Thermal phase behavior of DMPG bilayers in aqueous dispersions as revealed by 2H- and 31P-NMR
The synthetic lipid 1,2-dimyristoyl-sn-3-phosphoglycerol (DMPG), when dispersed in water/NaCl exhibits a complex phase behavior caused by its almost unlimited swelling in excess water. Using deuterium ((2)H)- and phosphorus ((31)P)-NMR we have studied the molecular properties of DMPG/water/NaCl disp...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1999. - 27(2011), 16 vom: 16. Aug., Seite 10041-9 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2011
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Lipid Bilayers Phosphatidylglycerols Phosphorus 27YLU75U4W Deuterium AR09D82C7G dimyristoylphosphatidylglycerol BI71WT9P3R |
| Zusammenfassung: | The synthetic lipid 1,2-dimyristoyl-sn-3-phosphoglycerol (DMPG), when dispersed in water/NaCl exhibits a complex phase behavior caused by its almost unlimited swelling in excess water. Using deuterium ((2)H)- and phosphorus ((31)P)-NMR we have studied the molecular properties of DMPG/water/NaCl dispersions as a function of lipid and NaCl concentration. We have measured the order profile of the hydrophobic part of the lipid bilayer with deuterated DMPG while the orientation of the phosphoglycerol headgroup was deduced from the (31)P NMR chemical shielding anisotropy. At temperatures >30 °C we observe well-resolved (2)H- and (31)P NMR spectra not much different from other liquid crystalline bilayers. From the order profiles it is possible to deduce the average length of the flexible fatty acyl chain. Unusual spectra are obtained in the temperature interval of 20-25 °C, indicating one or several phase transitions. The most dramatic changes are seen at low lipid concentration and low ionic strength. Under these conditions and at 25 °C, the phosphoglycerol headgroup rotates into the hydrocarbon layer and the hydrocarbon chains show larger flexing motions than at higher temperatures. The orientation of the phosphoglycerol headgroup depends on the bilayer surface charge and correlates with the degree of dissociation of DMPG-Na(+). The larger the negative surface charge, the more the headgroup rotates toward the nonpolar region |
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| Beschreibung: | Date Completed 09.01.2012 Date Revised 21.11.2013 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1520-5827 |
| DOI: | 10.1021/la201027p |