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Dar AA, Chat OA. Cosolubilization of Coumarin30 and Warfarin in Cationic, Anionic, and Nonionic Micelles: A Micelle–Water Interfacial Charge Dependent FRET. J Phys Chem B 2015; 119:11632-42. [DOI: 10.1021/jp511978h] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Aijaz Ahmad Dar
- Department of Chemistry, University of Kashmir, Srinagar-190006, Jammu and Kashmir India
| | - Oyais Ahmad Chat
- Department of Chemistry, University of Kashmir, Srinagar-190006, Jammu and Kashmir India
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Rana DK, Rakshit S, Dhar S, Bhattacharya SC. Spectroscopic probing of the microenvironment of 7-oxy(5-selenocyanato-pentyl)-2H-1-benzopyran-2-one in ionic and nonionic micelles. J Photochem Photobiol A Chem 2013. [DOI: 10.1016/j.jphotochem.2013.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Monné J, Díez Y, Puy J, Galceran J, Nelson A. Interpreting ion fluxes to channel arrays in monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:10581-8. [PMID: 17877378 DOI: 10.1021/la701447g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The exponentially decaying permeability model interprets the chronoamperometric currents arising from Tl+ reduction at a Hg electrode covered with a phospholipid monolayer (DOPC) containing gramicidin monomer by combining three processes: (i) the diffusion of an ion to a membrane surface with an array of channels, (ii) the conformational dynamics of the individual channels, and (iii) the passage of the ion through the channels. The introduction of a variable permeability allows us to uncouple the diffusion from the heterogeneous processes, given that the concentration of a species at the active surface can be obtained by semi-integration of the currents. Consideration of a reverse step for the dehydration process at the mouth of the channel allows the analysis of potential steps away from diffusion-limited conditions where a Nernstian-like behavior of the relevant parameter is observed. The model has been successfully applied to data with all trans retinol or benzo-alpha-pyrene as additive to the phospholipid monolayer and to monolayers without any additive at all.
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Affiliation(s)
- Josep Monné
- Departament de Química, Universitat de Lleida, Rovira Roure 191, 25198 Lleida, Spain
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Greube A, Müller K, Töpfer-Petersen E, Herrmann A, Müller P. Interaction of Fibronectin Type II Proteins with Membranes: The Stallion Seminal Plasma Protein SP-1/2. Biochemistry 2003; 43:464-72. [PMID: 14717601 DOI: 10.1021/bi035647l] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Seminal plasma of mammalians contains, among others, proteins that are characterized by the fibronectin (Fn) type II module. Our knowledge about the structure and the physiological function of seminal Fn type II proteins mainly originates from studies on PDC-109, the bovine representative of this protein family. The present work focuses on the equine protein SP-1/2 (also named HSP-1/2) with particular emphasis on its interaction with lipid membranes by employing the intrinsic protein fluorescence and a number of spin-labeled and fluorescent lipid analogues. The results indicate that the interaction of SP-1/2 with (lipid) membranes is similar to that of PDC-109 which can be explained by homologous amino acid sequences of both proteins. Like PDC-109, SP-1/2 has a specificity for phospholipids with the phosphocholine headgroup. Upon binding to lipid vesicles, the protein intercalates into the hydrophobic membrane core, resulting in a rigidification of the lipid phase and, at higher concentration, in a perturbation of membrane structure. However, compared with PDC-109, the impact of SP-1/2 on membranes is less intense in that the degree of protein-mediated immobilization of lipids was lower. Furthermore, different to PDC-109, SP-1/2 was not able to extract lipids from human red blood cells. The data are discussed with regard to similarities and species-specific differences of the function of seminal Fn type II proteins in the genesis of sperm cells.
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Affiliation(s)
- Alexa Greube
- Institut für Biologie, Mathematisch-Naturwissenschaftliche Fakultät I, Humboldt-Universität zu Berlin, Invalidenstrasse 43, D-10115 Berlin, Germany
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Vanounou S, Parola AH, Fishov I. Phosphatidylethanolamine and phosphatidylglycerol are segregated into different domains in bacterial membrane. A study with pyrene-labelled phospholipids. Mol Microbiol 2003; 49:1067-79. [PMID: 12890029 DOI: 10.1046/j.1365-2958.2003.03614.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To detect and characterize membrane domains that have been proposed to exist in bacteria, two kinds of pyrene-labelled phospholipids, 2-pyrene-decanoyl-phosphatidylethanolamine (PY-PE) and 2-pyrene-decanoyl-phosphatidylglycerol (PY-PG) were inserted into Escherichia coli or Bacillus subtilis membrane. The excimerization rate coefficient, calculated from the excimer-to-monomer ratio dependencies on the probe concentration, was two times higher for PY-PE than for PY-PG at 37 degrees C. This was ascribed to different local concentrations rather than to differences in mobility. The extent of mixing between the two fluorescent phospholipids, estimated by formation of their heteroexcimer, was found very low both in E. coli and B. subtilis, in contrast to model membranes. In addition, these two pyrene derivatives exhibited different temperature phase transitions and different detergent extractability, indicating that the surroundings of these phospholipids in bacterial membrane differ in organization and order. Inhibition of protein synthesis, leading to condensation of nucleoid and presumably to dissipation of membrane domains, indeed resulted in increased formation of heteroexcimers, broadening of phase transitions and equal detergent extractability of both probes. It is proposed that in bacterial membranes these phospholipids are segregated into distinct domains that differ in composition, proteo-lipid interaction and degree of order; the proteo-lipid domain being enriched by PE.
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Affiliation(s)
- Sharon Vanounou
- Department of Life Sciences, Ben-Gurion University of the Negev, POB 653, Beer-Sheva 84105, Israel
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Electronic energy transfer efficiency of mixed solutions of the donor–acceptor pairs: coumarin derivatives—acridine orange. J Photochem Photobiol A Chem 2002. [DOI: 10.1016/s1010-6030(02)00230-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Abstract
Potential step amperometry (chronoamperometry) of the Tl(I)/Tl(Hg) electrochemical reduction process has been used to investigate the underlying mechanisms of gramicidin activity in phospholipid monolayers. The experiments were carried out at gramicidin-modified dioleoyl phosphatidylcholine (DOPC)-coated electrodes. Application of a potential step to the coated electrode system results in a current transient that can be divided into two regions. An initial exponential decay of current corresponds to the inactivation of monomer channel conductance and a longer time scale quasi-steady-state represents the diffusion of ions to a bimolecular surface reaction. Concentrations of monomer conducting channels are relatively low, and the results indicate that two or more forms of gramicidin are in equilibrium with each other in the layer. Aromatic/conjugated compounds incorporated into the monolayer increase the reduction current by decreasing the rate of channel inactivation and increasing the stability of the conducting channel. This effect is positively correlated with the degree of the compound's aromaticity. The anomalous influence of alkali metal ions on the reduction current is consistent with the model of gramicidin being speciated in the monolayer in more than one form. The results have implications on the lability of the peptide conformation in biological membranes and its dependence on lipid environment, solution composition, and applied potential.
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Affiliation(s)
- A Nelson
- Marine Biological Association of the United Kingdom, The Laboratory, Plymouth PL1 2PB, United Kingdom.
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Kowert BA, Dang NC, Sobush KT, Seele LG. Diffusion of Aromatic Hydrocarbons in n-Alkanes and Cyclohexanes. J Phys Chem A 2001. [DOI: 10.1021/jp003002e] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bruce A. Kowert
- Department of Chemistry, Saint Louis University, St. Louis, Missouri 63103
| | - Nhan C. Dang
- Department of Chemistry, Saint Louis University, St. Louis, Missouri 63103
| | - Kurtis T. Sobush
- Department of Chemistry, Saint Louis University, St. Louis, Missouri 63103
| | - Louis G. Seele
- Department of Chemistry, Saint Louis University, St. Louis, Missouri 63103
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Karbownik M, Reiter RJ, Garcia JJ, Cabrera J, Burkhardt S, Osuna C, Lewi?ski A. Indole-3-propionic acid, a melatonin-related molecule, protects hepatic microsomal membranes from iron-induced oxidative damage: Relevance to cancer reduction. J Cell Biochem 2001. [DOI: 10.1002/1097-4644(20010601)81:3<507::aid-jcb1064>3.0.co;2-m] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Socaciu C, Jessel R, Diehl HA. Carotenoid incorporation into microsomes: yields, stability and membrane dynamics. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2000; 56:2799-2809. [PMID: 11145347 DOI: 10.1016/s1386-1425(00)00375-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The carotenoids beta-carotene (BC), lycopene (LYC), lutein (LUT), zeaxanthin (ZEA), canthaxanthin (CTX) and astaxanthin (ASTA) have been incorporated into pig liver microsomes. Effective incorporation concentrations in the range of about 1-6 nmol/mg microsomal protein were obtained. A stability test at room temperature revealed that after 3 h BC and LYC had decayed totally whereas, gradually, CTX (46%), LUT (21%), ASTA (17%) and ZEA (5%) decayed. Biophysical parameters of the microsomal membrane were changed hardly by the incorporation of carotenoids. A small rigidification may occur. Membrane anisotropy seems to offer only a small tolerance for incorporation of carotenoids and seems to limit the achievable incorporation concentrations of the carotenoids into microsomes. Microsomes instead of liposomes should be preferred as a membrane model to study mutual effects of carotenoids and membrane dynamics.
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Affiliation(s)
- C Socaciu
- Department of Chemistry and Biochemistry, University of Agricultural Sciences and Vetinary Medicine, Romania
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Sastry S, Linderoth N. Molecular mechanisms of peptide loading by the tumor rejection antigen/heat shock chaperone gp96 (GRP94). J Biol Chem 1999; 274:12023-35. [PMID: 10207025 DOI: 10.1074/jbc.274.17.12023] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Complexes of gp96/GRP94 and peptides have been shown to elicit immunogenicity. We used fluorescence to understand peptide association with gp96. A pyrene-peptide conjugate was complexed with gp96 under a variety of conditions. At room temperature in low salt (20 mM NaCl), the peptide binds gp96 with a strong affinity (approximately 100-150 nM) and forms pyrene excimers, suggesting that the peptides were assembled as dimers. In high salt (2.2 M NaCl), although peptide binding was stronger (Ka approximately 55 nM) than in low salt, pyrene excimers were absent, implying that peptides were farther apart in the complex. Heat shock-activated peptide binding exhibited characteristics of both low salt and high salt modes of binding. Anisotropy and average lifetime of the bound pyrene suggested that peptides were probably located in a solvent-accessible hydrophobic binding pocket in low salt, whereas in high salt, the peptide may be buried in a less hydrophobic (more hydrophilic) environment. These results suggested that peptide-gp96 complexes were assembled in several different ways, depending on the assembly conditions. Resonance energy transfer between the intrinsic tryptophan(s) in gp96 and pyrene suggested that one or more tryptophan residues were within the critical Forster distance of 27-30 A from the pyrene in the bound peptide. It is proposed that peptides are assembled within higher order gp96 complexes (dimers, etc.) in a hydrophobic pocket and that there may be a conformational change in gp96 leading to an open configuration for peptide loading.
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Affiliation(s)
- S Sastry
- Laboratory of Molecular Genetics, The Rockefeller University, New York, New York 10021, USA.
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Shripathi V, Swamy GS, Chandrasekhar KS. Microviscosity of cucumber (Cucumis sativus L.) fruit protoplast membranes is altered by triacontanol and abscisic acid. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1323:263-71. [PMID: 9042348 DOI: 10.1016/s0005-2736(96)00193-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cucumber (Cucumis sativus L.) fruit protoplast membranes were probed with diphenylhexatriene (DPH) and pyrene, and also with two different plant growth regulators, triacontanol (TRIA) and abscisic acid (ABA). Fluorescence anisotropies of DPH and pyrene were measured after incorporating them into the membranes. The fluorescence lifetime of membrane-bound pyrene was also measured by using neodymium-doped yttrium aluminium garnet (Nd:YAG) laser of 35 ps pulses. The microviscosities of the membranes were calculated using the values of fluorescence anisotropy and lifetime. In the presence of TRIA and ABA, there was a sharp decrease in the fluorescence lifetime of pyrene. Similarly, there was also a decrease in the microviscosities of the membranes and increase in the rate of rotation of membrane-bound fluorophore, induced by the plant growth regulators. Furthermore, TRIA or TRIA + ABA could reduce the fluorescence anisotropy of both the fluorophores whereas, ABA decreased the anisotropy of only pyrene. This property of ABA may be due to its confinement to a specific spacial facet in the membrane. Fatty acid analysis indicated that membrane microviscosity fluctuations were not due to altered fatty acid composition alone as it is known that change in lipid-protein interaction would also alter the physical status of the membrane.
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Affiliation(s)
- V Shripathi
- Department of Botany, Karnatak, University, Dharwad, India
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Kölling A, Maldonado C, Ojeda F, Diehl HA. Membrane fluidity of microsomal and thymocyte membranes after X-ray and UV irradiation. RADIATION AND ENVIRONMENTAL BIOPHYSICS 1994; 33:303-313. [PMID: 7708904 DOI: 10.1007/bf01210452] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A brief literature review shows that ionizing radiation in biological membranes and in pure lipid membranes causes malondialdehyde formation, indicating lipid peroxidation processes. With respect to membrane fluidization by ionizing radiation, in pure lipid membranes rigidization effects are always reported, whereas contradictory results exist for biological membranes. Starting from the assumption that membrane proteins at least partly compensate for radiation effects leading to a rigidization of membrane lipid regions, pig liver microsomes, as a representative protein-rich intracellular membrane system, were irradiated with X-rays or UV-C with doses up to 120 Gy at a dose rate of 0.67 Gy min-1 and up to 0.73 J cm-2 at an exposure rate of 16.2 mJ cm-2 min-1, respectively. For both irradiation types a weak but significant positive correlation between malondialdehyde formation and membrane fluidity is revealed throughout the applied dose ranges. We conclude that the membraneous protein lipid interface increases its fluidity under radiation conditions. Also, thymocyte ghosts showed an increased fluidity after X-ray irradiation. Fluidity measurements were performed by the pyrene excimer method.
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Affiliation(s)
- A Kölling
- Abteilung Biophysik, Institut für Experimentelle Physik, Universität Bremen, Germany
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