1c4d

Publication Abstract from PubMed

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.

The gramicidin pore: crystal structure of a cesium complex.,Wallace BA, Ravikumar K Science. 1988 Jul 8;241(4862):182-7. PMID:2455344^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.