Mobility and location of anesthetics in lipid bilayer membranes by high-resolution, high-field-gradient NMR

Okamura, Emiko; Nakahara, Masaru

doi:10.1016/j.ics.2005.07.041

Cited by 4 publications

(4 citation statements)

References 6 publications

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“…Since Prodan is a polarity-sensitive fluorescent probe, the λ max values depend primarily on the dielectric constant of a solvent around the probe molecules at constant temperature and pressure despite that other factors, such as a change in microviscosity around the probe molecules, are known to affect the Prodan fluorescence spectra. The local dielectric constant or the water density along a lipid molecule in the bilayer decreases monotonously from the bilayer surface to the bilayer core, which has been demonstrated as the zone model. , A higher value of λ max indicates that the probes exist in a polar or hydrophilic environment, while a lower value of λ max signifies that the probes exist in a less polar or hydrophobic environment. Therefore, the location of the Prodan molecules in the bilayer membrane of each phase can be reasonably estimated from the λ max values as a less polar region around glycerol backbone for the gel phase (i.e., ca.…”

Section: Resultsmentioning

confidence: 93%

Effect of Vesicle Size on the Prodan Fluorescence in Diheptadecanoylphosphatidylcholine Bilayer Membrane under Atmospheric and High Pressures

Goto

Sawaguchi²,

Tamai³

et al. 2010

Langmuir

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The bilayer phase behavior of diheptadecanoylphosphatidylcholine (C17PC) with different vesicle sizes (large multilamellar vesicle (LMV) and giant multilamellar vesicle (GMV)) was investigated by fluorescence spectroscopy using a polarity-sensitive fluorescent probe Prodan under atmospheric and high pressures. The difference in phase transitions and thermodynamic quantities of the transition was hardly observed between LMV and GMV used here. On the contrary, the Prodan fluorescence in the bilayer membranes changed depending on the size of vesicles as well as on the phase states. From the second derivative of fluorescence spectra, the three-dimensional image plots in which we can see the location of Prodan in the bilayer membrane as blue valleys were constructed for LMV and GMV under atmospheric pressure. The following characteristic behavior was found: (1) the Prodan molecules in GMV can be distributed to not only adjacent glycerol backbone region, but also near bulk-water region in the lamellar gel or ripple gel phase; (2) the blue valleys of GMV became deeper than those of LMV because of the greater surface density of the Prodan molecules per unit area of GMV than LMV; (3) the liquid crystalline phase of the bilayer excludes the Prodan molecules to a more hydrophilic region at the membrane surface with an increase in vesicle size; (4) the accurate information as to the phase transitions is gradually lost with increasing vesicle size. Under the high-pressure condition, the difference in Prodan fluorescence between LMV and GMV was essentially the same as the difference under atmospheric pressure except for the existence of the pressure-induced interdigitated gel phase. Further, we found that Prodan fluorescence spectra in the interdigitated gel phase were especially affected by the size of vesicles. This study revealed that the Prodan molecules can move around the headgroup region by responding not only to the phase state but also to the vesicle size, and they become a useful membrane probe, detecting important membrane properties such as the packing stress.

show abstract

Section: Resultsmentioning

confidence: 93%

Effect of Vesicle Size on the Prodan Fluorescence in Diheptadecanoylphosphatidylcholine Bilayer Membrane under Atmospheric and High Pressures

Goto

Sawaguchi²,

Tamai³

et al. 2010

Langmuir

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show abstract

“…430, 480, and 500 nm, respectively. ,, This is because the λ max value of Prodan varies with a local dielectric constant of a solvent around the Prodan molecule. The local dielectric constant or the water density along a lipid molecule in the bilayer is represented by a zone model . A higher value of λ max indicates that the probes exist in a polar environment, whereas a lower value of λ max does that they exist in a less polar environment.…”

Section: Resultsmentioning

confidence: 99%

“…The local dielectric constant or the water density along a lipid molecule in the bilayer is represented by a zone model. 22 A higher value of λ max indicates that the probes exist in a polar environment, whereas a lower value of λ max does that they exist in a less polar environment. Therefore, the location of the Prodan molecules in each phase of the PC bilayer can be estimated from the λ max values: they reside in a less polar region around the glycerol backbone when the bilayer is in the gel (L β ′ or P β ′) phase, in an intermediate region around phosphate group for the L α phase, and in a hydrophilic region around lipid headgroup for the nonbilayer gel (L β I) phase.…”

Section: Methodsmentioning

confidence: 99%

Study on the Subgel-Phase Formation Using an Asymmetric Phospholipid Bilayer Membrane by High-Pressure Fluorometry

et al. 2012

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The myristoylpalmitoylphosphatidylcholine (MPPC) bilayer membrane shows a complicated temperature-pressure phase diagram. The large portion of the lamellar gel (L(β)'), ripple gel (P(β)'), and pressure-induced gel (L(β)I) phases exist as metastable phases due to the extremely stable subgel (L(c)) phase. The stable L(c) phase enables us to examine the properties of the L(c) phase. The phases of the MPPC bilayers under atmospheric and high pressures were studied by small-angle neutron scattering (SANS) and fluorescence spectroscopy using a polarity-sensitive fluorescent probe Prodan. The SANS measurements clearly demonstrated the existence of the metastable L(β)I phase with the smallest lamellar repeat distance. From a second-derivative analysis of the fluorescence data, the line shape for the L(c) phase under high pressure was characterized by a broad peak with a minimum of ca. 460 nm. The line shapes and the minimum intensity wavelength (λ″(min)) values changed with pressure, indicating that the L(c) phase has highly pressure-sensible structure. The λ″(min) values of the L(c) phase spectra were split into ca. 430 and 500 nm in the L(β)I phase region, which corresponds to the formation of a interdigitated subgel L(c) (L(c)I) phase. Moreover, the phase transitions related to the L(c) phase were reversible transitions under high pressure. Taking into account the fluorescence behavior of Prodan for the L(c) phase, we concluded that the structure of the L(c) phase is highly probably a staggered structure, which can transform into the L(c)I phase easily.

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“…A local dielectric constant along a lipid molecule in the bilayer increases from the bilayer core to the bilayer surface, as shown by a zone model of lipid bilayers proposed by Okamura and Nakahara [27,28]. Here a higher max value means that the probes are in a polar or hydrophilic environment while a lower one does that they are in a less polar or hydrophobic environment.…”

Section: Prodan Fluorescence For Lmv Of Asymmetric Pc Bilayer Membranesmentioning

confidence: 96%

Prodan fluorescence detects the bilayer packing of asymmetric phospholipids

Goto

Matsui

Tamai

et al. 2011

Colloids and Surfaces B: Biointerfaces

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Mobility and location of anesthetics in lipid bilayer membranes by high-resolution, high-field-gradient NMR

Cited by 4 publications

References 6 publications

Effect of Vesicle Size on the Prodan Fluorescence in Diheptadecanoylphosphatidylcholine Bilayer Membrane under Atmospheric and High Pressures

Effect of Vesicle Size on the Prodan Fluorescence in Diheptadecanoylphosphatidylcholine Bilayer Membrane under Atmospheric and High Pressures

Study on the Subgel-Phase Formation Using an Asymmetric Phospholipid Bilayer Membrane by High-Pressure Fluorometry

Prodan fluorescence detects the bilayer packing of asymmetric phospholipids

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