The gramicidin pore: crystal structure of a cesium complex.
Gramicidin, a linear polypeptide composed of hydrophobic amino acids with alternating L- and D- configurations, forms transmembrane ion channels. The crystal structure of a gramicidin-cesium complex has been determined at 2.0 angstrom resolution. In this structure, gramicidin forms a 26 angstrom long tube comprised of two polypeptide chains arranged as antiparallel beta strands that are wrapped into a left-handed helical coil with 6.4 residues per turn. The polypeptide backbone forms the interior of the hydrophilic, solvent-filled pore and the side chains form a hydrophobic and relatively regular surface on the outside of the pore. This example of a crystal structure of a solvent-filled ion pore provides a basis for understanding the physical nature of ion translocation.
Wallace
B A
BA
Department of Chemistry and Center for Biophysics, Rensselaer Polytechnic Institute, Troy, NY 12180.
Ravikumar
K
K
D001665:Binding Sites; D002586:Cesium; D003198:Computer Simulation; D003461:Crystallography; D006096:Gramicidin; D007473:Ion Channels; D008024:Ligands; D046911:Macromolecular Substances; D008565:Membrane Proteins; D008958:Models, Molecular; D011487:Protein Conformation
D007473:Ion Channels; D008024:Ligands; D046911:Macromolecular Substances; D008565:Membrane Proteins; D006096:Gramicidin; D002586:Cesium