Differential binding of monovalent cations to KcsA: Deciphering the mechanisms of potassium channel selectivity.
Differential binding of monovalent cations to KcsA: Deciphering the mechanisms of potassium channel selectivity.
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单价阳离子与 KcsA 的差异结合：破译钾通道选择性的机制。
DOI：
10.1016/j.bbamem.2017.01.014
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
J. González
中科院分区：
文献类型：
--
作者：
E. Montoya;M. Lourdes Renart;A. Marcela Giudici;J. A. Poveda;A. Fernández;A. Morales;J. González
这项工作探索了是否可以根据离子结合特性来解释模型钾通道KCSA的离子选择性和渗透特性。非预想的Na+或Li+以低亲和力(毫摩尔Kd‘s)结合到KCSA晶体结构中选择性滤光片上的S1和S4位贡献的一组位置上。相反，随着浓度的增加，预指K+、Rb+、Tl+甚至Cs+结合到两组不同的位置，这与预指物种能够在通道选择性过滤器的构象状态(非导电和导电)之间诱导浓度依赖的转变的结晶学证据一致。第一组这样的位置，也被分配到结晶学上的S1和S4位置，对所有意向物种(微摩尔Kd‘s)显示出类似的高亲和力，从而确保潜在竞争的非意向阳离子的位移。第二组位置，只有在过渡到导电滤光片构象时才能获得，表现出低亲和力(毫米级Kd‘s)，因此有利于阳离子的解离和渗透，这是所有S1到S4结晶学位置的结果。相反，在渗透特征中观察到的复杂性不能仅仅从结合的角度来解释，并且可能与所报道的由有意的阳离子占据S2和S3位置的差异有关。
This work explores whether the ion selectivity and permeation properties of a model potassium channel, KcsA, could be explained based on ion binding features. Non-permeant Na+or Li+bind with low affinity (millimolar KD's) to a single set of sites contributed by the S1 and S4 sites seen at the selectivity filter in the KcsA crystal structure. Conversely, permeant K+, Rb+, Tl+and even Cs+bind to two different sets of sites as their concentration increases, consistent with crystallographic evidence on the ability of permeant species to induce concentration-dependent transitions between conformational states (non-conductive and conductive) of the channel's selectivity filter. The first set of such sites, assigned also to the crystallographic S1 and S4 sites, shows similarly high affinities for all permeant species (micromolar KD's), thus, securing displacement of potentially competing non-permeant cations. The second set of sites, available only to permeant cations upon the transition to the conductive filter conformation, shows low affinity (millimolar KD's), thus, favoring cation dissociation and permeation and results from the contribution of all S1 through S4 crystallographic sites.The differences in affinities between permeant and non-permeant cations and the similarities in binding behavior within each of these two groups, correlate fully with their permeabilities relative to K+, suggesting that binding is an important determinant of the channel's ion selectivity. Conversely, the complexity observed in permeation features cannot be explained just in terms of binding and likely relates to reported differences in the occupancy of the S2 and S3 sites by the permeant cations.
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影响因子：
2.9
作者：
Heginbotham, L;Odessey, E;Miller, C
通讯作者：
Miller, C
影响因子：
9.8
作者：
Lockless SW;Zhou M;MacKinnon R
通讯作者：
MacKinnon R
通过亲和开关选择性滤光片进行 K 通道门控。
DOI：
10.1073/pnas.0308743101
发表时间：
2004
影响因子：
11.1
作者：
VanDongen,AntoniusMJ
通讯作者：
VanDongen,AntoniusMJ
DOI：
10.1085/jgp.118.3.303
发表时间：
2001-09
期刊：
The Journal of general physiology
影响因子：
--
作者：
LeMasurier M;Heginbotham L;Miller C
通讯作者：
Miller C
浅青紫链霉菌钾通道 KcsA 受钾电化学梯度调节。
DOI：
10.1016/j.bbrc.2004.02.069
发表时间：
2004
期刊：
Biochemical and biophysical research communications.
影响因子：
--
作者：
Zakharian,E;Reusch,RN
通讯作者：
Reusch,RN