The gating mechanism in cyclic nucleotide-gated ion channels

Sci Rep. 2018 Jan 8;8(1):45. doi: 10.1038/s41598-017-18499-0.

Abstract

Cyclic nucleotide-gated (CNG) channels mediate transduction in several sensory neurons. These channels use the free energy of CNs' binding to open the pore, a process referred to as gating. CNG channels belong to the superfamily of voltage-gated channels, where the motion of the α-helix S6 controls gating in most of its members. To date, only the open, cGMP-bound, structure of a CNG channel has been determined at atomic resolution, which is inadequate to determine the molecular events underlying gating. By using electrophysiology, site-directed mutagenesis, chemical modification, and Single Molecule Force Spectroscopy, we demonstrate that opening of CNGA1 channels is initiated by the formation of salt bridges between residues in the C-linker and S5 helix. These events trigger conformational changes of the α-helix S5, transmitted to the P-helix and leading to channel opening. Therefore, the superfamily of voltage-gated channels shares a similar molecular architecture but has evolved divergent gating mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Binding Sites
  • Cyclic Nucleotide-Gated Cation Channels / chemistry*
  • Cyclic Nucleotide-Gated Cation Channels / genetics
  • Cyclic Nucleotide-Gated Cation Channels / metabolism*
  • Ion Channel Gating*
  • Models, Molecular
  • Mutation
  • Position-Specific Scoring Matrices
  • Protein Binding
  • Protein Conformation
  • Protein Folding
  • Structure-Activity Relationship

Substances

  • Cyclic Nucleotide-Gated Cation Channels