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Revisiting Volumes of Lipid Components in Bilayers.
Nagle, John F; Venable, Richard M; Maroclo-Kemmerling, Ezekiel; Tristram-Nagle, Stephanie; Harper, Paul E; Pastor, Richard W.
Afiliación
  • Nagle JF; Department of Physics , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States.
  • Venable RM; Laboratory of Computational Biology , National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda , Maryland 20892 , United States.
  • Maroclo-Kemmerling E; Department of Physics , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States.
  • Tristram-Nagle S; Department of Physics , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States.
  • Harper PE; Department of Physics & Astronomy , Calvin College , Grand Rapids , Michigan 49546 , United States.
  • Pastor RW; Laboratory of Computational Biology , National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda , Maryland 20892 , United States.
J Phys Chem B ; 123(12): 2697-2709, 2019 03 28.
Article en En | MEDLINE | ID: mdl-30836006
In addition to obtaining the highly precise volumes of lipids in lipid bilayers, it has been desirable to obtain the volumes of parts of each lipid, such as the methylenes and terminal methyls on the hydrocarbon chains and the head group. Obtaining such component volumes from experiment and from simulations is re-examined, first by distinguishing methods based on apparent versus partial molar volumes. Although somewhat different, both these methods give results that are counterintuitive and that differ from results obtained by a more local method that can only be applied to simulations. These comparisons reveal differences in the average methylene component volume that result in larger differences in the head group component volumes. Literature experimental volume data for unsaturated phosphocholines and for alkanes have been used and new data have been acquired for saturated phosphocholines. Data and simulations cover extended ranges of temperature to assess both the temperature and chain length dependence of the component volumes. A new method to refine the determination of component volumes is proposed that uses experimental data for different chain lengths at temperatures guided by the temperature dependence determined in simulations. These refinements enable more precise comparisons of the component volumes of different lipids and alkanes in different phases. Finally, the notion of free volume is extended to components using the Lennard-Jones radii to estimate the excluded volume of each component. This analysis reveals that head group free volumes are relatively independent of thermodynamic phase, whereas both the methylene and methyl free volumes increase dramatically when bilayers transition from gel to fluid.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Fosfatidilcolinas / Membrana Dobles de Lípidos Idioma: En Revista: J Phys Chem B Asunto de la revista: QUIMICA Año: 2019 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos
Texto completo
Añadir a Mi BVS
Imprimir
XML
PubMed Links
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Fosfatidilcolinas / Membrana Dobles de Lípidos Idioma: En Revista: J Phys Chem B Asunto de la revista: QUIMICA Año: 2019 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos