Effects of Lipid Membrane Curvature on Lipid Packing State Evaluated by Isothermal Titration Calorimetry

In this report, we present a novel approach for the elucidation of the physicochemical properties of lipid membranes by isothermal titration calorimetry (ITC) to quantify the heat absorbed during the solubilization of vesicles into TritonX-100 micelles. By using large and small unilamellar vesicles...

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Bibliographic Details
Published in:Langmuir 2013-01, Vol.29 (3), p.857-860
Main Authors: Yokoyama, Hirokazu, Ikeda, Keisuke, Wakabayashi, Masaki, Ishihama, Yasushi, Nakano, Minoru
Format: Article
Language:English
Subjects:
Calorimetry
Chemistry
Colloidal state and disperse state
Dimyristoylphosphatidylcholine - analogs & derivatives
Dimyristoylphosphatidylcholine - chemistry
Exact sciences and technology
General and physical chemistry
Lipids - chemistry
Membranes
Micelles
Octoxynol - chemistry
Solubility
Unilamellar Liposomes - chemistry
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Summary:In this report, we present a novel approach for the elucidation of the physicochemical properties of lipid membranes by isothermal titration calorimetry (ITC) to quantify the heat absorbed during the solubilization of vesicles into TritonX-100 micelles. By using large and small unilamellar vesicles for comparison, this method provides calorimetric data on the gel-to-liquid-crystalline phase transition and its curvature effects and, in particular, the enthalpy change upon membrane deformation from a planar to a curved shape, which cannot be obtained by the conventional approach using differential scanning calorimetry. The results showed quantitatively that the increase in membrane curvature increases the enthalpy of 1,2-dimyristoyl-sn-glycero-3-phosphocholine membranes both below and above the phase-transition temperature, and that the effect is more significant for the former condition. The calorimetric data obtained are further discussed in relation to the elastic bending energy of the membranes and membrane–peptide interaction.
ISSN:0743-7463
1520-5827
DOI:10.1021/la304532k