Magnetically aligned phospholipid bilayers with positive ordering: a new model membrane system.
A stable smectic phospholipid bilayer phase aligned with the director parallel to the magnetic field can be generated by the addition of certain trivalent paramagnetic lanthanide ions to a bicellar solution of dimyristoylphosphatidylcholine (DMPC) and dihexanoylphosphatidylcholine (DHPC) in water. Suitable lanthanide ions are those with positive anisotropy of their magnetic susceptibility, namely Eu3+, Er3+, Tm3+, and Yb3+. For samples doped with Tm3+, this phase extends over a wide range of Tm3+ concentrations (6-40 mM) and temperatures (35-90 degrees C) and appears to undergo a transition from a fluid nematic discotic to a fluid, but highly ordered, smectic phase at a temperature that depends on the thulium concentration. As a membrane mimetic, these new, positively ordered phospholipid phases have high potential for structural studies using a variety of techniques such as magnetic resonance (EMR and NMR), small-angle x-ray and neutron diffraction, as well as optical and infrared spectroscopy.
Prosser
R S
RS
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla 92093-0359, USA.
Hwang
J S
JS
Vold
R R
RR
D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D008280:Magnetics; D008674:Metals, Rare Earth; D008823:Micelles; D008954:Models, Biological; D008958:Models, Molecular; D008968:Molecular Conformation; D019906:Nuclear Magnetic Resonance, Biomolecular; D010742:Phospholipid Ethers / Q000737:chemistry*; D013816:Thermodynamics
C052298:1,2-dihexadecyl-sn-glycero-3-phosphocholine; D008051:Lipid Bilayers; D008674:Metals, Rare Earth; D008823:Micelles; D010742:Phospholipid Ethers; D004134:Dimyristoylphosphatidylcholine