Is arginine charged in a membrane?

Printer-friendly versionPrinter-friendly versionPDF versionPDF version
TitleIs arginine charged in a membrane?
Publication TypeJournal Article
Year of Publication2008
AuthorsLi, L, Vorobyov, I, Mackerell, AD, Allen, TW
JournalBiophys J
Volume94
Issue2
PaginationL11-3
Date Published2008 Jan 15
ISSN1542-0086
KeywordsArginine, Lipid Bilayers, Proton-Motive Force, Thermodynamics
Abstract

"Charged" amino acids play countless important roles in protein structure and function. Yet when these side chains come into contact with membranes we do not fully understand their behavior. This is highlighted by a recent model of voltage-gated ion channel activity and translocon-based experiments that suggest small penalties to expose these side chains to lipids, opposing the prevailing view in membrane biophysics. Here we employ a side chain analog as well as a transmembrane helix model to determine the free energy as a function of protonation state and position for a lipid-exposed arginine (Arg) residue across a membrane. We observe high free energy barriers for both the charged and neutral states. Due to the stabilizing influence of membrane deformations for the protonated form, the Arg side chain experiences a pK(a) shift of

DOI10.1529/biophysj.107.121566
Alternate JournalBiophys. J.
PubMed ID17981901
PubMed Central IDPMC2157258
Grant ListGM50501 / GM / NIGMS NIH HHS / United States