title: A voltage-gated ion channel model inferred from the crystal structure of alamethicin at 1.5-A resolution.
abstract: The crystal structure of alamethicin in nonaqueous solvent has been determined, and refined at 1.5-A resolution. The molecular conformation of the three crystallographically independent molecules is largely alpha-helical with a bend in the helix axis at an internal proline residue. The helix structure is highly amphipathic as most of the solvent-accessible polar atoms lie on a narrow strip of surface parallel to the helix axis. Molecular models for the voltage-gated ion channel, with n-fold symmetry and based on the molecular conformations observed in the crystal, are characterized by strong surface complementarity, a hydrophilic interior and a hydrophobic exterior. The channel structures are stabilized by a hydrated annulus of hydrogen-bonded glutamine residues which produce the greatest restriction in the channel diameter.
mesh_terms: D000408:Alamethicin; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents; D003461:Crystallography; D006860:Hydrogen Bonding; D007473:Ion Channels; D046911:Macromolecular Substances; D008565:Membrane Proteins; D008958:Models, Molecular; D008961:Models, Structural; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D007473:Ion Channels; D046911:Macromolecular Substances; D008565:Membrane Proteins; D000408:Alamethicin