zn 2+浓度的时间常数。我们假设，在Zn 2+存在下H+电流的缓慢开启反映了Zn 2+从通道解结合的速率，类似于药物-受体解离反应。这种行为反过来表明，在hHV 1的闭合状态下，对Zn 2+的亲和力更大。支持这一假设，脉冲对揭示了一个快速的激活组件，其幅度下降后，较长的时间间隔在负电压作为封闭的通道绑定Zn 2+。开放通道中Zn 2+的较低亲和力与跨膜区域内的结构重排使Arg 205靠近位置116，静电排出Zn 2+的想法一致。这种现象提供了直接证据，表明Asp 185在封闭通道中与位置116相对，并且当通道打开时Arg 205在它们之间移动。
The voltage-gated proton channel (HV1) resembles the voltage sensors of other channels, but its movement during channel opening remains controversial. Cherny et al. establish open and closed gating configurations of HV1 by analyzing the interactions of Zn2+ with an introduced histidine residue. The voltage-gated proton channel (HV1) is a voltage sensor that also conducts protons. The singular ability of protons to penetrate proteins complicates distinguishing closed and open channels. When we replaced valine with histidine at position 116 in the external vestibule of hHV1, current was potently inhibited by externally applied Zn2+ in a construct lacking the two His that bind Zn2+ in WT channels. High-affinity binding with profound effects at 10 nM Zn2+ at pHo 7 suggests additional groups contribute. We hypothesized that Asp185, which faces position 116 in our closed-state model, contributes to Zn2+ chelation. Confirming this prediction, V116H/D185N abolished Zn2+ binding. Studied in a C-terminal truncated monomeric construct, V116H channels activated rapidly. Anomalously, Zn2+ slowed activation, producing a time constant independent of both voltage and Zn2+ concentration. We hypothesized that slow turn-on of H+ current in the presence of Zn2+ reflects the rate of Zn2+ unbinding from the channel, analogous to drug-receptor dissociation reactions. This behavior in turn suggests that the affinity for Zn2+ is greater in the closed state of hHV1. Supporting this hypothesis, pulse pairs revealed a rapid component of activation whose amplitude decreased after longer intervals at negative voltages as closed channels bound Zn2+. The lower affinity of Zn2+ in open channels is consistent with the idea that structural rearrangements within the transmembrane region bring Arg205 near position 116, electrostatically expelling Zn2+. This phenomenon provides direct evidence that Asp185 opposes position 116 in closed channels and that Arg205 moves between them when the channel opens.
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影响因子：
33.6
作者：
DeCoursey TE
通讯作者：
DeCoursey TE
DOI：
10.1111/febs.15291
发表时间：
2020-11
期刊：
The FEBS journal
影响因子：
--
作者：
Chaves G;Bungert-Plümke S;Franzen A;Mahorivska I;Musset B
通讯作者：
Musset B
影响因子：
5.5
作者：
BYERLY, L;MEECH, R;MOODY, W
通讯作者：
MOODY, W
影响因子：
5.6
作者：
Chamberlin, Adam;Qiu, Feng;Larsson, H. Peter
通讯作者：
Larsson, H. Peter
DOI：
10.1085/jgp.201511456
发表时间：
2015-11
期刊：
The Journal of general physiology
影响因子：
--
作者：
Cherny VV;Morgan D;Musset B;Chaves G;Smith SM;DeCoursey TE
通讯作者：
DeCoursey TE