On the thermodynamic stability of a charged arginine side chain in a transmembrane helix.

ABSTRACT: Biological membranes consist of bilayer arrangements of lipids forming a hydrophobic core that presents a physical barrier to all polar and charged molecules. This long-held notion has recently been challenged by biological translocon-based experiments that report small apparent free energies to insert charged side chains near the center of a transmembrane (TM) helix. We have carried out fully atomistic simulations to provide the free-energy profile for moving a TM helix containing a protonated Arg side chain across a lipid bilayer. Our results reveal the fundamental thermodynamics governing the stability of charged side chains in membranes and the microscopic interactions involved. Despite local membrane deformations, where large amounts of water and lipid head groups are pulled into the

SUBMITTER: Dorairaj S 

PROVIDER: S-EPMC1829244 | biostudies-literature | 2007 Mar

REPOSITORIES: biostudies-literature