Gating at the Selectivity Filter of Ion Channels that Conduct Na+ and K+ Ions

被引:18
作者
Furini, Simone [1 ,2 ]
Domene, Carmen [1 ]
机构
[1] Univ Oxford, Dept Chem, Phys & Theoret Chem Lab, Oxford, England
[2] Univ Siena, Dept Med Surg & Bioengn, I-53100 Siena, Italy
基金
英国工程与自然科学研究理事会;
关键词
TETRAMERIC CATION CHANNELS; X-RAY-STRUCTURE; POTASSIUM-CHANNEL; MOLECULAR-DYNAMICS; CRYSTAL-STRUCTURE; POTENTIAL FUNCTIONS; BINDING-SITES; KCSA; MECHANISM; INACTIVATION;
D O I
10.1016/j.bpj.2011.08.035
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
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.
引用
收藏
页码:1623 / 1631
页数:9
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