期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2008
卷号：105
期号：9
页码：3310-3314
DOI：10.1073/pnas.0709809105
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：By opening and closing the permeation pathway (gating) in response to cGMP binding, cyclic nucleotide-gated (CNG) channels serve key roles in the transduction of visual and olfactory signals. Compiling evidence suggests that the activation gate in CNG channels is not located at the intracellular end of pore, as it has been established for voltage-activated potassium (KV) channels. Here, we show that ion permeation in CNG channels is tightly regulated at the selectivity filter. By scanning the entire selectivity filter using small cysteine reagents, like cadmium and silver, we observed a state-dependent accessibility pattern consistent with gated access at the middle of the selectivity filter, likely at the corresponding position known to regulate structural changes in KcsA channels in response to low concentrations of permeant ions.
