Exposure of residues in the cyclic nucleotide-gated channel pore: P region structure and function in gating
Exposure of residues in the cyclic nucleotide-gated channel pore: P region structure and function in gating
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DOI：
10.1016/s0896-6273(00)80031-8
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发表时间：
1996-01-01
期刊：
影响因子：
16.2
通讯作者：
Siegelbaum, SA
中科院分区：
文献类型：
--
作者：
Sun, ZP;Akabas, MH;Siegelbaum, SA
在电压门控离子通道和同源环核苷酸门控（CNG）通道中，S5和S6跨膜片段（P区）之间的环被认为形成孔的衬里。为了研究牛视网膜CNG通道的P区门控的结构和作用，我们确定了11个半胱氨酸取代的P区残基的可访问性小，带电巯基试剂适用于膜补丁的内部和外部的开放和关闭状态的通道。结果表明，P区形成一个环，向通道的中心轴延伸，类似于细菌孔蛋白通道的L3环。此外，除了形成离子选择性过滤器之外，P区还用作沟道栅极，其结构在沟道打开时改变。
In voltage-gated ion channels and in the homologous cyclic nucleotide-gated (CNG) channels, the loop between the S5 and S6 transmembrane segments (P region) is thought to form the lining of the pore. To investigate the structure and the role in gating of the P region of the bovine retinal CNG channel, we determined the accessibility of 11 cysteine-substituted P region residues to small, charged sulfhydryl reagents applied to the inside and outside of membrane patches in the open and closed states of the channel. The results suggest that the P region forms a loop that extends toward the central axis of the channel, analogous to the L3 loop of bacterial porin channels. Furthermore, the P region, in addition to forming the ion selectivity filter, functions as the channel gate, the structure of which changes when the channel opens.