Structural dynamics of potassium-channel gating revealed by single-molecule FRET

Shizhen Wang, Reza Vafabakhsh, William F. Borschel, Taekjip Ha, Colin G. Nichols

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

Crystallography has provided invaluable insights regarding ion-channel selectivity and gating, but to advance understanding to a new level, dynamic views of channel structures within membranes are essential. We labeled tetrameric KirBac1.1 potassium channels with single donor and acceptor fluorophores at different sites and then examined structural dynamics within lipid membranes by single-molecule fluorescence resonance energy transfer (FRET). We found that the extracellular region is structurally rigid in both closed and open states, whereas the N-terminal slide helix undergoes marked conformational fluctuations. The cytoplasmic C-terminal domain fluctuates between two major structural states, both of which become less dynamic and move away from the pore axis and away from the membrane in closed channels. Our results reveal mobile and rigid conformations of functionally relevant KirBac1.1 channel motifs, implying similar dynamics for similar motifs in eukaryotic Kir channels and in cation channels in general.

Original languageEnglish
Pages (from-to)31-36
Number of pages6
JournalNature Structural and Molecular Biology
Volume23
Issue number1
DOIs
StatePublished - Jan 1 2016

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