Using a combination of X-ray diffraction data from oriented films and multilamellar liposomes of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) in the subgel phase, we have established the presence of a 2D molecular lattice containing two lipid molecules. The proposed 2D lattice is consistent with all the X-ray diffraction data on the subgel phase of DPPC available in the literature. In this phase, the DPPC molecules are ordered in the plane of the bilayer and are also found to be positionally correlated across a single bilayer but not with those in adjacent bilayers. We also present the possible molecular arrangements for the proposed lattice.
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http://dx.doi.org/10.1021/bi00014a023 | DOI Listing |
Biophys J
March 2023
Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania; Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland.
High-resolution x-ray data are reported for the ordered phases of long-chain di-monounsaturated C22:1 phosphocholine lipid bilayers. Similar to PC lipids that have saturated chains, diC22:1PC has a subgel phase and a gel phase, but dissimilarly, we find no ripple phase. Our quantitative focus is on the structure of the gel phase.
View Article and Find Full Text PDFJ Phys Chem B
September 2021
Institute of Applied Dermatopharmacy at Martin Luther University Halle-Wittenberg, Weinbergweg 23, 06120 Halle (Saale), Germany.
Chem Phys Lipids
September 2021
Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University, 2-1 Minamijosanjima-cho, Tokushima, 770-8513, Japan. Electronic address:
The formation of subgel (so-called hydrated crystal) phase of membranes of ether-linked phospholipids, dialkylphosphatidylcholines containing linear saturated alkyl chain (Cn = 14, 16 and 18), was examined under atmospheric and high pressure. The results of differential scanning calorimetry in 50 wt% aqueous ethylene glycol solution and water showed that these PC membranes undergo the subtransition from the subgel phase to the gel phase at a low temperature with or without the thermal pretreatment of lipid samples called annealing. The subtransition in water was clearly observed by light-transmittance measurements under high pressure and the transition temperature increased by applying pressure.
View Article and Find Full Text PDFChembiochem
January 2020
Max Planck Institute of Colloids and Interfaces, Biomolecular Systems Department, Am Mühlenberg 1, 14476, Potsdam, Germany.
α-Galactosylceramide (α-GalCer; KRN7000) is a ligand for the glycoprotein CD1d that presents lipid antigens to natural killer T cells. Therefore, KRN7000 as well as some modified versions thereof have been widely investigated as part of novel immunotherapies. To examine the impact of structural modification, we investigated KRN7000 and C6-modified KRN7000 at the air-liquid interface using monolayer isotherms, BAM, IRRAS, GIXD, and TRXF.
View Article and Find Full Text PDFChemphyschem
October 2018
Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, SaltLake, Kolkata, 700 106, India.
It is well accepted in contemporary biology that an ∼30 Å thick lipid bilayer film around living cells is a matter of life and death as the film typically delimits the environments that serve as a crucial margin. The dynamic organization of lipid molecules both across the lipid bilayer and in the lateral dimension are known to be crucial for cellular transport and molecular recognition by important biological macromolecules. Here, we study dilute (20 mM) Dioctadecyldimethylammonium bromide (DODAB) vesicles at different temperatures in aqueous dispersion with well-defined phases namely liquid crystalline, gel and subgel.
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