Hydrogen exchange in the lipid bilayer-bound gramicidin channel

✍ Scribed by S. Huo; S. Arumugam; T.A. Cross

• Book ID: 104357811
• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 652 KB
• Volume: 7
• Category: Article
• ISSN: 0926-2040
• DOI: 10.1016/s0926-2040(96)01260-x

✦ Synopsis

Hydrogen exchange experiments for a membrane-bound polypeptide could lead to interesting functional and structural insights. Here, hydrogen/deuterium exchange, saturation transfer and differential relaxation experiments have been performed on oriented lipid bilayer-bound polypeptide samples to measure the exchange lifetimes. The polypeptide, gramicidin A, forms a monovalent cation selective channel across membranes. The pH dependent results suggest that the indole N epsilon 1-H groups show base catalyzed hydrogen exchange, but that the backbone amide sites are not base catalyzed, consistent with the exclusion of anions from this channel. Furthermore, the recently described [1] orientational distribution of the individual peptide carbonyls (i.e. carbonyls either tipped slightly in toward or away from the channel axis) is consistent with the observed difference in odd- and even-numbered amide residue exchange lifetimes.