Direct Measurement of the Effect of Cholesterol and 6-Ketocholestanol on the Membrane Dipole Electric Field Using Vibrational Stark Effect Spectroscopy Coupled with Molecular Dynamics Simulations.

ABSTRACT: Biological membranes are heterogeneous structures with complex electrostatic profiles arising from lipids, sterols, membrane proteins, and water molecules. We investigated the effect of cholesterol and its derivative 6-ketocholestanol (6-kc) on membrane electrostatics by directly measuring the dipole electric field (F⃗_d) within lipid bilayers containing cholesterol or 6-kc at concentrations of 0-40 mol% through the vibrational Stark effect (VSE). We found that adding low concentrations of cholesterol, up to ∼10 mol %, increases F⃗_d, while adding more cholesterol up to 40 mol% lowers F⃗_d. In contrast, we measured a monotonic increase in F⃗_d as 6-kc concentration increased. We propose that this membrane electric field is affected by multiple factor

SUBMITTER: Shrestha R 

PROVIDER: S-EPMC5398937 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature