Download MendeleyMicroED structure of the NaK ion channel reveals a Na+partition process into the selectivity filter.
Liu, S., Gonen, T.(2018) Commun Biol 1: 38-38
- PubMed: 30167468
- DOI: https://doi.org/10.1038/s42003-018-0040-8
- Primary Citation of Related Structures:
6CPV - PubMed Abstract:
Sodium (Na + ) is a ubiquitous and important inorganic salt mediating many critical biological processes such as neuronal excitation, signaling, and facilitation of various transporters. The hydration states of Na + are proposed to play critical roles in determining the conductance and the selectivity of Na + channels, yet they are rarely captured by conventional structural biology means. Here we use the emerging cryo-electron microscopy (cryoEM) method micro-electron diffraction (MicroED) to study the structure of a prototypical tetrameric Na + -conducting channel, NaK, to 2.5 Å resolution from nano-crystals. Two new conformations at the external site of NaK are identified, allowing us to visualize a partially hydrated Na + ion at the entrance of the channel pore. A process of dilation coupled with Na + movement is identified leading to valuable insights into the mechanism of ion conduction and gating. This study lays the ground work for future studies using MicroED in membrane protein biophysics.
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA, 20147, USA.
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