Novel chelate-induced magnetic alignment of biological membranes.
A phospholipid chelate complexed with ytterbium (DMPE-DTPA:Yb3+) is shown to be readily incorporated into a model membrane system, which may then be aligned in a magnetic field such that the average bilayer normal lies along the field. This so-called positively ordered smectic phase, whose lipids consist of less than 1% DMPE-DTPA:Yb3+, is ideally suited to structural studies of membrane proteins by solid-state NMR, low-angle diffraction, and spectroscopic techniques that require oriented samples. The chelate, 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine diethylenetriaminepentaacetic acid, which strongly binds the lanthanide ions and serves to orient the membrane in a magnetic field, prevents direct lanthanide-protein interactions and significantly reduces paramagnetic shifts and line broadening. Similar low-spin lanthanide chelates may have applications in field-ordered solution NMR studies of water-soluble proteins and in the design of new magnetically aligned liquid crystalline phases.
Prosser
R S
RS
Department of Chemistry, Kent State University, Kent, Ohio 44242, USA. sprosser@membrane.kent.edu
Volkov
V B
VB
Shiyanovskaya
I V
IV
D002614:Chelating Agents / Q000494:pharmacology*; D007811:Lanthanum / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D008565:Membrane Proteins / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D004369:Pentetic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D010714:Phosphatidylethanolamines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry
D002614:Chelating Agents; D008051:Lipid Bilayers; D008565:Membrane Proteins; D010714:Phosphatidylethanolamines; D010743:Phospholipids; C073846:ytterbium DTPA; D007811:Lanthanum; D004369:Pentetic Acid; C018525:1,2-dimyristoylphosphatidylethanolamine