Publication Date
2018
Journal or Book Title
Nature Communications
Abstract
The gating mechanism of transmembrane ion channels is crucial for understanding how these proteins control ion flow across membranes in various physiological processes. Big potassium (BK) channels are particularly interesting with large single-channel conductance and dual regulation by membrane voltage and intracellular Ca2+. Recent atomistic structures of BK channels failed to identify structural features that could physically block the ion flow in the closed state. Here, we show that gating of BK channels does not seem to require a physical gate. Instead, changes in the pore shape and surface hydrophobicity in the Ca2+-free state allow the channel to readily undergo hydrophobic dewetting transitions, giving rise to a large free energy barrier for K+permeation. Importantly, the dry pore remains physically open and is readily accessible to quaternary ammonium channel blockers. The hydrophobic gating mechanism is also consistent with scanning mutagenesis studies showing that modulation of pore hydrophobicity is correlated with activation properties.
ORCID
http://orcid.org/0000-0002-5281-1150
DOI
https://doi.org/10.1038/s41467-018-05970-3
Volume
9
License
UMass Amherst Open Access Policy
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Jia, Zhiguang; Yazdani, Mahdieh; Zhang, Guohui; Cui, Jianmin; and Chen, Jianhan, "Hydrophobic gating in BK channels" (2018). Nature Communications. 1451.
https://doi.org/10.1038/s41467-018-05970-3