Gating at the Selectivity Filter of Ion Channels that Conduct Na+ and K+ Ions
Gating at the Selectivity Filter of Ion Channels that Conduct Na+ and K+ Ions
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DOI：
10.1016/j.bpj.2011.08.035
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发表时间：
2011-10-05
影响因子：
3.4
通讯作者：
Domene, Carmen
中科院分区：
文献类型：
--
作者：
Furini, Simone;Domene, Carmen
NaK通道是对K+和Na+具有相似渗透性的阳离子选择性通道。野生型（WT）NaK的可用晶体结构通常与沟道的导电状态相关联。在此，Na+和K+离子通过NaK的完整传导事件的平均力的势表明：i）大的能量势垒阻止离子通过WT NaK结构，ii）势垒与Asp-66和Asn-68之间氢键的存在相关，以及iii）突变以模拟环核苷酸门控通道的NaK结构传导Na+和K+。这些结果支持的假设，过滤器的阳离子选择性通道可以采用至少两种不同的结构：一个导电的，由X射线结构的NaK-CNG嵌合体，和一个封闭的，由X射线结构的WT NaK表示。
The NaK channel is a cation selective channel with similar permeability for K+ and Na+. The available crystallographic structure of wild-type (WT) NaK is usually associated with a conductive state of the channel. Here, potential of mean force for complete conduction events of Na+ and K+ ions through NaK show that: i), large energy barriers prevent the passage of ions through the WT NaK structure, ii), the barriers are correlated to the presence of a hydrogen bond between Asp-66 and Asn-68, and iii), the structure of NaK mutated to mimic cyclic nucleotide-gated channels conducts Na+ and K+. These results support the hypothesis that the filter of cation selective channels can adopt at least two different structures: a conductive one, represented by the x-ray structures of the NaK-CNG chimeras, and a closed one, represented by the x-ray structures of the WT NaK.