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DiPasquale M, Marquardt D. Perceiving the functions of vitamin E through neutron and X-ray scattering. Adv Colloid Interface Sci 2024; 330:103189. [PMID: 38824717 DOI: 10.1016/j.cis.2024.103189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 05/14/2024] [Accepted: 05/17/2024] [Indexed: 06/04/2024]
Abstract
Take your vitamins, or don't? Vitamin E is one of the few lipophilic vitamins in the human diet and is considered an essential nutrient. Over the years it has proven to be a powerful antioxidant and is commercially used as such, but this association is far from linear in physiology. It is increasingly more likely that vitamin E has multiple legitimate biological roles. Here, we review past and current work using neutron and X-ray scattering to elucidate the influence of vitamin E on key features of model membranes that can translate to the biological function(s) of vitamin E. Although progress is being made, the hundred year-old mystery remains unsolved.
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Affiliation(s)
| | - Drew Marquardt
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada; Department of Physics, University of Windsor, Windsor, Ontario, Canada.
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2
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Gamage RS, Smith BD. Spontaneous Transfer of Indocyanine Green from Liposomes to Albumin Is Inhibited by the Antioxidant α-Tocopherol. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:11950-11961. [PMID: 36126324 PMCID: PMC9897306 DOI: 10.1021/acs.langmuir.2c01715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Indocyanine Green (ICG) is a clinically approved organic dye with near-infrared absorption and fluorescence. Over the years, many efforts to improve the photophysical and pharmacokinetic properties of ICG have investigated numerous nanoparticle formulations, especially liposomes with membrane-embedded ICG. A series of systematic absorption and fluorescence experiments, including FRET experiments using ICG as a fluorescence energy acceptor, found that ICG transfers spontaneously from liposomes to albumin protein residing in the external solution with a half-life of ∼10 min at 37 °C. Moreover, transfer of ICG from liposome membranes to external albumin reduces light-activated leakage from thermosensitive liposomes with membrane-embedded ICG. A survey of lipophilic liposome additives discovered that the presence of clinically approved antioxidant, α-tocopherol, greatly increases ICG retention in the liposomes (presumably by forming favorable aromatic stacking interactions), inhibits ICG photobleaching and prevents albumin-induced reduction of light-triggered liposome leakage. This new insight will help researchers with the specific task of optimizing ICG-containing liposomes for fluorescence imaging or phototherapeutics. More broadly, the results suggest a broader design concept concerning light triggered liposome leakage, that is, proximity of the light absorbing dye to the bilayer membrane is a critical design feature that impacts the extent of liposome leakage.
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3
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DiPasquale M, Nguyen MHL, Pabst G, Marquardt D. Partial Volumes of Phosphatidylcholines and Vitamin E: α-Tocopherol Prefers Disordered Membranes. J Phys Chem B 2022; 126:6691-6699. [PMID: 36027485 DOI: 10.1021/acs.jpcb.2c04209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Despite its discovery over 95 years ago, the biological and nutritional roles of vitamin E remain subjects of much controversy. Though it is known to possess antioxidant properties, recent assertions have implied that vitamin E may not be limited to this function in living systems. Through densitometry measurements and small-angle X-ray scattering we observe favorable interactions between α-tocopherol and unsaturated phospholipids, with more favorable interactions correlating to an increase in lipid chain unsaturation. Our data provide evidence that vitamin E may preferentially associate with oxygen sensitive lipids─an association that is considered innate for a viable membrane antioxidant.
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Affiliation(s)
- Mitchell DiPasquale
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada
| | - Michael H L Nguyen
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada
| | - Georg Pabst
- Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, University of Graz, Graz 8010, Austria.,BioTechMed-Graz, Graz 8010, Austria
| | - Drew Marquardt
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada.,Department of Physics, University of Windsor, Windsor, Ontario N9B 3P4, Canada
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4
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Atkinson J, Marquardt D, DiPasquale M, Harroun T. From fat to bilayers: Understanding where and how vitamin E works. Free Radic Biol Med 2021; 176:73-79. [PMID: 34555454 DOI: 10.1016/j.freeradbiomed.2021.09.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/30/2021] [Accepted: 09/11/2021] [Indexed: 11/16/2022]
Abstract
Vitamin E was one of the last fat-soluble vitamins to be discovered. We provide here an historical review of the discovery and the increasingly more detailed understanding of the role of α-tocopherol both as an antioxidant and as a structural component of phospholipid bilayer membranes. Despite the detailed descriptions now available of the orientation, location, and dynamics of α-tocopherol in lipid bilayers, there are still gaps in our knowledge of the effect of α-tocopherol and its potential receptors than control gene transcription.
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Affiliation(s)
- Jeffrey Atkinson
- Department of Chemistry, Brock University, St. Catharines, ON, L2S3A1, Canada.
| | - Drew Marquardt
- Department of Chemistry and Biochemistry, Windsor, ON, N9B 3P4, Canada; Department of Physics, Windsor, ON, N9B 3P4, Canada
| | | | - Thad Harroun
- Department of Physics, and Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, L2S3A1, Canada
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Molecular dynamics simulation study of the positioning and dynamics of α-tocopherol in phospholipid bilayers. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2021; 50:889-903. [PMID: 34052860 DOI: 10.1007/s00249-021-01548-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 10/25/2020] [Accepted: 05/17/2021] [Indexed: 01/18/2023]
Abstract
Using molecular dynamics simulations, we investigate the interaction of α-tocopherol (α-toc) with dipalmitoylphosphatidylcholine (DPPC), dimyristoylphosphatidylcholine (DMPC), palmitoyloleoylphosphatidylcholine (POPC), and palmitoyloleoylphosphatidylethanolamine (POPE) lipid bilayers. The goal is to develop a better understanding of the positioning and orientation of α-toc inside the bilayers; properties of significant relevance to α-toc anti-oxidant activity. We investigated bilayer systems with 128 lipids in the presence of either single or 14 α-toc molecules. The single α-toc bilayer systems were investigated via biased MD simulations in which the potential of mean force (PMF) and diffusivity were obtained as functions of the distance between α-toc head group and bilayer center. The higher α-toc concentration systems were investigated with unbiased MD simulations. For all four bilayers at both concentrations, the simulations show that the most probable location of the α-toc hydroxyl group is just below the lipid carbonyl group. Overall, the simulation results are in good agreement with existing experimental data except for the DMPC bilayer system for which some experiments predict α-toc to be located closer to bilayer center. The flip-flop frequency calculated shows that the α-toc flip-flop rate is sensitive to bilayer lipid type. In particular, α-toc has a much lower flip-flop rate in a POPE bilayer compared to the three PC lipid bilayers due to the smaller area per lipid in the POPE bilayer. For DMPC and POPC, the α-toc flip-flop rates are significantly higher at higher α-toc concentration and this appears to be related to the local structural disruption caused by α-toc clusters spanning the bilayer.
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Neunert G, Tomaszewska-Gras J, Baj A, Gauza-Włodarczyk M, Witkowski S, Polewski K. Phase Transitions and Structural Changes in DPPC Liposomes Induced by a 1-Carba-Alpha-Tocopherol Analogue. Molecules 2021; 26:molecules26102851. [PMID: 34064897 PMCID: PMC8151464 DOI: 10.3390/molecules26102851] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/22/2021] [Accepted: 05/04/2021] [Indexed: 11/26/2022] Open
Abstract
Steady-state emission spectroscopy of 1-anilino-8- naphthalene sulfonate (ANS) and 1,6-diphenyl-1,3,5-hexatriene (DPH), fluorescence anisotropy, and DSC methods were used to characterize the interactions of the newly synthesized 1-carba-alpha-tocopherol (CT) with a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) membrane. The DSC results showed significant perturbations in the DPPC structure for CT concentrations as low as 2 mol%. The main phase transition peak was broadened and shifted to lower temperatures in a concentration-dependent manner, and pretransition was abolished. Increasing CT concentrations induced the formation of new phases in the DPPC structure, leading to melting at lower temperatures and, finally, disruption of the ordered DPPC structure. Hydration and structural changes of the DPPC liposomes using ANS and DPH fluorescent probes, which are selectively located at different places in the bilayer, were studied. With the increased concentration of CT molecules in the DPPC liposomes, structural changes with the simultaneous formation of different phases of such mixture were observed. Temperature studies of such mixtures revealed a decrease in the temperature of the main phase transition and fluidization at decreasing temperatures related to increasing hydration in the bilayer. Contour plots obtained from concentration–temperature data with fluorescent probes allowed for identification of different phases, such as gel, ordered liquid, disordered liquid, and liquid crystalline phases. The CT molecule with a modified chromanol ring embedded in the bilayer led to H-bonding interactions, expelling water molecules from the interphase, thus introducing disorder and structural changes to the highly ordered gel phase.
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Affiliation(s)
- Grażyna Neunert
- Department of Physics and Biophysics, Faculty of Food Science and Nutrition, Poznan University of Life Sciences, Wojska Polskiego 38/42, 60-637 Poznan, Poland;
| | - Jolanta Tomaszewska-Gras
- Department of Food Quality and Safety Management, Faculty of Food Science and Nutrition, Poznan University of Life Sciences, Wojska Polskiego 31/33, 60-637 Poznan, Poland;
| | - Aneta Baj
- Department of Organic Chemistry, Faculty of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok, Poland; (A.B.); (S.W.)
| | - Marlena Gauza-Włodarczyk
- Department of Biophysics, Faculty of Medical Sciences, Poznan University of Medical Sciences, Grunwaldzka 6, 60-780 Poznan, Poland;
| | - Stanislaw Witkowski
- Department of Organic Chemistry, Faculty of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok, Poland; (A.B.); (S.W.)
| | - Krzysztof Polewski
- Department of Physics and Biophysics, Faculty of Food Science and Nutrition, Poznan University of Life Sciences, Wojska Polskiego 38/42, 60-637 Poznan, Poland;
- Correspondence: ; Tel.: +48-61-848-7501
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Diethylstilbestrol Modifies the Structure of Model Membranes and Is Localized Close to the First Carbons of the Fatty Acyl Chains. Biomolecules 2021; 11:biom11020220. [PMID: 33557377 PMCID: PMC7914449 DOI: 10.3390/biom11020220] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 01/28/2021] [Accepted: 02/01/2021] [Indexed: 12/23/2022] Open
Abstract
The synthetic estrogen diethylstilbestrol (DES) is used to treat metastatic carcinomas and prostate cancer. We studied its interaction with membranes and its localization to understand its mechanism of action and side-effects. We used differential scanning calorimetry (DSC) showing that DES fluidized the membrane and has poor solubility in DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) in the fluid state. Using small-angle X-ray diffraction (SAXD), it was observed that DES increased the thickness of the water layer between phospholipid membranes, indicating effects on the membrane surface. DSC, X-ray diffraction, and 31P-NMR spectroscopy were used to study the effect of DES on the Lα-to-HII phase transition, and it was observed that negative curvature of the membrane is promoted by DES, and this effect may be significant to understand its action on membrane enzymes. Using the 1H-NOESY-NMR-MAS technique, cross-relaxation rates for different protons of DES with POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) protons were calculated, suggesting that the most likely location of DES in the membrane is with the main axis parallel to the surface and close to the first carbons of the fatty acyl chains of POPC. Molecular dynamics simulations were in close agreements with the experimental results regarding the location of DES in phospholipids bilayers.
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Ausili A, Gómez-Murcia V, Candel AM, Beltrán A, Torrecillas A, He L, Jiang Y, Zhang S, Teruel JA, Gómez-Fernández JC. A comparison of the location in membranes of curcumin and curcumin-derived bivalent compounds with potential neuroprotective capacity for Alzheimer's disease. Colloids Surf B Biointerfaces 2020; 199:111525. [PMID: 33373844 DOI: 10.1016/j.colsurfb.2020.111525] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/14/2020] [Accepted: 12/07/2020] [Indexed: 11/30/2022]
Abstract
Curcumin and two bivalent compounds, namely 17MD and 21MO, both obtained by conjugation of curcumin with a steroid molecule that acts as a membrane anchor, were comparatively studied. When incorporated into 1,2-dipalmitoyl-sn-glycero-3-phosphocholine the compounds showed a very limited solubility in the model membranes. Curcumin and the two bivalent compounds were also incorporated in membranes of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and quenching the fluorescence of pure curcumin or of the curcumin moiety in the bivalent compounds by acrylamide it was seen that curcumin was accessible to this water soluble quencher but the molecule was somehow located in a hydrophobic environment. This was confirmed by quenching with doxyl-phosphatidylcholines, indicating that the curcumin moieties of 17MD and 21MO were in a more polar environment than pure curcumin itself. 1H NOESY MAS-NMR analysis supports this notion by showing that the orientation of curcumin was parallel to the plane of the membrane surface close to C2 and C3 of the fatty acyl chains, while the curcumin moiety of 17MD and 21MO positioned close to the polar part of the membrane with the steroid moiety in the centre of the membrane. Molecular dynamics studies were in close agreement with the experimental results with respect to the likely proximity of the protons studied by NMR and show that 17MD and 21MO have a clear tendency to aggregate in a fluid membrane. The anchorage of the bivalent compounds to the membrane leaving the curcumin moiety near the polar part may be very important to facilitate the bioactivity of the curcumin moiety when used as anti-Alzheimer drugs.
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Affiliation(s)
- Alessio Ausili
- Departamento De Bioquímica y Biología Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum", Universidad de Murcia, Apartado de Correos 4021, Murcia, E-30080, Spain
| | - Victoria Gómez-Murcia
- Departamento de Farmacología, Facultad de Medicina, IMIB, Regional Campus of International Excellence "Campus Mare Nostrum", Universidad de Murcia, Apartado de Correos 4021, Murcia, E-30080, Spain
| | - Adela M Candel
- Departamento De Bioquímica y Biología Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum", Universidad de Murcia, Apartado de Correos 4021, Murcia, E-30080, Spain
| | - Andrea Beltrán
- Departamento De Bioquímica y Biología Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum", Universidad de Murcia, Apartado de Correos 4021, Murcia, E-30080, Spain
| | - Alejandro Torrecillas
- Departamento De Bioquímica y Biología Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum", Universidad de Murcia, Apartado de Correos 4021, Murcia, E-30080, Spain
| | - Liu He
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298, United States
| | - Yuqi Jiang
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298, United States
| | - Shijun Zhang
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298, United States
| | - José A Teruel
- Departamento De Bioquímica y Biología Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum", Universidad de Murcia, Apartado de Correos 4021, Murcia, E-30080, Spain
| | - Juan C Gómez-Fernández
- Departamento De Bioquímica y Biología Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum", Universidad de Murcia, Apartado de Correos 4021, Murcia, E-30080, Spain.
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9
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Cavazos AT, Kinnun JJ, Williams JA, Wassall SR. Vitamin E - phosphatidylethanolamine interactions in mixed membranes with sphingomyelin: Studies by 2H NMR. Chem Phys Lipids 2020; 231:104910. [PMID: 32492380 DOI: 10.1016/j.chemphyslip.2020.104910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/14/2020] [Accepted: 03/21/2020] [Indexed: 01/13/2023]
Abstract
Among the structurally diverse collection of lipids that comprise the membrane lipidome, polyunsaturated phospholipids are particularly vulnerable to oxidation. The role of α-tocopherol (vitamin E) is to protect this influential class of membrane phospholipid from oxidative damage. Whether lipid-lipid interactions play a role in supporting this function is an unanswered question. Here, we compare the molecular organization of polyunsaturated 1-[2H31]palmitoyl-2-docosahexaenoylphosphatidylethanolamine (PDPE-d31) and, as a control, monounsaturated 1-[2H31]palmitoyl-2-oleoylphosphatidylethanolamine (POPE-d31) mixed with sphingomyelin (SM) and α-tocopherol (α-toc) (2:2:1 mol) by solid-state 2H NMR spectroscopy. In both cases the effect of α-toc appears similar. Spectral moments reveal that the main chain melting transition of POPE-d31 and PDPE-d31 is broadened beyond detection. A spectral component attributed to the formation of inverted hexagonal HII phase in coexistence with lamellar Lα phase by POPE-d31 (20 %) and PDPE-d31 (18 %) is resolved following the addition of α-toc. Order parameters in the remaining Lα phase are increased slightly more for POPE-d31 (7%) than PDPE-d31 (4%). Preferential interaction with polyunsaturated phospholipid is not apparent in these results. The propensity for α-toc to form phase structure with negative curvature that is more tightly packed at the membrane surface, nevertheless, may restrict the contact of free radicals with lipid chains on phosphatidylethanolamine molecules that accumulate polyunsaturated fatty acids.
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Affiliation(s)
- Andres T Cavazos
- Department of Physics, Indiana University-Purdue University, Indianapolis, IN, 46202, United States
| | - Jacob J Kinnun
- Department of Physics, Indiana University-Purdue University, Indianapolis, IN, 46202, United States
| | - Justin A Williams
- Department of Physics, Indiana University-Purdue University, Indianapolis, IN, 46202, United States
| | - Stephen R Wassall
- Department of Physics, Indiana University-Purdue University, Indianapolis, IN, 46202, United States.
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Harper PE, Cavazos AT, Kinnun JJ, Petrache HI, Wassall SR. Vitamin E Promotes the Inverse Hexagonal Phase via a Novel Mechanism: Implications for Antioxidant Role. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:4908-4916. [PMID: 32295345 DOI: 10.1021/acs.langmuir.0c00176] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Vitamin E (α-tocopherol) and a range of other biological compounds have long been known to promote the HII (inverted hexagonal) phase in lipids. Now, it has been well established that purely hydrophobic lipids such as dodecane promote the HII phase by relieving extensive packing stress. They do so by residing deep within the hydrocarbon core. However, we argue from X-ray diffraction data obtained with 1-palmitoyl-2-oleoylphosphatidylcholine (POPE) and 1,2-dioleoylphosphatidylcholine (DOPE) that α-tocopherol promotes the HII phase by a different mechanism. The OH group on the chromanol moiety of α-tocopherol anchors it near the aqueous interface. This restriction combined with the relatively short length of α-tocopherol (as compared to DOPE and POPE) means that α-tocopherol promotes the HII phase by relieving compressive packing stress. This observation offers new insight into the nature of packing stress and lipid biophysics. With the deeper understanding of packing stress offered by our results, we also explore the role that molecular structure plays in the primary function of vitamin E, which is to prevent the oxidation of polyunsaturated membrane lipids.
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Affiliation(s)
- Paul E Harper
- Department of Physics and Astronomy, Calvin University, Grand Rapids, Michigan 49546-4403, United States
| | - Andres T Cavazos
- Department of Physics, IUPUI, Indianapolis, Indiana 46202-3273, United States
| | - Jacob J Kinnun
- Department of Physics, IUPUI, Indianapolis, Indiana 46202-3273, United States
| | - Horia I Petrache
- Department of Physics, IUPUI, Indianapolis, Indiana 46202-3273, United States
| | - Stephen R Wassall
- Department of Physics, IUPUI, Indianapolis, Indiana 46202-3273, United States
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Ausili A, Clemente J, Pons-Belda ÓD, de Godos A, Corbalán-García S, Torrecillas A, Teruel JA, Gomez-Fernández JC. Interaction of Vitamin K 1 and Vitamin K 2 with Dimyristoylphosphatidylcholine and Their Location in the Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:1062-1073. [PMID: 31927934 DOI: 10.1021/acs.langmuir.9b03552] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Vitamin K1 and vitamin K2 play very important biological roles as members of chains of electron transport as antioxidants in membranes and as cofactors for the posttranslational modification of proteins that participate in a number of physiological functions such as coagulation. The interaction of these vitamins with dimyristoylphosphatidylcholine (DMPC) model membranes has been studied by using a biophysical approach. It was observed by using differential scanning calorimetry that both vitamins have a very limited miscibility with DMPC and they form domains rich in the vitamins at high concentrations. Experiments using X-ray diffraction also showed the formation of different phases as a consequence of the inclusion of either vitamin K at temperatures below the phase transition. However, in the fluid state, a homogeneous phase was detected, and a decrease in the thickness of the membrane was accompanied by an increase in the water layer thickness. 2H NMR spectroscopy showed that both vitamins K induced a decrease in the onset of the phase transition, which was bigger for vitamin K1, and both vitamins decreased the order of the membrane as seen through the first moment (M1). 1H NOESY MAS-NMR showed that protons located at the rings or at the beginning of the lateral chain of both vitamins K interacted with a clear preference with protons located in the polar part of DMPC. On the other hand, protons located on the lateral chain have a nearer proximity with the methyl end of the myristoyl chains of DMPC. In agreement with the 2H NMR, ATR-FTIR (attenuated total reflectance Fourier transform infrared spectroscopy) indicated that both vitamins decreased the order parameters of DMPC. It was additionally deduced that the lateral chains of both vitamins were oriented almost in parallel to the myristoyl chains of the phospholipid.
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Affiliation(s)
- Alessio Ausili
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Javier Clemente
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Óscar D Pons-Belda
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Ana de Godos
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Senena Corbalán-García
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Alejandro Torrecillas
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - José A Teruel
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Juan C Gomez-Fernández
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
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12
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Lachmayr KK, Sita LR. Small‐Molecule Modulation of Soft‐Matter Frank–Kasper Phases: A Method for Adding Function to Form. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201915416] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Kätchen K. Lachmayr
- Department of Chemistry and BiochemistryUniversity of Maryland College Park MD 20742 USA
| | - Lawrence R. Sita
- Department of Chemistry and BiochemistryUniversity of Maryland College Park MD 20742 USA
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13
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Lachmayr KK, Sita LR. Small‐Molecule Modulation of Soft‐Matter Frank–Kasper Phases: A Method for Adding Function to Form. Angew Chem Int Ed Engl 2020; 59:3563-3567. [DOI: 10.1002/anie.201915416] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Indexed: 01/27/2023]
Affiliation(s)
- Kätchen K. Lachmayr
- Department of Chemistry and BiochemistryUniversity of Maryland College Park MD 20742 USA
| | - Lawrence R. Sita
- Department of Chemistry and BiochemistryUniversity of Maryland College Park MD 20742 USA
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14
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Effects of oxidation on the physicochemical properties of polyunsaturated lipid membranes. J Colloid Interface Sci 2019; 538:404-419. [DOI: 10.1016/j.jcis.2018.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 11/29/2018] [Accepted: 12/02/2018] [Indexed: 12/13/2022]
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Kinnun JJ, Bittman R, Shaikh SR, Wassall SR. DHA Modifies the Size and Composition of Raftlike Domains: A Solid-State 2H NMR Study. Biophys J 2019; 114:380-391. [PMID: 29401435 DOI: 10.1016/j.bpj.2017.11.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/14/2017] [Accepted: 11/17/2017] [Indexed: 01/22/2023] Open
Abstract
Docosahexaenoic acid is an omega-3 polyunsaturated fatty acid that relieves the symptoms of a wide variety of chronic inflammatory disorders. The structural mechanism is not yet completely understood. Our focus here is on the plasma membrane as a site of action. We examined the molecular organization of [2H31]-N-palmitoylsphingomyelin (PSM-d31) mixed with 1-palmitoyl-2-docosahexaenoylphosphatylcholine (PDPC) or 1-palmitoyl-2-oleoylphosphatidylcholine (POPC), as a monounsaturated control, and cholesterol (chol) (1:1:1 mol) in a model membrane by solid-state 2H NMR. The spectra were analyzed in terms of segregation into ordered SM-rich/chol-rich (raftlike) and disordered PC-rich/chol-poor (nonraft) domains that are nanoscale in size. An increase in the size of domains is revealed when POPC was replaced by PDPC. Spectra that are single-component, attributed to fast exchange between domains (<45 nm), for PSM-d31 mixed with POPC and chol become two-component, attributed to slow exchange between domains (r > 30 nm), for PSM-d31 mixed with PDPC and chol. The resolution of separate signals from PSM-d31, and correspondingly from [3α-2H1]cholesterol (chol-d1) and 1-[2H31]palmitoyl-2-docosahexaenoylphosphatidylcholine (PDPC-d31), in raftlike and nonraft domains enabled us to determine the composition of the domains in the PDPC-containing membrane. Most of the lipid (28% SM, 29% chol, and 23% PDPC with respect to total lipid at 30°C) was found in the raftlike domain. Despite substantial infiltration of PDPC into raftlike domains, there appears to be minimal effect on the order of SM, implying the existence of internal structure that limits contact between SM and PDPC. Our results suggest a significant refinement to the model by which DHA regulates the architecture of ordered, sphingolipid-chol-enriched domains (rafts) in membranes.
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Affiliation(s)
- Jacob J Kinnun
- Department of Physics, Indiana University-Purdue University, Indianapolis, Indiana
| | - Robert Bittman
- Department of Chemistry and Biochemistry, Queens College of CUNY, Flushing, New York
| | - Saame Raza Shaikh
- Department of Nutrition, Gillings School of Global Public Health and School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Stephen R Wassall
- Department of Physics, Indiana University-Purdue University, Indianapolis, Indiana.
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Boonnoy P, Karttunen M, Wong-ekkabut J. Does α-Tocopherol Flip-Flop Help to Protect Membranes Against Oxidation? J Phys Chem B 2018; 122:10362-10370. [DOI: 10.1021/acs.jpcb.8b09064] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
| | | | - Jirasak Wong-ekkabut
- Thailand Center of Excellence in Physics, Commission on Higher Education, Bangkok 10400, Thailand
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17
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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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18
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Leng X, Zhu F, Wassall SR. Vitamin E Has Reduced Affinity for a Polyunsaturated Phospholipid: An Umbrella Sampling Molecular Dynamics Simulations Study. J Phys Chem B 2018; 122:8351-8358. [PMID: 30111105 DOI: 10.1021/acs.jpcb.8b05016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Vitamin E is an essential micronutrient. The primary function of this lipid-soluble antioxidant is to protect membrane phospholipids from oxidation. Whether vitamin E preferentially interacts with polyunsaturated phospholipids to optimize protection of the lipid species most vulnerable to oxidative attack has been an unanswered question for a long time. In this work, we compared the binding of α-tocopherol (αtoc), the form of vitamin E retained by the human body, in bilayers composed of polyunsaturated 1-stearoyl-2-docosahexaenoylphosphatidylcholine (SDPC, 18:0-22:6PC) and, as a control, monounsaturated 1-stearoyl-2-oleoylphosphatidylcholine (SOPC, 18:0-18:1PC) by umbrella sampling molecular dynamics simulations. From the potential of mean force as a function depth within the bilayer, we find that the binding energy of αtoc is less in SDPC (Δ Gbind = 16.7 ± 0.3 kcal/mol) than that in SOPC (Δ Gbind = 18.3 ± 0.4 kcal/mol). The lower value in SDPC is ascribed to the high disorder of polyunsaturated fatty acids that produces a less tightly packed arrangement. Deformation of the bilayer is observed during desorption, indicating that phosphatidylcholine (PC)-PC and αtoc-PC interactions contribute to the binding energy. Our results do not support the proposal that vitamin E interacts more favorably with polyunsaturated phospholipids.
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Affiliation(s)
- Xiaoling Leng
- Department of Physics , IUPUI , Indianapolis , Indiana 46202-3273 , United States
| | - Fangqiang Zhu
- Department of Physics , IUPUI , Indianapolis , Indiana 46202-3273 , United States
| | - Stephen R Wassall
- Department of Physics , IUPUI , Indianapolis , Indiana 46202-3273 , United States
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Frolova TS, Sharapov SZ, Sinitsyna OI, Tolstikova TG, Grigoriev IA, Morozov SV, Yushkova YV. New Ionic Conjugates Based on α-Tocopheryl Succinate as Potential Cytotoxic Agents. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2018. [DOI: 10.1134/s1068162018030068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Ausili A, Torrecillas A, de Godos AM, Corbalán-García S, Gómez-Fernández JC. Phenolic Group of α-Tocopherol Anchors at the Lipid-Water Interface of Fully Saturated Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:3336-3348. [PMID: 29447442 DOI: 10.1021/acs.langmuir.7b04142] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
α-Tocopherol is considered to carry on a very important role as an antioxidant for membranes and lipoproteins and other biological roles as membrane stabilizers and bioactive lipids. Given its essential role, it is very important to fully understand its location in the membrane. In this work, the vertical location of vitamin E in saturated membranes has been studied using biophysical techniques. Small- and wide-angle X-ray diffraction experiments show that α-tocopherol alters the water layer between bilayers in both 1,2-dimyristoyl- sn-glycero-3-phosphocholine (DMPC) and 1,2-dipalmitoyl- sn-glycero-3-phosphocholine (DPPC), indicating its proximity to this surface. The quenching of the intrinsic fluorescence of α-tocopherol indicates a low quenching efficiency by acrylamide and a higher quenching by 5-doxyl-PC than by 9- and 16-doxyl-PC. These results suggest that in both DMPC and DPPC membranes, the chromanol ring is not far away from the surface of the membrane but within the bilayer. 1H nuclear Overhauser enhancement spectroscopy magic-angle spinning-nuclear magnetic resonance studies showed that α-tocopherol is localized in a similar manner in DMPC and DPPC membranes, with the chromanol ring embedded in the upper part of the hydrophobic bilayer. Using attenuated total reflection-Fourier transform infrared spectroscopy, it was observed that the tail chain of α-tocopherol lies nearly parallel to the acyl chains of DMPC and DPPC. Taking these results together, it was concluded that in both DMPC and DPPC, the hydroxyl group of the chromanol ring will establish hydrogen bonding with water on the membrane surface, and the main axis of the α-tocopherol molecule will be perpendicular to the bilayer plane.
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Affiliation(s)
- Alessio Ausili
- Departamento de Bioquímica y Biología Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence Mare Nostrum , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Alejandro Torrecillas
- Departamento de Bioquímica y Biología Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence Mare Nostrum , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Ana M de Godos
- Departamento de Bioquímica y Biología Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence Mare Nostrum , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Senena Corbalán-García
- Departamento de Bioquímica y Biología Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence Mare Nostrum , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Juan C Gómez-Fernández
- Departamento de Bioquímica y Biología Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence Mare Nostrum , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
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