Exposure of residues in the cyclic nucleotide-gated channel pore: P region structure and function in gating

Zhong Ping Sun, Myles H. Akabas, Evan H. Goulding, Arthur Karlin, Steven A. Siegelbaum

Research output: Contribution to journalArticle

102 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)141-149
Number of pages9
JournalNeuron
Volume16
Issue number1
DOIs
StatePublished - Jan 1996
Externally publishedYes

ASJC Scopus subject areas

  • Neuroscience(all)

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