RRC ID 15790
Author Irie K, Kitagawa K, Nagura H, Imai T, Shimomura T, Fujiyoshi Y.
Title Comparative study of the gating motif and C-type inactivation in prokaryotic voltage-gated sodium channels.
Journal J. Biol. Chem.
Abstract Prokaryotic voltage-gated sodium channels (Na(V)s) are homotetramers and are thought to inactivate through a single mechanism, named C-type inactivation. Here we report the voltage dependence and inactivation rate of the NaChBac channel from Bacillus halodurans, the first identified prokaryotic Na(V), as well as of three new homologues cloned from Bacillus licheniformis (Na(V)BacL), Shewanella putrefaciens (Na(V)SheP), and Roseobacter denitrificans (Na(V)RosD). We found that, although activated by a lower membrane potential, Na(V)BacL inactivates as slowly as NaChBac. Na(V)SheP and Na(V)RosD inactivate faster than NaChBac. Mutational analysis of helix S6 showed that residues corresponding to the "glycine hinge" and "PXP motif" in voltage-gated potassium channels are not obligatory for channel gating in these prokaryotic Na(V)s, but mutations in the regions changed the inactivation rates. Mutation of the region corresponding to the glycine hinge in Na(V)BacL (A214G), Na(V)SheP (A216G), and NaChBac (G219A) accelerated inactivation in these channels, whereas mutation of glycine to alanine in the lower part of helix S6 in NaChBac (G229A), Na(V)BacL (G224A), and Na(V)RosD (G217A) reduced the inactivation rate. These results imply that activation gating in prokaryotic Na(V)s does not require gating motifs and that the residues of helix S6 affect C-type inactivation rates in these channels.
Volume 285(6)
Pages 3685-94
Published 2010-2-5
DOI 10.1074/jbc.M109.057455
PII M109.057455
PMID 19959480
PMC PMC2823509
MeSH Amino Acid Motifs Amino Acid Sequence Animals Bacillus / genetics Bacillus / metabolism* Bacterial Proteins / classification Bacterial Proteins / genetics Bacterial Proteins / physiology* CHO Cells Cell Line Cricetinae Cricetulus Electrophysiology Humans Ion Channel Gating / genetics Ion Channel Gating / physiology* Membrane Potentials Molecular Sequence Data Mutagenesis, Site-Directed Mutation Phylogeny Roseobacter / genetics Roseobacter / metabolism Sequence Homology, Amino Acid Shewanella putrefaciens / genetics Shewanella putrefaciens / metabolism Sodium Channels / classification Sodium Channels / genetics Sodium Channels / physiology* Transfection
IF 4.011
Times Cited 28
General Microbes JCM 2520 JCM 6121 JCM 21637