Comparison of cholesterol and its direct precursors along the biosynthetic pathway: Effects of cholesterol, desmosterol and 7-dehydrocholesterol on saturated and unsaturated lipid bilayers

2008 ◽  
Vol 129 (15) ◽  
pp. 154508 ◽  
Author(s):  
Tomasz Róg ◽  
Ilpo Vattulainen ◽  
Maurice Jansen ◽  
Elina Ikonen ◽  
Mikko Karttunen
Keyword(s):  
Lipid Bilayers ◽  
Biosynthetic Pathway ◽  
Unsaturated Lipid

Selective arrangement of vesicles on artificial lipid membrane by biotin-avidin interaction

2021 ◽  
Author(s):  
Kai Hashino ◽  
Daiya Mombayashi ◽  
Yuto Nakatani ◽  
Azusa Oshima ◽  
Masumi Yamaguchi ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Liquid Crystalline ◽  
Lipid Membrane ◽  
Unsaturated Lipid ◽  
Si Substrates ◽  
Phase Domain ◽  
Unsaturated Lipids ◽  
Lipid Mixtures ◽  
The Difference

Abstract Lipid bilayers suspended over microwells on Si substrates are promising platforms for nanobiodevices that mimic cell membranes. Using the biotin-avidin interaction, we have succeeded in selectively arranging vesicles on the freestanding region of a lipid bilayer. When ternary lipid mixtures of saturated lipid, unsaturated lipid, and cholesterol are used, they separate into liquid-order (Lo) and liquid-crystalline (Lα) domains. A freestanding lipid bilayer prefers the Lα-phase over the Lo-phase because of the difference in their flexibility. In addition, the type of biotinylated lipid determines whether it is localized in the Lα-phase domain or the Lo-phase domain. As a result, the biotinylated unsaturated lipids localized in the Lα-phase domain aggregate in the freestanding lipid bilayer, and vesicles labeled with biotin selectively bind to the freestanding lipid bilayer by the biotin-avidin interaction. This technique helps to introduce biomolecules into the freestanding lipid bilayer of nanobiodevices via vesicles.

scholarly journals Cholesterol Effect on the Elastic Properties of Unsaturated Lipid Bilayers

2016 ◽  
Vol 110 (3) ◽  
pp. 369a-370a
Author(s):  
Pavel Bashkirov ◽  
Ksenia Chekashkina ◽  
Ariana Velasco del Olmo ◽  
Piotr Kuzmin ◽  
Anna Shnyrova ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Elastic Properties ◽  
Unsaturated Lipid

Unsaturated lipid bilayers at cryogenic temperature: librational dynamics of chain-labeled lipids from pulsed and CW-EPR

2019 ◽  
Vol 21 (34) ◽  
pp. 18699-18705 ◽  
Author(s):  
Erika Aloi ◽  
Rita Guzzi ◽  
Rosa Bartucci
Keyword(s):  
Low Temperature ◽  
Lipid Bilayers ◽  
Cryogenic Temperature ◽  
Acyl Chain ◽  
Epr Spectra ◽  
Unsaturated Lipid ◽  
Librational Motion

Echo-detected EPR spectra are used to study the effects of acyl chain unsaturation on the librational motion of chain-labeled lipids in the low-temperature phases of POPC and DOPC bilayers.

Chlorophyll and photosynthesis

1976 ◽  
Vol 273 (924) ◽  
pp. 287-294 ◽  
Keyword(s):  
Lipid Bilayers ◽  
Evolutionary History ◽  
Biosynthetic Pathway ◽  
Closed Shell ◽  
Reducing Atmosphere ◽  
History Of ◽  
History Of Photosynthesis ◽  
Aqueous Conditions ◽  
Life On Earth ◽  
Modern Era

Photosynthesis is the prerequisite of all life on earth. Chlorophyll fulfils the requirements for photosynthesis: the absorption of visible light, the photochemical capabilities, a rich supply of redox levels and chemical stability. The biosynthetic pathway of chlorophyll can be read as the evolutionary history of photosynthesis. Our exegesis is that the primary porphyrins served for early photosynthesis. The porphyrins readily photo-oxidize organic compounds under the reducing, aqueous conditions of this early era. The formation of oxidized substances in a reducing atmosphere supplied the thermodynamic gradient necessary for organized life processes. Conversely, the closed-shell metalloporphyrins, notable magnesium porphyrins, are powerful photoreducing agents. When coupled to the ultimate electron source, water, oxygen was produced and the modern era of photosynthesis was born. At the same time, the efficiency and usefulness of the photopigments was increased by incorporating them into the organized cellular system of membranes. The clear gradient of ionic to hydrophophic structures along the biosynthetic pathway from porphyrins to chlorophyll supports this view. Experimental evidence on the photochemistry of porphyrins pigments in solution and in lipid bilayers form the basis for these arguments. In this way we can relate the structure of chlorophyll to its function in photosynthesis.

scholarly journals Lipid Tails Modulate Antimicrobial Peptide Membrane Incorporation and Activity

2021 ◽  
Author(s):  
Lawrence R. Walker ◽  
Michael T Marty
Keyword(s):  
Lipid Bilayers ◽  
Tail Length ◽  
Native Mass Spectrometry ◽  
Unsaturated Lipid ◽  
Large Unilamellar Vesicle ◽  
Unsaturated Lipids ◽  
Head Groups ◽  
Fluid Bilayers ◽  
Lipid Nanodiscs ◽  
Assembly Pathways

Antimicrobial peptides (AMPs) are cationic, amphipathic peptides that interact directly with lipid bilayers. AMPs generally interact with anionic lipid head groups, but it is less clear how the lipid tail length and saturation modulates interactions with membranes. Here, we used native mass spectrometry to measure the stoichiometry of three different AMPs-LL-37, indolicidin, and magainin-2-in lipid nanodiscs. We also measured the activity of these AMPs in large unilamellar vesicle leakage assays. We found that LL-37 formed specific hexamer complexes but with different assembly pathways and affinities that depended on the bilayer thickness. LL-37 was also most active in lipid bilayers containing longer, unsaturated lipids. In contrast, indolicidin incorporated to a higher degree into more fluid lipid bilayers but was more active with thinner, less fluid bilayers. Finally, magainin-2 incorporated to a higher degree into longer, unsaturated bilayers and showed more activity in these same conditions. Together, these data show that higher amounts of peptide incorporation generally led to higher activity and that AMPs tend to incorporate more into longer unsaturated lipid bilayers. However, the activity of AMPs was not always directly related to amount of peptide incorporated.

scholarly journals The chain order of binary unsaturated lipid bilayers modulated by aromatic-residue-containing peptides: an ATR-FTIR spectroscopy study

RSC Advances ◽  
2017 ◽  
Vol 7 (47) ◽  
pp. 29386-29394 ◽  
Author(s):  
Bo Peng ◽  
Xiao-Yan Ding ◽  
Chao Sun ◽  
Ya-Nan Yang ◽  
Yu-Jiao Gao ◽  
...  
Keyword(s):  
Ftir Spectroscopy ◽  
Lipid Bilayers ◽  
Lipid Composition ◽  
Peptide Binding ◽  
Spectroscopy Study ◽  
Unsaturated Lipid ◽  
Aromatic Residues ◽  
Structural Context ◽  
Chain Order ◽  
The Stability

It highlights the importance of aromatic residues in influencing peptide binding to the membrane, demonstrates that the stability of the membranes depends on the lipid composition and the sequence, structural context, and orientation of the peptides.

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