title: Infrared spectra of the Gramicidin A transmembrane channel: the single-stranded-beta 6-helix.
abstract: IR spectra are reported for preparations of Gramicidin A and malonyl Gramicidin A incorporated as the channel state in phospholipid structures. In this preparation Gramicidin A has already been shown to be unequivocally in the single-stranded beta-helical conformation. The result is an amide I frequency of 1633 +/- 1 cm-1. This demonstrates that the single-stranded beta-helix has an amide I frequency that has previously been considered to be diagnostic of antiparallel double-stranded beta-helix and of beta-sheet structures.
mesh_terms: D006096:Gramicidin / Q000031:analogs & derivatives; D007473:Ion Channels / Q000378:metabolism; D008051:Lipid Bilayers; D008244:Lysophosphatidylcholines; D008954:Models, Biological; D008958:Models, Molecular; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared
chemical_list: D007473:Ion Channels; D008051:Lipid Bilayers; D008244:Lysophosphatidylcholines; D006096:Gramicidin; C025990:malonyl gramicidin