Normal vibrations of ternary DOPC/DPPC/cholesterol lipid bilayers by low-frequency Raman spectroscopy.
| Autor: | Leonov DV; Department of Physics, Novosibirsk State University Novosibirsk 630090 Russia dzuba@kinetics.nsc.ru., Dzuba SA; Department of Physics, Novosibirsk State University Novosibirsk 630090 Russia dzuba@kinetics.nsc.ru.; Voevodsky Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences Novosibirsk 630090 Russia., Surovtsev NV; Department of Physics, Novosibirsk State University Novosibirsk 630090 Russia dzuba@kinetics.nsc.ru.; Institute of Automation and Electrometry, Russian Academy of Sciences Novosibirsk 630090 Russia. |
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| Jazyk: | angličtina |
| Zdroj: | RSC advances [RSC Adv] 2019 Oct 25; Vol. 9 (59), pp. 34451-34456. Date of Electronic Publication: 2019 Oct 25 (Print Publication: 2019). |
| DOI: | 10.1039/c9ra06114b |
| Abstrakt: | A lipid bilayer containing a ternary mixture of low- and high-melting lipids and cholesterol (Chol) can give rise to domain formation, referred to as lipid rafts. Low-frequency Raman spectroscopy at reduced temperatures allows detection of normal membrane mechanical vibrations. In this work, Raman spectra were obtained in the spectral range between 5 and 90 cm -1 for bilayers prepared from dioleoyl- glycero -phosphocholine (DOPC), dipalmitoyl- glycero -phosphocholine (DPPC) and Chol. A narrow peak detected between 13 and 16 cm -1 was attributed to the vibrational eigenmode of a lipid monolayer (a leaflet). For the equimolar DOPC/DPPC ratio, the Chol concentration dependence for the peak position, width and amplitude may be divided into three distinct ranges: below 9 mol%, the intermediate range between 9 mol% and 38 mol%, and above 38 mol%. In the intermediate range the peak position attains its minimum, and the peak width drops approximately by a factor of two as compared with the Chol-free bilayers. Meanwhile, this range is known for raft formation in a fluid state. The obtained results may be interpreted as evidence that bilayer structures in the raft-containing fluid state may be frozen at low temperatures. The drop of peak width indicates that at the spatial scale of the experiment (∼2.5 nm) the intermolecular bilayer structure with raft formation becomes more homogeneous and more cohesive. Competing Interests: There are no conflicts to declare. (This journal is © The Royal Society of Chemistry.) |
| Databáze: | MEDLINE |
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