Comparison of DPPC and DPPG Environments in Pulmonary Surfactant Models
| Autor: | June Stewart, Michael R. Morrow, Sara Temple, Kevin M. W. Keough |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Phase transition
1 2-Dipalmitoylphosphatidylcholine Biophysics 02 engineering and technology Lamellar granule Phase Transition 03 medical and health sciences chemistry.chemical_compound Pulmonary surfactant Liquid crystal Organic chemistry Pulmonary surfactant-associated protein B 030304 developmental biology 0303 health sciences Membranes Pulmonary Surfactant-Associated Protein B Pulmonary Surfactant-Associated Protein A Bilayer Phosphatidylglycerols Atmospheric temperature range 021001 nanoscience & nanotechnology chemistry Dipalmitoylphosphatidylcholine lipids (amino acids peptides and proteins) 0210 nano-technology Protein Binding |
| Zdroj: | Biophysical Journal. 93:164-175 |
| ISSN: | 0006-3495 |
| DOI: | 10.1529/biophysj.106.102681 |
| Popis: | Deuterium nuclear magnetic resonance was used to monitor lipid acyl-chain orientational order in suspensions of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) containing Ca(2+) and the lung surfactant proteins SP-A and SP-B separately and together. To distinguish between protein-lipid interactions involving the PC and PG lipid headgroups and to examine whether such interactions might influence spatial distribution of lipids within the bilayer, acyl chains on either the DPPC or the DPPG component of the mixture were deuterated. The lipid components of the resulting mixtures were thus either DPPC-d(62)/DPPG (7:3) or DPPC/DPPG-d(62) (7:3), respectively. SP-A had little effect on DPPC-d(62) chain order but did narrow the temperature range over which DPPG-d(62) ordered at the liquid-crystal-to-gel transition. No segregation of lipid components was seen for temperatures above or below the transition. Near the transition, though, there was evidence that SP-A promoted preferential depletion of DPPG from liquid crystalline domains in the temperature range over which gel and liquid crystal domains coexist. SP-B lowered average chain order of both lipids both above and below the main transition. The perturbations of chain order by SP-A and SP-B together were smaller than by SP-B alone. This reduction in perturbation of the lipids by the additional presence of SP-A likely indicated a strong interaction between SP-A and SP-B. The competitive lipid-lipid, lipid-protein, and protein-protein interactions suggested by these observations presumably facilitate the reorganization of surfactant material inherent in the transformation from lamellar bodies to a functional surfactant layer. |
| Databáze: | OpenAIRE |
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