| 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 |
|