Abstract
The effect of cholesterol on the molecular transport of an organic cation, malachite green (MG), across large unilamellar dioleolyphosphatidylglycerol (DOPG) liposome bilayers with 0-50 mol% cholesterol was studied by second harmonic generation (SHG). Because SHG is a surface-specific technique, it requires no labeled molecule, quencher, or shifting agent to distinguish the location of the solute molecules. An additional important feature of SHG is that it is sensitive only to the probe molecules bound to the liposome, whereas other methods can only differentiate between molecules that are outside and those inside the liposome. The transport kinetics of MG across the liposome bilayers was observed in real time, and the results show that cholesterol retards the rate of transport of MG across liposome bilayers. The rate was found to decrease by six times for 50 mol% cholesterol content compared with cholesterol-free liposomes. This demonstrates the applicability of SHG to investigation of the effect of liposome composition on the transport kinetics across the liposome bilayers.
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- Bittman R., Clejan S., Jain M. K., Deroo P. W., Rosenthal A. F. Effects of sterols on permeability and phase transitions of bilayers from phosphatidylcholines lacking acyl groups. Biochemistry. 1981 May 12;20(10):2790–2795. doi: 10.1021/bi00513a013. [DOI] [PubMed] [Google Scholar]
- Demel R. A., Bruckdorfer K. R., van Deenen L. L. The effect of sterol structure on the permeability of lipomes to glucose, glycerol and Rb + . Biochim Biophys Acta. 1972 Jan 17;255(1):321–330. doi: 10.1016/0005-2736(72)90031-4. [DOI] [PubMed] [Google Scholar]
- Eisenthal K. B. Liquid Interfaces Probed by Second-Harmonic and Sum-Frequency Spectroscopy. Chem Rev. 1996 Jun 20;96(4):1343–1360. doi: 10.1021/cr9502211. [DOI] [PubMed] [Google Scholar]
- Martial S., Ripoche P. An ultrarapid filtration method adapted to the measurements of water and solute permeability of synthetic and biological vesicles. Anal Biochem. 1991 Sep 2;197(2):296–304. doi: 10.1016/0003-2697(91)90395-a. [DOI] [PubMed] [Google Scholar]
- Mayer L. D., Hope M. J., Cullis P. R. Vesicles of variable sizes produced by a rapid extrusion procedure. Biochim Biophys Acta. 1986 Jun 13;858(1):161–168. doi: 10.1016/0005-2736(86)90302-0. [DOI] [PubMed] [Google Scholar]
- Mukherjee S., Chattopadhyay A. Membrane organization at low cholesterol concentrations: a study using 7-nitrobenz-2-oxa-1,3-diazol-4-yl-labeled cholesterol. Biochemistry. 1996 Jan 30;35(4):1311–1322. doi: 10.1021/bi951953q. [DOI] [PubMed] [Google Scholar]
- Robinson A. J., Richards W. G., Thomas P. J., Hann M. M. Behavior of cholesterol and its effect on head group and chain conformations in lipid bilayers: a molecular dynamics study. Biophys J. 1995 Jan;68(1):164–170. doi: 10.1016/S0006-3495(95)80171-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sankaram M. B., Thompson T. E. Interaction of cholesterol with various glycerophospholipids and sphingomyelin. Biochemistry. 1990 Nov 27;29(47):10670–10675. doi: 10.1021/bi00499a014. [DOI] [PubMed] [Google Scholar]
- Szabo G. Dual mechanism for the action of cholesterol on membrane permeability. Nature. 1974 Nov 1;252(5478):47–49. doi: 10.1038/252047a0. [DOI] [PubMed] [Google Scholar]
- Wehrli S., Ramirez C., Kraus J. L., Castaing M. Temperature-dependent effects of cholesterol on sodium transport through lipid membranes by an ionizable mobile carrier. Biochim Biophys Acta. 1992 Jun 30;1107(2):319–330. doi: 10.1016/0005-2736(92)90419-m. [DOI] [PubMed] [Google Scholar]
- Xiang T. X., Anderson B. D. Phospholipid surface density determines the partitioning and permeability of acetic acid in DMPC:cholesterol bilayers. J Membr Biol. 1995 Nov;148(2):157–167. doi: 10.1007/BF00207271. [DOI] [PubMed] [Google Scholar]
- Yeagle P. L. Cholesterol and the cell membrane. Biochim Biophys Acta. 1985 Dec 9;822(3-4):267–287. doi: 10.1016/0304-4157(85)90011-5. [DOI] [PubMed] [Google Scholar]
- Yeagle P. L., Hutton W. C., Huang C., Martin R. B. Phospholipid head-group conformations; intermolecular interactions and cholesterol effects. Biochemistry. 1977 Oct 4;16(20):4344–4349. doi: 10.1021/bi00639a003. [DOI] [PubMed] [Google Scholar]