3VOU

The crystal structure of NaK-NavSulP chimera channel

Summary for 3VOU

• Entry DOI: 10.2210/pdb3vou/pdb
• Descriptor: Ion transport 2 domain protein, Voltage-gated sodium channel, SODIUM ION, COBALT (II) ION (3 entities in total)
• Functional Keywords: 4-helical bundle, ion channel, membrane, transport protein
• Biological source: Bacillus weihenstephanensis; More
• Total number of polymer chains: 2
• Total formula weight: 33604.42

Authors

Irie, K.,Shimomura, T.,Fujiyoshi, Y. (deposition date: 2012-02-10, release date: 2012-05-02, Last modification date: 2023-11-08)

Primary citation

Irie, K.,Shimomura, T.,Fujiyoshi, Y.
The C-terminal helical bundle of the tetrameric prokaryotic sodium channel accelerates the inactivation rate
Nat Commun, 3:793-793, 2012

PubMed Abstract: 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.

PubMed: 22531178
DOI: 10.1038/ncomms1797

Experimental method

X-RAY DIFFRACTION (3.2 Å)