Temat: spin labeling - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Can macular xanthophylls replace cholesterol in formation of the liquid-ordered phase in lipid-bilayer membranes?
Autorzy:: Subczynski, Witold
Wisniewska-Becker, Anna
Widomska, Justyna
Powiązania:: https://bibliotekanauki.pl/articles/1039790.pdf
Data publikacji:: 2012
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: lutein
spin-labeling
zeaxanthin
liquid-ordered phase
EPR
Opis:: Lateral organization of membranes made from binary mixtures of dimyristoylphosphatidylcholine (DMPC) or dipalmitoylphosphatidylcholine (DPPC) and macular xanthophylls (lutein or zeaxanthin) was investigated using the saturation-recovery (SR) EPR spin-labeling discrimination by oxygen transport (DOT) method in which the bimolecular collision rate of molecular oxygen with the nitroxide spin label is measured. This work was undertaken to examine whether or not lutein and zeaxanthin, macular xanthophylls that parallel cholesterol in its function as a regulator of both membrane fluidity and hydrophobicity, can parallel other structural functions of cholesterol, including formation of the liquid-ordered phase in membranes. The DOT method permits discrimination of different membrane phases when the collision rates (oxygen transport parameter) differ in these phases. Additionally, membrane phases can be characterized by the oxygen transport parameter in situ without the need for separation, which provides information about the dynamics of each phase. In gel-phase membranes, two coexisting phases were discriminated in the presence of macular xanthophylls - namely, the liquid-ordered-like and solid-ordered-like phases. However, in fluid-phase membranes, xanthophylls only induce the solitary liquid-ordered-like phase, while at similar concentrations, cholesterol induces coexisting liquid-ordered and liquid-disordered phases. No significant differences between the effects of lutein and zeaxanthin were found.
Źródło:: Acta Biochimica Polonica; 2012, 59, 1; 109-114
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Attaching a spin to a protein - site-directed spin labeling in structural biology
Autorzy:: Czogalla, Aleksander
Pieciul, Aldona
Jezierski, Adam
Sikorski, Aleksander
Powiązania:: https://bibliotekanauki.pl/articles/1041067.pdf
Data publikacji:: 2007
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: protein structure
site-directed spin labeling
electron paramagnetic resonance (EPR) spectroscopy
Opis:: Site-directed spin labeling and electron paramagnetic resonance spectroscopy have recently experienced an outburst of multiple applications in protein science. Numerous interesting strategies have been introduced for determining the structure of proteins and its conformational changes at the level of the backbone fold. Moreover, considerable technical development in the field makes the technique an attractive approach for the study of structure and dynamics of membrane proteins and large biological complexes at physiological conditions. This review focuses on a brief description of site-directed spin labeling-derived techniques in the context of their recent applications.
Źródło:: Acta Biochimica Polonica; 2007, 54, 2; 235-244
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Carotenoid - membrane interactions in liposomes: effect of dipolar, monopolar, and nonpolar carotenoids
Autorzy:: Wisniewska, Anna
Widomska, Justyna
Subczynski, Witold
Powiązania:: https://bibliotekanauki.pl/articles/1041203.pdf
Data publikacji:: 2006
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: macular xanthophylls
β-cryptoxanthin
β-carotene
lutein
spin labeling
AMD
EPR
lipid bilayer
Opis:: Electron paramagnetic resonance (EPR) spin-labeling methods were used to study the effects of carotenoids on the physical properties of saturated phosphatidylcholine (PC) membranes to evaluate the contribution of the terminal hydroxyl groups of xanthophyll molecules to the carotenoid-membrane interaction. Effects of the dipolar, terminally dihydroxylated carotenoid lutein on membrane phase transition, fluidity, order, and polarity were compared with those of monopolar (β-cryptoxanthin) and nonpolar (β-carotene) carotenoids. These effects were monitored at the membrane center as a function of the amount of the carotenoid added to the sample and as a function of temperature for fluid-phase membranes. PC membranes with different thickness (from 12 to 22 carbons in alkyl chains) were used. Carotenoids shifted to lower temperatures and broadened the main phase transition of PC membranes. They decreased the membrane fluidity and increased the order of alkyl chains. Carotenoids also increased the hydrophobicity of the membrane interior. These effects were the strongest for lutein, significantly weaker for β-cryptoxanthin, and negligible for β-carotene. They decreased with the increase of the membrane thickness. Presented results suggest that anchoring of carotenoid molecules at the opposite membrane surfaces by polar hydroxyl groups is significant in enhancing their effects on membrane properties. This manuscript also shows the ability of EPR spin-labeling methods to monitor different membrane properties that can be applied in biotechnological studies with the use of liposomes.
Źródło:: Acta Biochimica Polonica; 2006, 53, 3; 475-484
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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