5IWO: Bacterial Sodium Channel Pore Domain, Low Bromide

Voltage-gated ion channels (VGICs) are outfitted with diverse cytoplasmic domains that impact function. To examine how such elements may affect VGIC behavior, we addressed how the bacterial voltage-gated sodium channel (BacNaV) C-terminal cytoplasmic domain (CTD) affects function. Our studies show that the BacNaV CTD exerts a profound influence on gating through a temperature-dependent unfolding transition in a discrete cytoplasmic domain, the neck domain, proximal to the pore. Structural and functional studies establish that the BacNaV CTD comprises a bi-partite four-helix bundle that bears an unusual hydrophilic core whose integrity is central to the unfolding mechanism and that couples directly to the channel activation gate. Together, our findings define a general principle for how the widespread four-helix bundle cytoplasmic domain architecture can control VGIC responses, uncover a mechanism underlying the diverse BacNaV voltage dependencies, and demonstrate that a discrete domain can encode the temperature-dependent response of a channel.
PDB ID: 5IWODownload
MMDB ID: 138006
PDB Deposition Date: 2016/3/22
Updated in MMDB: 2016/04
Experimental Method:
x-ray diffraction
Resolution: 3.33  Å
Source Organism:
Similar Structures:
Biological Unit for 5IWO: tetrameric; determined by author and by software (PISA)
Molecular Components in 5IWO
Label Count Molecule
Proteins (4 molecules)
Ion Transport Protein
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

Citing MMDB