title: Orientation of lipid tubules by a magnetic field.
abstract: Lipid tubules, which are straight hollow cylinders consisting of lipid bilayers, are shown to orient in strong magnetic fields. Birefringence measurements were made of dilute samples of tubules of 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DC23PC) in magnetic fields of up to 4 T. The tubules were found to orient with their long axes parallel to the field direction, with saturated orientation [P2 (cos theta] approximately greater than 0.95) found at approximately 2 T. From known distributions of lengths and the number of bilayers in the walls, a value delta chi = (-7 +/- 1) X 10(-9) erg cm-3 G-2 was calculated for the tubules, which compares well with some previously reported values for phosphatidylcholines. Magnetic alignment will permit more sophisticated structural studies of monomeric and polymeric tubules, and provide a method of orienting macromolecules in the tubule walls or interior.
authors: Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139.
authors: C
authors: C
authors: Rosenblatt
authors: P
authors: P
authors: Yager
authors: P E
authors: PE
authors: Schoen
mesh_terms: D001718:Birefringence; D053280:Diynes; D008051:Lipid Bilayers; D008280:Magnetics; D008433:Mathematics; D008954:Models, Biological; D008968:Molecular Conformation; D010713:Phosphatidylcholines
chemical_list: D053280:Diynes; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; C053923:1,2-bis(10,12-tricosadiynoyl)phosphatidylcholine