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pubmed:abstractText |
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.
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