Electrostatic interactions in gramicidin channels. Three-dielectric model.
A model based on the solution of the electrostatic potential for a geometry of three dielectric regions associated with a gramicidin A channel (GA) is presented. The model includes a cylindrical dielectric layer to represent the peptide backbone and dipole rings to account for dipolar side chains. Image potential and dipolar contributions for different orientations and positions along the channel are analyzed. The conductance of GA and two analogues obtained by substituting the amino acid at position 1 are studied. The numerical simulation reproduces experimental results (Barrett et al. 1986, Biophys J 49, 673-686) and supports the idea that electrostatic dipole-ion interactions are of primary importance in gramicidin channel function.
Martínez
G
G
Facultad de Física, Departamento de Física Aplicada III, Universidad Complutense, Madrid, Spain.
Sancho
M
M
D000595:Amino Acid Sequence; D004594:Electrophysiology; D006096:Gramicidin / Q000737:chemistry* / Q000378:metabolism; D007473:Ion Channels / Q000737:chemistry* / Q000502:physiology; D008432:Mathematical Computing; D008564:Membrane Potentials / Q000502:physiology; D008954:Models, Biological; D008969:Molecular Sequence Data
D007473:Ion Channels; D006096:Gramicidin