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Titolo:
1,2-Dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) divalent cation complexes: an X-ray scattering and freeze-fracture electron microscopy study
Autore:
Garidel, P; Forster, G; Richter, W; Kunst, BH; Rapp, G; Blume, A;
Indirizzi:
Univ Halle Wittenberg, Inst Phys Chem, D-06108 Halle, Germany Univ Halle Wittenberg Halle Germany D-06108 Chem, D-06108 Halle, Germany Univ Jena, Inst Ultrastruct Res, D-07740 Jena, Germany Univ Jena Jena Germany D-07740 st Ultrastruct Res, D-07740 Jena, Germany LUW, NL-6703 Wageningen, Netherlands LUW Wageningen Netherlands NL-6703LUW, NL-6703 Wageningen, Netherlands HASYLAB, MPI Colloid & Interface Sci, D-22603 Hamburg, Germany HASYLAB Hamburg Germany D-22603 Interface Sci, D-22603 Hamburg, Germany
Titolo Testata:
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
fascicolo: 20, volume: 2, anno: 2000,
pagine: 4537 - 4544
SICI:
1463-9076(2000)2:20<4537:1(DCC>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
CALCIUM-INDUCED FUSION; LATERAL PHASE SEPARATIONS; MEMBRANE-FUSION; PHOSPHATIDYLSERINE VESICLES; SYNCHROTRON RADIATION; DIFFRACTION ANALYSIS; MAGNETIC-RESONANCE; HYDROCARBON CHAINS; SUBGEL PHASE; LIPIDS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
58
Recensione:
Indirizzi per estratti:
Indirizzo: Blume, A Univ Halle Wittenberg, Inst Phys Chem, Muehlpforte 1, D-06108 Halle, Germany Univ Halle Wittenberg Muehlpforte 1 Halle Germany D-06108 ermany
Citazione:
P. Garidel et al., "1,2-Dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) divalent cation complexes: an X-ray scattering and freeze-fracture electron microscopy study", PHYS CHEM P, 2(20), 2000, pp. 4537-4544

Abstract

1,2-Dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) dispersed in 100 mM NaCl at pH 7 forms negatively charged multilamellar vesicles. After addition of divalent cation salts (Mg2+, Ca2+ and Sr2+) in an equimolar cation/lipidratio, a precipitate of lipid divalent cation (2:1) complexes is formed. These complexes were examined by X-ray diffraction and freeze-fracture electron microscopy to elucidate their phase structure as a function of temperature and incubation time at low temperature. The structural and morphological analysis of the DMPG divalent cation complexes stored for 7 d at 4 degrees C (initial state) revealed the formation of a lamellar phase with a very short lamellar repeat distance of 4.4-4.6 nm. The hydrocarbon chains of thelipid are packed in a subgel state. For all three complexes smooth fracture faces with crystalline appearance were observed in the electron micrographs. Increasing the temperature induces a subgel to liquid-crystalline phasetransition at around 58-62 degrees C for the Mg2+ and Sr2+ complexes and at 85 degrees C for the Ca2+ complex. The electron micrographs of the Mg2+ and Sr2+ complexes showed that in the liquid-crystalline phase regular multilamellar vesicles or large multilamellar cylinders are formed, whereas the Ca2+ complex forms lamellar structures of crystalline appearance. At lower temperature (below 35 degrees C), new phases appear: Mg2+ and Sr2+ complexes form a gel-like phase with an increased lamellar repeat distance of similar to 1 nm and a phase transition temperature of about 35 degrees C, whereas the Ca2+ complex transforms into a subgel phase which is very similar to the initial state. Our results show that the interaction of Mg2+ and Sr2+ with DMPG is very similar but different from that observed with Ca2+. The results also indicate interactions of Ca2+ with DMPG in the liquid-crystalline phase, whereas this is not observed for the other two ions.

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Documento generato il 15/01/21 alle ore 22:47:11