3VOU: The Crystal Structure Of Nak-navsulp Chimera Channel

Most tetrameric channels have cytosolic domains to regulate their functions, including channel inactivation. Here we show that the cytosolic C-terminal region of NavSulP, a prokaryotic voltage-gated sodium channel cloned from Sulfitobacter pontiacus, accelerates channel inactivation. The crystal structure of the C-terminal region of NavSulP grafted into the C-terminus of a NaK channel revealed that the NavSulP C-terminal region forms a four-helix bundle. Point mutations of the residues involved in the intersubunit interactions of the four-helix bundle destabilized the tetramer of the channel and reduced the inactivation rate. The four-helix bundle was directly connected to the inner helix of the pore domain, and a mutation increasing the rigidity of the inner helix also reduced the inactivation rate. These findings suggest that the NavSulP four-helix bundle has important roles not only in stabilizing the tetramer, but also in accelerating the inactivation rate, through promotion of the conformational change of the inner helix.
PDB ID: 3VOUDownload
MMDB ID: 99204
PDB Deposition Date: 2012/2/10
Updated in MMDB: 2017/08
Experimental Method:
x-ray diffraction
Resolution: 3.2  Å
Similar Structures:
Biological Unit for 3VOU: tetrameric; determined by author and by software (PISA)
Molecular Components in 3VOU
Label Count Molecule
Proteins (4 molecules)
Ion Transport 2 Domain Protein, Voltage-gated Sodium Channel
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB