Membrane water-penetration profiles from spin labels

  title={Membrane water-penetration profiles from spin labels},
  author={Derek Marsh},
  journal={European Biophysics Journal},
  • D. Marsh
  • Published 1 December 2002
  • Physics, Chemistry
  • European Biophysics Journal
Abstract. Spin label hyperfine splittings in mixtures of protic and aprotic solvents are used to obtain association constants KA,h for hydrogen bonding to oxazolidine nitroxides. With the Onsager approach to account for the variation in local dielectric constant, these results are used to determine the effective penetration profile of water into fluid phospholipid membranes, from recent electron paramagnetic resonance (EPR) studies on phospholipids spin-labelled systematically down the sn-2… 

Spin-Label EPR for Determining Polarity and Proticity in Biomolecular Assemblies: Transmembrane Profiles

  • D. Marsh
  • Chemistry, Physics
    Applied magnetic resonance
  • 2010
Applications to studies of the transverse polarity profiles in lipid bilayers, which constitute the permeability barrier of biological membranes, are reviewed and emphasis is given to parallels with the permeation profiles of oxygen and nitric oxide that are determined by using nonlinear continuous-wave EPR and saturation recovery EPR.

Intramembrane polarity by electron spin echo spectroscopy of labeled lipids.

Membrane curvature and cholesterol effects on lipids packing and spin-labelled lipids conformational distributions

The results show that in curved vesicles lacking cholesterol, the label attached to carbon 16 may travel as far high along the membrane normal as the location of the label on carbon 5, due to the presence of U-shaped lipid conformations.

Conformational distributions and hydrogen bonding in gel and frozen lipid bilayers: a high frequency spin-label ESR study.

The ESR parameters of PC spin labels in frozen membranes do not simply represent the membrane polarity or water penetration profile. Instead, they show a distribution between hydrogen-bonded (HB) and

Librational motion of spin-labeled lipids in high-cholesterol containing membranes from echo-detected EPR spectra.

Two-pulse, echo-detected electron paramagnetic resonance (EPR) spectroscopy was used to study the librational motions of spin-labeled lipids in membranes of dipalmitoylphosphatidylcholine + 50 mol % cholesterol, which are important for glass-like states and are generally relevant to high lipid packing densities, e.g., in cholesterol-containing raft domains and condensed complexes.

Using spin polarised positive muons for studying guest molecule partitioning in soft matter structures.

The experimental technique which permits highly sensitive spectroscopy as previously demonstrated for surfactant mixtures is described and its capability in the study of partitioning of cosurfactant molecules in surfactants bilayers is demonstrated in order to elucidate the main factors which contribute to cosurFactant ordering at interfaces.



Polarity contributions to hyperfine splittings of hydrogen-bonded nitroxides--the microenvironment of spin labels.

  • D. Marsh
  • Chemistry
    Journal of magnetic resonance
  • 2002
A self-consistent treatment of reaction field effects on isotropic (14)N hyperfine coupling constants of nitroxide spin labels in mixtures of polar and apolar solvents is given based on the Onsager

Polarity and permeation profiles in lipid membranes

  • D. Marsh
  • Materials Science
    Proceedings of the National Academy of Sciences of the United States of America
  • 2001
The results are relevant not only to the permeation of water and polar solutes into membranes and their permeabilities, but also to depth determinations of site-specifically spin-labeled protein residues by using paramagnetic relaxation agents.

Electric Moments of Molecules in Liquids