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Neunert G, Tomaszewska-Gras J, Siejak P, Pietralik Z, Kozak M, Polewski K. Disruptive effect of tocopherol oxalate on DPPC liposome structure: DSC, SAXS, and fluorescence anisotropy studies. Chem Phys Lipids 2018; 216:104-113. [PMID: 30308198 DOI: 10.1016/j.chemphyslip.2018.10.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 09/26/2018] [Accepted: 10/05/2018] [Indexed: 02/05/2023]
Abstract
α-Tocopherol oxalate (TO), a tocopherol ester derivative, was investigated for its effect on the structural changes of fully hydrated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes, as a function of concentration and temperature, by applying differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), and DPH fluorescence anisotropy methods. The DSC and DPH anisotropy data indicated that TO embedded into DPPC membrane lowered the enthalpy (ΔHm) and temperature (Tm) of the main phase transition as well its cooperativity. Fluidization of the membrane at a lowered temperature was accompanied by formation of mixed structures of tocopherol-enriched domains. SAXS studies showed the formation of various ordered structures in DPPC gel-phase during incorporation of TO into the bilayer, as evidenced by the existence of lamellar phases with repeat distances (d) of 6.13 and 6.87 nm, assigned to TO-enriched domains and a lamellar, liquid-ordered DPPC phase with d = 8.45 nm at increasing TO concentrations with lowering and broadening of the Bragg peaks, and diffuse scattering, characteristic of a fluid Lα phase, were observed. In DPPC fluid-phase, the increasing presence of TO at low concentrations resulted in the appearance of a liquid-ordered phase with repeat d = 6.9 nm coexistent with a lamellar structure with d = 9.2 nm, assigned to liquid-disordered structures. An increasing repeat distance observed with raising the TO amount in the DPPC bilayer evolved from an increasing interlamellar water layer of increasing thickness. Presence of TO facilitated penetration of water molecules into the acyl chain region which decreased van der Waals interactions in the bilayer. The DSC, SAXS, and fluorescence anisotropy data established that TO exhibited pronounced disruptive activity in DPPC membranes compared to α-tocopherol. The driving force of the observed action was attributed to electrostatic and dipole interactions of the acidic moiety with the polar head group of phospholipids in the interface region of the bilayer.
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Affiliation(s)
- Grażyna Neunert
- Department of Physics and Biophysics, Faculty of Food and Nutrition Sciences, Poznan University of Life Sciences, Wojska Polskiego 38/42, 60-637, Poznan, Poland
| | - Jolanta Tomaszewska-Gras
- Department of Food Quality Management, Faculty of Food and Nutrition Sciences, Poznan University of Life Sciences, Wojska Polskiego 31/33, 60-624, Poznan, Poland
| | - Przemyslaw Siejak
- Department of Physics and Biophysics, Faculty of Food and Nutrition Sciences, Poznan University of Life Sciences, Wojska Polskiego 38/42, 60-637, Poznan, Poland
| | - Zuzanna Pietralik
- Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614, Poznań, Poland
| | - Maciej Kozak
- Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614, Poznań, Poland
| | - Krzysztof Polewski
- Department of Physics and Biophysics, Faculty of Food and Nutrition Sciences, Poznan University of Life Sciences, Wojska Polskiego 38/42, 60-637, Poznan, Poland.
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Imaging cerebroside-rich domains for phase and shape characterization in binary and ternary mixtures. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1357-67. [DOI: 10.1016/j.bbamem.2009.11.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2009] [Revised: 11/19/2009] [Accepted: 11/20/2009] [Indexed: 12/18/2022]
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Ambrosi S, Ragni L, Ambrosini A, Paccamiccio L, Mariani P, Fiorini R, Bertoli E, Zolese G. On the importance of anandamide structural features for its interactions with DPPC bilayers: effects on PLA2 activity. J Lipid Res 2005; 46:1953-61. [PMID: 15961786 DOI: 10.1194/jlr.m500121-jlr200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The acylethanolamide anandamide (AEA) occurs in a variety of mammalian tissues and, as a result of its action on cannabinoid receptors, exhibits several cannabimimetic activities. Moreover, some of its effects are mediated through interaction with an ion channel-type vanilloid receptor. However, the chemical features of AEA suggest that some of its biological effects could be related to physical interactions with the lipidic part of the membrane. The present work studies the effect of AEA-induced structural modifications of the dipalmitoylphosphatidylcholine (DPPC) bilayer on phospholipase A2 (PLA2) activity, which is strictly dependent on lipid bilayer features. This study, performed by 2-dimethylamino-(6-lauroyl)-naphthalene fluorescence, demonstrates that the effect of AEA on PLA2 activity is concentration-dependent. In fact, at low AEA/DPPC molar ratios (from R = 0.001 to R = 0.04), there is an increase of the enzymatic activity, which is completely inhibited for R = 0.1. X-ray diffraction data indicate that the AEA affects DPPC membrane structural properties in a concentration-dependent manner. Because the biphasic effect of increasing AEA concentrations on PLA2 activity is related to the induced modifications of membrane bilayer structural properties, we suggest that AEA-phospholipid interactions may be important to produce, at least in part, some of the similarly biphasic responses of some physiological activities to increasing concentrations of AEA.
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Affiliation(s)
- S Ambrosi
- Istituto di Biochimica, Università Politecnica delle Marche, 60131 Ancona, Italy
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Morris R, Cox H, Mombelli E, Quinn PJ. Rafts, little caves and large potholes: how lipid structure interacts with membrane proteins to create functionally diverse membrane environments. Subcell Biochem 2004; 37:35-118. [PMID: 15376618 DOI: 10.1007/978-1-4757-5806-1_2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
This chapter reviews how diverse lipid microdomains form in the membrane and partition proteins into different functional units that regulate cell trafficking, signalling and movement. We will concentrate upon five major issues: 1. the diversity of lipid structure that produces diverse microenvironments into which different subsets of proteins partition; 2. why ordered lipid domains exclude proteins, and the conditions required for select subsets of proteins to enter these domains; 3. the coupling of the inner and outer leaflets within ordered microdomains; 4. the effect of ordered lipid domains upon membrane properties including curvature and hydrophobicity that affect membrane fission, fusion and extension of filopodia; 5. the biological effects of these structural constraints; in particular how the properties of these domains combine to provide a very different signalling, trafficking and membrane fusion environment to that found in disordered (fluid mosaic) membrane. In addressing these problems, the review draws upon studies ranging from molecular dynamic modelling of lipid interactions, through physical studies of model membrane systems to structural and biological studies of whole cells, examining in the process problems inherent in visualising and purifying these microdomains. While the diversity of structure and function of ordered lipid microdomains is emphasised, some general roles emerge. In particular, the basis for having quite different, non-interacting ordered lipid domains on the same membrane is evident in the diversity of lipid structure and plays a key role in sorting signalling systems. The exclusion of ordered membrane from coated pits, and hence rapid endocytosis, is suggested to underlie the ability of highly ordered domains to establish stable secondary signalling systems required, for instance, in T cell receptor, insulin and neurotrophin signalling.
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Affiliation(s)
- Roger Morris
- Molecular Neurobiology Group, MRC Centre for Developmental Neurobiology, King's College, London, UK
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