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Different Effects of Long- and Short-Chain Ceramides on the Gel-Fluid and Lamellar-Hexagonal Transitions of Phospholipids: A Calorimetric, NMR, and X-Ray Diffraction Study

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dc.creator Sot, Jesús
dc.creator Aranda, Francisco J.
dc.creator Collado, M. Isabel
dc.creator Goñi, Félix M.
dc.creator Alonso, Alicia
dc.date 2008-04-11T09:24:59Z
dc.date 2008-04-11T09:24:59Z
dc.date 2005-05
dc.date.accessioned 2017-01-31T01:01:59Z
dc.date.available 2017-01-31T01:01:59Z
dc.identifier Biophys J. 2005 May; 88(5): 3368–3380
dc.identifier 1542-0086
dc.identifier http://hdl.handle.net/10261/3539
dc.identifier 10.1529/biophysj.104.057851
dc.identifier.uri http://dspace.mediu.edu.my:8181/xmlui/handle/10261/3539
dc.description Copyright © by Biophysical Society. Final full-text version of the paper available at: http://www.biophysj.org/cgi/content/abstract/88/5/3368
dc.description The effects on dielaidoylphosphatidylethanolamine (DEPE) bilayers of ceramides containing different N-acyl chains have been studied by differential scanning calorimetry small angle x-ray diffraction and 31P-NMR spectroscopy. N-palmitoyl (Cer16), N-hexanoyl (Cer6), and N-acetyl (Cer2) sphingosines have been used. Both the gel-fluid and the lamellarinverted hexagonal transitions of DEPE have been examined in the presence of the various ceramides in the 0-25 mol % concentration range. Pure hydrated ceramides exhibit cooperative endothermic order-disorder transitions at 93 C (Cer16), 60 C (Cer6), and 54 C (Cer2). In DEPE bilayers, Cer16 does not mix with the phospholipid in the gel phase, giving rise to highmelting ceramide-rich domains. Cer16 favors the lamellar-hexagonal transition of DEPE, decreasing the transition temperature. Cer2, on the other hand, is soluble in the gel phase of DEPE, decreasing the gel-fluid and increasing the lamellar-hexagonal transition temperatures, thus effectively stabilizing the lamellar fluid phase. In addition, Cer2 was peculiar in that no equilibrium could be reached for the Cer2-DEPE mixture above 60 C, the lamellar-hexagonal transition shifting with time to temperatures beyond the instrumental range. The properties of Cer6 are intermediate between those of the other two, this ceramide decreasing both the gel-fluid and lamellar-hexagonal transition temperatures. Temperature-composition diagrams have been constructed for the mixtures of DEPE with each of the three ceramides. The different behavior of the long- and short-chain ceramides can be rationalized in terms of their different molecular geometries, Cer16 favoring negative curvature in the monolayers, thus inverted phases, and the opposite being true of the micelle-forming Cer2. These differences may be at the origin of the different physiological effects that are sometimes observed for the long- and short-chain ceramides.
dc.description This work was supported in part by grants from Ministerio de Educación y Ciencia (BCM 2002-00784) and Universidad del País Vasco (UPV 00042.310/13552). J. Sot was a predoctoral student supported by the Basque government.
dc.description Peer reviewed
dc.format 236402 bytes
dc.format application/pdf
dc.language eng
dc.publisher Biophysical Society
dc.rights openAccess
dc.title Different Effects of Long- and Short-Chain Ceramides on the Gel-Fluid and Lamellar-Hexagonal Transitions of Phospholipids: A Calorimetric, NMR, and X-Ray Diffraction Study
dc.type Artículo


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