Leishmania tropica: intraspecific polymorphisms in lipophosphoglycan correlate with transmission by different Phlebotomus species.
AuthorsSoares RP, Barron T, McCoy-Simandle K, Svobodova M, Warburg A, Turco SJ
JournalExp Parasitol
PubMed ID15208044
'Lipophosphoglycan (LPG) is a dominant surface molecule of Leishmania promastigotes which has been shown to be critical for parasite-sand fly vector interactions. To provide additional evidence for its importance in transmission, the LPGs from three Leishmania tropica strains that differ in their capability to infect sand flies, were biochemically characterized. ... More
The use of polyacrylamide gel electrophoresis for the analysis of acidic glycans labeled with the fluorophore 2-aminoacridone.
AuthorsJackson P, Pluskal MG, Skea W
JournalElectrophoresis
PubMed ID7813394
'A method is described for the electrophoretic analysis of fluorophore-labeled acidic glycans. Various glycoproteins were treated with the enzyme, peptide N-glycosidase F, to release mixtures of asparagine-linked glycans that were then labeled with the fluorophore 2-aminoacridone, and the resulting derivatives electrophoresed in high-density polyacrylamide gels. The acidic glycans were separated ... More
Receptor for anionic pyrene derivatives provides the basis for new biomembrane assays.
AuthorsWinschel CA, Kalidindi A, Zgani I, Magruder JL, Sidorov V
JournalJ Am Chem Soc
PubMed ID16231924
'This study describes a new receptor cyclen 1 capable of strong selective binding of pyrene-based anionic dyes under near-physiological conditions. This receptor comprises four naphthylthiourea groups tethered to a cyclen core via an ester linkage. The complexation behavior of cyclen 1 receptor is characterized by a series of (1)H NMR, ... More
Membrane-active properties of alpha-MSH analogs: aggregation and fusion of liposomes triggered by surface-conjugated peptides.
Authorsde Souza DL, Frisch B, Duportail G, Schuber F
JournalBiochim Biophys Acta
PubMed ID11779571
'Reaction of the melanotropin hormone analogs [Nle(4),D-Phe(7)]-alpha-MSH and [Nle(4),D-Phe(7)]-alpha-MSH(4-10), which were extended at their N-terminus by a thiol-functionalized spacer arm, with preformed liposomes containing thiol-reactive (phospho)lipid derivatives resulted in the aggregation of the vesicles and in a partial leakage of their inner contents. This aggregation/leakage effect, which was only observed ... More
The interaction of an antimicrobial decapeptide with phospholipid vesicles.
AuthorsChoi MJ, Kang SH, Kim S, Chang JS, Kim SS, Cho H, Lee KH
JournalPeptides
PubMed ID15165724
'Previously, by using combinatorial peptide libraries, we have identified activity-optimized decapeptide (KSL, KKVVFKVKFK-NH(2)), which exhibited a broad spectrum of the activity against bacteria and fungi without hemolytic activity. In order to examine lipid requirements and to understand the mode of KSL action, we investigated interactions of the peptide with vesicles ... More
Membrane fusion is induced by a distinct peptide sequence of the sea urchin fertilization protein bindin.
AuthorsUlrich AS, Otter M, Glabe CG, Hoekstra D
JournalJ Biol Chem
PubMed ID9642230
'Fertilization in the sea urchin is mediated by the membrane-associated acrosomal protein bindin, which plays a key role in the adhesion and fusion between sperm and egg. We have investigated the structure/function relationship of an 18-amino acid peptide fragment "B18," which represents the minimal membrane binding motif of the protein ... More
Direct fluorescence measurement of diffusional water permeability in the vasopressin-sensitive kidney collecting tubule.
AuthorsKuwahara M, Verkman AS
JournalBiophys J
PubMed ID3224144
'A fluorescence method has been developed for accurate and instantaneous measurement of transepithelial diffusional water permeability (Pd) in perfused kidney tubules based on the sensitivity of the fluorophore aminonapthelane trisulfonic acid (ANTS) to solution H2O/D2O content. The fluorescence of ANTS was 3.2-fold lower in an H2O buffer than in a ... More
Structure of human transferrin receptor oligosaccharides: conservation of site-specific processing.
AuthorsHayes GR, Williams AM, Lucas JJ, Enns CA
JournalBiochemistry
PubMed ID9136890
'The human transferrin receptor (TfR) has three N-linked oligosaccharides. A combination of site-directed mutagenesis and carbohydrate and protein chemistry was used to characterize the structures of the N-linked oligosaccharides and to map their locations. We find that the type of oligosaccharide at each position was unique for that particular site. ... More
Free fatty acid enhancement of cation-induced fusion of liposomes: synergism with synexin and other promoters of vesicle aggregation.
AuthorsMeers P, Hong K, Papahadjopoulos D
JournalBiochemistry
PubMed ID2973806
'The effect of free fatty acids on the cation-induced fusion of large unilamellar vesicles (liposomes) was investigated by using fluorescent assays which monitor the mixing of aqueous contents of liposomes. Overall fusion was modeled as a two-step process involving aggregation of vesicles followed by actual fusion. Different experimental conditions were ... More
Polymer-induced membrane fusion: potential mechanism and relation to cell fusion events.
AuthorsLentz BR
JournalChem Phys Lipids
PubMed ID8001186
'Poly(ethylene glycol) (PEG) is used widely to mediate cell-cell fusion in the production of somatic cell hybrids and in the fusion injection of macromolecules into cultured cells from erythrocytes or liposomes. However, little is known about the mechanisms by which PEG induces fusion of cell membranes, making its use much ... More
Developmental changes in water permeability across the alveolar barrier in perinatal rabbit lung.
AuthorsCarter EP, Umenishi F, Matthay MA, Verkman AS
JournalJ Clin Invest
PubMed ID9276723
'Lung fluid is reabsorbed rapidly at birth to permit alveolar respiration. We reported previously that expression of aquaporins (AQP) 1, 4, and 5 in rat lung increased just after birth. The hypothesis was tested that the increased AQP expression is associated with increased osmotic water permeability (Pf) between the airspace ... More
Pro-apoptotic cleavage products of Bcl-xL form cytochrome c-conducting pores in pure lipid membranes.
AuthorsBasañez G, Zhang J, Chau BN, Maksaev GI, Frolov VA, Brandt TA, Burch J, Hardwick JM, Zimmerberg J
JournalJ Biol Chem
PubMed ID11399768
'During apoptotic cell death, cells usually release apoptogenic proteins such as cytochrome c from the mitochondrial intermembrane space. If Bcl-2 family proteins induce such release by increasing outer mitochondrial membrane permeability, then the pro-apoptotic, but not anti-apoptotic activity of these proteins should correlate with their permeabilization of membranes to cytochrome ... More
Effects of cholesterol on the divalent cation-mediated interactions of vesicles containing amino and choline phospholipids.
AuthorsStamatotos L, Silvius JR
JournalBiochim Biophys Acta
PubMed ID3676317
'We have used assays of lipid probe mixing, contents mixing and contents leakage to monitor the divalent cation-mediated interactions between lipid vesicles containing phosphatidylserine (PS) as a minority component together with mixtures of phosphatidylethanolamine (PE), phosphatidylcholine (PC) or sphingomyelin, and cholesterol in varying proportions. The initial rates of calcium- and ... More
Interaction of a semirigid agonist with Torpedo acetylcholine receptor.
AuthorsKawai H, Cao L, Dunn SM, Dryden WF, Raftery MA
JournalBiochemistry
PubMed ID10747774
'The binding of the semirigid agonist [(3)H]arecolone methiodide to the Torpedo nicotinic acetylcholine receptor has been correlated with its functional properties measured both in flux studies with Torpedo membrane vesicles and by single-channel analysis after reconstitution in giant liposomes. Under both equilibrium and preequilibrium conditions, the binding of arecolone methiodide ... More
Morphological changes induced by phospholipase C and by sphingomyelinase on large unilamellar vesicles: a cryo-transmission electron microscopy study of liposome fusion.
AuthorsBasáñez G, Ruiz-Argüello MB, Alonso A, Goñi FM, Karlsson G, Edwards K
JournalBiophys J
PubMed ID9168038
'Cryo-transmission electron microscopy has been applied to the study of the changes induced by phospholipase C on large unilamellar vesicles containing phosphatidylcholine, as well as to the action of sphingomyelinase on vesicles containing sphingomyelin. In both cases vesicle aggregation occurs as the earliest detectable phenomenon; later, each system behaves differently. ... More
Interactions of monomeric rabbit neutrophil defensins with bilayers: comparison with dimeric human defensin HNP-2.
AuthorsHristova K, Selsted ME, White SH
JournalBiochemistry
PubMed ID8794771
'Human antimicrobial neutrophil defensin HNP-2 has been shown to form large multimeric pores in pure 1-palmitoyl-2-oleoyl phosphatidylglycerol (POPG) bilayers that lead to all-or-none release of vesicle contents [Wimley et al. (1994) Protein Sci.3, 1362-1373]. Because human neutrophil defensins form natural dimers in solution, the question arises as to the role ... More
The pre-transmembrane region of the human immunodeficiency virus type-1 glycoprotein: a novel fusogenic sequence.
AuthorsSuárez T, Nir S, Goñi FM, Saéz-Cirión A, Nieva JL
JournalFEBS Lett
PubMed ID10899326
'We have investigated membrane interactions and perturbations induced by NH(2)-DKWASLWNWFNITNWLWYIK-COOH (HIV(c)), representing the membrane interface-partitioning region that precedes the transmembrane anchor of the human immunodeficiency virus type-1 gp41 fusion protein. The HIV(c) peptide bound with high affinity to electrically neutral vesicles composed of dioleoylphosphatidylcholine, dioleoylphosphatidylethanolamine and cholesterol (molar ratio, 1:1:1), ... More
Generation of pH-sensitive liposomes: use of large unilamellar vesicles containing N-succinyldioleoylphosphatidylethanolamine.
AuthorsNayar R, Schroit AJ
JournalBiochemistry
PubMed ID4084501
'By use of a carboxylated derivative of phosphatidylethanolamine, N-succinyldioleoylphosphatidylethanolamine (COPE), pH-sensitive liposomes have been designed that have a wide range of leakage properties. The leakage rate of the vesicle contents, as determined by the release kinetics of the water-soluble fluorophore 8-aminonaphthalene-1,3,6-trisulfonic acid complexed with the quencher p-xylenebis(pyridinium) dibromide [Ellens, H., ... More
Stability and fusion of lipid vesicles containing headgroup-modified analogues of phosphatidylethanolamine.
AuthorsBrown PM, Silvius JR
JournalBiochim Biophys Acta
PubMed ID2930786
'We have used lipid mixing, contents mixing and contents-leakage assays to characterize the divalent cation-mediated interactions of vesicles composed of various headgroup-modified analogues of phosphatidylethanolamine, PE (N- and C-2-alkylated derivatives, and analogues with increased separations of the phosphoryl and amino groups) together with a low mole percentage of phosphatidylserine (PS). ... More
Effects of hemagglutinin fusion peptide on poly(ethylene glycol)-mediated fusion of phosphatidylcholine vesicles.
AuthorsHaque ME, McCoy AJ, Glenn J, Lee J, Lentz BR
JournalBiochemistry
PubMed ID11714278
'The effects of hemagglutinin (HA) fusion peptide (X-31) on poly(ethylene glycol)- (PEG-) mediated vesicle fusion in three different vesicle systems have been compared: dioleoylphosphatidylcholine (DOPC) small unilamellar vesicles (SUV) and large unilamellar vesicles (LUV) and palmitoyloleoylphosphatidylcholine (POPC) large unilamellar perturbed vesicles (pert. LUV). POPC LUVs were asymmetrically perturbed by hydrolyzing ... More
Leaky vesicle fusion induced by phosphatidylinositol-specific phospholipase C: observation of mixing of vesicular inner monolayers.
AuthorsVillar AV, Alonso A, Goñi FM
JournalBiochemistry
PubMed ID11087348
'Large unilamellar vesicles containing phosphatidylinositol (PI), neutral phospholipids, and cholesterol are induced to fuse by the catalytic activity of phosphatidylinositol-specific phospholipase C (PI-PLC). PI cleavage by PI-PLC is followed by vesicle aggregation, intervesicular lipid mixing, and mixing of vesicular aqueous contents. An average of 2-3 vesicles merge into a large ... More
Poly(ethylene glycol)-induced lipid mixing but not fusion between synthetic phosphatidylcholine large unilamellar vesicles.
'We have examined the effect of poly(ethylene glycol) (PEG) on stable large unilamellar vesicles formed by a rapid extrusion technique and composed of pure synthetic phosphatidylcholines. The lipid systems studied were the saturated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and the monounsaturated 1,2-dioleoyl-sn-glycerol-3-phosphocholine (DOPC). PEG at all concentrations (3.8-40 wt %) induced lipid mixing ... More
Poly(ethylene glycol)-induced fusion and rupture of dipalmitoylphosphatidylcholine large, unilamellar extruded vesicles.
AuthorsMassenburg D, Lentz BR
JournalBiochemistry
PubMed ID7690251
'High concentrations (> or = 20 wt %) of poly(ethylene glycol) (PEG) induce large, unilamellar, dipalmitoylphosphatidylcholine model membrane vesicles to fuse when the bilayers contain small amounts of amphipathic peturbant molecules. In addition to fusion, similar concentrations of PEG induce these vesicles to leak their contents. In this paper, we ... More
Structural evaluation of phospholipid bicelles for solution-state studies of membrane-associated biomolecules.
AuthorsGlover KJ, Whiles JA, Wu G, Yu N, Deems R, Struppe JO, Stark RE, Komives EA, Vold RR
JournalBiophys J
PubMed ID11566787
'Several complementary physical techniques have been used to characterize the aggregate structures formed in solutions containing dimyristoylphosphatidylcholine (DMPC)/dihexanoylphosphatidylcholine (DHPC) at ratios of < or =0.5 and to establish their morphology and lipid organization as that of bicelles. (31)P NMR studies showed that the DMPC and DHPC components were highly segregated ... More
Phospholipase C-promoted membrane fusion. Retroinhibition by the end-product diacylglycerol.
AuthorsNieva JL, Goñi FM, Alonso A
JournalBiochemistry
PubMed ID8424934
'The catalytic activity of phospholipase C induces fusion of pure lipid vesicles. When large unilamellar liposomes composed of phosphatidylcholine/phosphatidylethanolamine/cholesterol (2:1:1 mole ratio) are treated with phospholipase C, in the presence of 10 mM Ca2+, two enzyme effects can be distinguished: a fast one (half-time on the order of seconds) consisting ... More
Hydrophobic lipid additives affect membrane stability and phase behavior of N-monomethyldioleoylphosphatidylethanolamine.
Authorsvan Gorkom LC, Nie SQ, Epand RM
JournalBiochemistry
PubMed ID1731922
'The rate of formation of high-curvature intermediates or disordered cubic phases in N-methyldioleoylphosphatidylethanolamine (N-methyl-DOPE) dispersions with or without additives was studied by 31P NMR spectroscopy. In N-methyl-DOPE dispersions, both the L alpha liquid-crystalline phase and the hexagonal HII phase convert into phases of high curvature giving rise to isotropic 31P ... More
Proton-induced fusion of oleic acid-phosphatidylethanolamine liposomes.
AuthorsDüzgünes N, Straubinger RM, Baldwin PA, Friend DS, Papahadjopoulos D
JournalBiochemistry
PubMed ID4027231
'Liposomes composed of oleic acid and phosphatidylethanolamine (3:7 mole ratio) aggregate, become destabilized, and fuse below pH 6.5 in 150 mM NaCl. Fusion is monitored by (i) the intermixing of internal aqueous contents of liposomes, utilizing the quenching of aminonaphthalene-3,6,8-trisulfonic acid (ANTS) by N,N''-p-xylylenebis(pyridinium bromide) (DPX) encapsulated in two separate ... More
Association of a pH-sensitive peptide with membrane vesicles: role of amino acid sequence.
AuthorsParente RA, Nadasdi L, Subbarao NK, Szoka FC
JournalBiochemistry
PubMed ID2271551
'The solution properties and bilayer association of two synthetic 30 amino acid peptides, GALA and LAGA, have been investigated at pH 5 and 7.5. These peptides have the same amino acid composition and differ only in the positioning of glutamic acid and leucine residues which together compose 47% of each ... More
Reciprocal effects of apolipoprotein and lytic peptide analogs on membranes. Cross-sectional molecular shapes of amphipathic alpha helixes control membrane stability.
'Apolipoprotein (class A) amphipathic helixes are postulated to act as detergents by virtue of their cross-section being wedge-shaped. Using computer analysis of naturally occurring class A and lytic (class L) amphipathic helixes, we designed two archetypical model peptides. Analogs of these two peptides, incorporating substitutions or modifications of interfacial or ... More
Polar angle as a determinant of amphipathic alpha-helix-lipid interactions: a model peptide study.
AuthorsUematsu N, Matsuzaki K
JournalBiophys J
PubMed ID11023911
'Various physicochemical properties play important roles in the membrane activities of amphipathic antimicrobial peptides. To examine the effects of the polar angle, two model peptides, thetap100 and thetap180, with polar angles of 100 degrees and 180 degrees, respectively, were designed, and their interactions with membranes were investigated in detail. These ... More
Reversible adsorption and nonreversible insertion of Escherichia coli alpha-hemolysin into lipid bilayers.
AuthorsBakás L, Ostolaza H, Vaz WL, Goñi FM
JournalBiophys J
PubMed ID8889162
'Alpha-Hemolysin is an extracellular protein toxin (107 kDa) produced by some pathogenic strains of Escherichia coli. Although stable in aqueous medium, it can bind to lipid bilayers and produce membrane disruption in model and cell membranes. Previous studies had shown that toxin binding to the bilayer did not always lead ... More
Mechanism of the cell-penetrating peptide transportan 10 permeation of lipid bilayers.
AuthorsYandek LE, Pokorny A, Florén A, Knoelke K, Langel U, Almeida PF
JournalBiophys J
PubMed ID17218466
'The mechanism of the interaction between the cell-penetrating peptide transportan 10 (tp10) and phospholipid membranes was investigated. Tp10 induces graded release of the contents of phospholipid vesicles. The kinetics of peptide association with vesicles and peptide-induced dye efflux from the vesicle lumen were examined experimentally by stopped-flow fluorescence. The experimental ... More
The calcium-binding C-terminal domain of Escherichia coli alpha-hemolysin is a major determinant in the surface-active properties of the protein.
AuthorsSánchez-Magraner L, Viguera AR, García-Pacios M, Garcillán MP, Arrondo JL, de la Cruz F, Goñi FM, Ostolaza H
JournalJ Biol Chem
PubMed ID17324923
'alpha-Hemolysin (HlyA) from Escherichia coli is a protein toxin (1024 amino acids) that targets eukaryotic cell membranes, causing loss of the permeability barrier. HlyA consists of two main regions, an N-terminal domain rich in amphipathic helices, and a C-terminal Ca(2+)-binding domain containing a Gly- and Asp-rich nonapeptide repeated in tandem ... More
Microscale analysis of mucin-type O-glycans by a coordinated fluorophore-assisted carbohydrate electrophoresis and mass spectrometry approach.
AuthorsRobbe C, Capon C, Flahaut C, Michalski JC
JournalElectrophoresis
PubMed ID12601728
'The total glycan moiety was released in a single step from native glycoproteins by a nonreductive beta-elimination procedure. The generated oligosaccharides were further derivatized either with the hydrophobic fluorophore 2-aminoacridone (AMAC) or the charged 8-aminonaphthalene-1,3,6-trisulfonic acid (ANTS) fluorophore, and the resulting fluorescent derivatives were separated according to their hydrodynamic size ... More
Colicin Ia inserts into negatively charged membranes at low pH with a tertiary but little secondary structural change.
AuthorsMel SF, Stroud RM
JournalBiochemistry
PubMed ID8448167
'Colicin Ia, a member of the channel-forming family of colicins, inserts into model membranes in a pH- and lipid-dependent fashion. This insertion occurs with single-hit kinetics, requires negatively charged lipids in the target membrane, and increases in rate as the pH is reduced below 5.2. The low-pH requirement does not ... More
Glycophorin as a receptor for Escherichia coli alpha-hemolysin in erythrocytes.
AuthorsCortajarena AL, Goñi FM, Ostolaza H
JournalJ Biol Chem
PubMed ID11134007
'Escherichia coli alpha-hemolysin (HlyA) can lyse both red blood cells (RBC) and liposomes. However, the cells are lysed at HlyA concentrations 1-2 orders of magnitude lower than liposomes (large unilamellar vesicles). Treatment of RBC with trypsin, but not with chymotrypsin, reduces the sensitivity of RBC toward HlyA to the level ... More
Capillary zone electrophoresis of malto-oligosaccharides derivatized with 8-aminonaphthalene-1,3,6-trisulfonic acid.
AuthorsChiesa C, Horváth C
JournalJ Chromatogr
PubMed ID8408418
'Malto-oligosaccharides were derivatized via their reducing end with 8-aminonaphthalene-1,3,6-trisulfonic acid by reductive amination, and the separation and electrophoretic migration behavior of the labelled sugars were investigated by capillary zone electrophoresis. Series of linear malto-oligosaccharides were found particularly suitable for both the study of the effect of the operating conditions on ... More
Inhibition of Sendai virus fusion with phospholipid vesicles and human erythrocyte membranes by hydrophobic peptides.
AuthorsKelsey DR, Flanagan TD, Young JE, Yeagle PL
JournalVirology
PubMed ID1850923
'Hydrophobic di- and tripeptides which are capable of inhibiting enveloped virus infection of cells are also capable of inhibiting at least three different types of membrane fusion events. Large unilamellar vesicles (LUV) of N-methyl dioleoylphosphatidylethanolamine (N-methyl DOPE), containing encapsulated 1-aminonaphthalene-3,6,8-trisulfonic acid (ANTS) and/or p-xylene bis(pyridinium bromide) (DPX), were formed by ... More
Relative abundance of oligosaccharides in Candida species as determined by fluorophore-assisted carbohydrate electrophoresis.
AuthorsGoins TL, Cutler JE
JournalJ Clin Microbiol
PubMed ID10921940
'Fluorophore-assisted carbohydrate electrophoresis (FACE) is a straightforward, sensitive method for determining the presence and relative abundance of individual oligomannosyl residues in Candida mannoprotein, the major antigenic determinant located on the outer surface of the yeast cell wall. The single terminal aldehydes of oligomannosyl residues released by hydrolysis were tagged with ... More
Liposome fusion induced by a M(r) 18,000 protein localized to the acrosomal region of acrosome-reacted abalone spermatozoa.
AuthorsSwanson WJ, Vacquier VD
JournalBiochemistry
PubMed ID7578018
'A M(r) 18,000 protein is secreted by abalone spermatozoa during the acrosome reaction. Immunofluorescence of acrosome-reacted sperm localizes the protein as a coating on the spent acrosomal granule hull and on the surface of the acrosomal process. The membrane of the acrosomal process fuses with the egg plasma membrane at ... More
Interactions of cationic lipid vesicles with negatively charged phospholipid vesicles and biological membranes.
AuthorsStamatatos L, Leventis R, Zuckermann MJ, Silvius JR
JournalBiochemistry
PubMed ID3415963
'Lipid vesicles with a positive surface charge have been prepared by using mixtures of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) together with low mole fractions of a cationic lipid analogue, 1,2-bis(oleoyloxy)-3-(trimethylammonio)propane (DOTAP). We have used measurements of vesicle aggregation, lipid mixing, contents mixing, and contents leakage to examine the interactions between ... More
Quantitation of cation transport by reconstituted membrane vesicles containing purified acetylcholine receptor.
AuthorsWu WC, Moore HP, Raftery MA
JournalProc Natl Acad Sci U S A
PubMed ID6940146
'A stopped-flow spectroscopic technique was used to study the kinetics of ion transport by reconstituted membrane preparations containing purified acetylcholine receptor. Influx of thallium (I) into membrane vesicles was monitored as a decrease, due to quenching by the thallous ion, in the fluorescence of an entrapped fluorophore. In a reproducible ... More
Eserine and other tertiary amine interactions with Torpedo acetylcholine receptor postsynaptic membrane vesicles.
AuthorsKawai H, Carlson BJ, Okita DK, Raftery MA
JournalBiochemistry
PubMed ID9890891
'Interaction of the tertiary amines, arecolone, eserine (physostigmine), (+)-epibatidine, and (+/-)-epibatidine, with Torpedo nicotinic acetylcholine receptor-enriched membrane vesicles was investigated to characterize their action on the receptor, using stopped-flow thallium (I)-flux spectrofluorimetry. Arecolone, (+)-epibatidine, and (+/-)-epibatidine were agonists with activation constants of 390, 19, and 39 microM, respectively. Eserine was ... More
The analysis of fluorophore-labeled glycans by high-resolution polyacrylamide gel electrophoresis.
AuthorsJackson P
JournalAnal Biochem
PubMed ID8179179
'Many important biological processes are mediated by the carbohydrate moieties of glycoconjugates. Their structural determination presents considerable difficulties because of both their complex structures and the small quantities which are available from biological sources. In order to address some of the problems in this field a new method of glycan ... More
Bidirectional transepithelial water transport: measurement and governing mechanisms.
AuthorsPhillips JE, Wong LB, Yeates DB
JournalBiophys J
PubMed ID9929488
'In the search for the mechanisms whereby water is transported across biological membranes, we hypothesized that in the airways, the hydration of the periciliary fluid layer is regulated by luminal-to-basolateral water transport coupled to active transepithelial sodium transport. The luminal-to-basolateral (JWL-->B) and the basolateral-to-luminal (JWB-->L) transepithelial water fluxes across ovine ... More
Liposome fusion catalytically induced by phospholipase C.
AuthorsNieva JL, Goñi FM, Alonso A
JournalBiochemistry
PubMed ID2819074
'Large unilamellar vesicles composed of phosphatidylcholine/phosphatidylethanolamine/cholesterol (50:25:25 mole ratio) were treated with phospholipase C. The early stages of phospholipid cleavage are accompanied by mixing of bilayer lipids (monitored by dequenching of octadecylrhodamine fluorescence) and leakage-free mixing of vesicle contents [measured by using 8-aminonaphthalene-1,3,6-trisulfonic acid (ANTS) and p-xylylenebis(pyridinium bromide) (DPX)]. These ... More
pH-dependent fusion of phosphatidylcholine small vesicles. Induction by a synthetic amphipathic peptide.
AuthorsParente RA, Nir S, Szoka FC
JournalJ Biol Chem
PubMed ID2450874
'A synthetic, amphipathic 30-amino acid peptide with the major repeat unit Glu-Ala-Leu-Ala (GALA) was designed to mimic the behavior of the fusogenic sequences of viral fusion proteins. GALA is a water-soluble peptide with an aperiodic conformation at neutral pH and becomes an amphipathic alpha-helix as the pH is lowered to ... More
Activation and desensitization of Torpedo acetylcholine receptor: evidence for separate binding sites.
AuthorsDunn SM, Raftery MA
JournalProc Natl Acad Sci U S A
PubMed ID6960348
'The acetylcholine receptor from Torpedo californica was labeled by reaction with the fluorescent probe 4-[N-(iodoacetoxy)ethyl-N-methyl]amino-7-nitrobenz-2-oxa-1,3-diazole without apparent effect on its in vitro ligand binding and functional properties. Addition of acetylcholine or carbamoylcholine to the labeled-receptor preparations enhanced the fluorescence of the bound probe, and this effect was specific for agonists ... More
The polar region consecutive to the HIV fusion peptide participates in membrane fusion.
AuthorsPeisajovich SG, Epand RF, Pritsker M, Shai Y, Epand RM
JournalBiochemistry
PubMed ID10677233
'The fusion peptide of HIV-1 gp41 is formed by the 16 N-terminal residues of the protein. This 16-amino acid peptide, in common with several other viral fusion peptides, caused a reduction in the bilayer to hexagonal phase transition temperature of dipalmitoleoylphosphatidylethanolamine (T(H)), suggesting its ability to promote negative curvature in ... More
The concentration-dependent membrane activity of cecropin A.
'Cecropin A is a naturally occurring, linear, cationic, 37-residue antimicrobial peptide. The precise mechanism by which it kills bacteria is not known, but its site of action is believed to be the cell membrane. To investigate the nature of its membrane activity, we examined the ability of cecropin A to ... More
"De novo" design of peptides with specific lipid-binding properties.
AuthorsLins L, Charloteaux B, Heinen C, Thomas A, Brasseur R
JournalBiophys J
PubMed ID16275638
'In this study, we describe an in silico method to design peptides that can be made of non-natural amino acids and elicit specific membrane-interacting properties. The originality of the method holds in the capacities developed to design peptides from any non-natural amino acids as easily as from natural ones, and ... More
Synexin enhances the aggregation rate but not the fusion rate of liposomes.
AuthorsMeers P, Bentz J, Alford D, Nir S, Papahadjopoulos D, Hong K
JournalBiochemistry
PubMed ID2971392
'The effect of synexin on the calcium-induced fusion of large unilamellar liposomes was studied by using two assays for the mixing of aqueous contents. The results were analyzed in terms of the mass action kinetic model, which describes the overall fusion reaction as a two-step sequence consisting of a second-order ... More
Resolution of the branched forms of oligosaccharides by high-performance capillary electrophoresis.
AuthorsStefansson M, Novotny M
JournalCarbohydr Res
PubMed ID8039171
'The heterogeneous nature of most polysaccharides found in nature includes distribution in molecular weight, primary sequence, and branching. The analytical methodology used in the characterization of these structural aspects must ensure high separation efficiency and selectivity. This paper reports on the high-performance capillary electrophoresis (HPCE) separation of branched forms of ... More
Mode of membrane interaction and fusogenic properties of a de novo transmembrane model peptide depend on the length of the hydrophobic core.
AuthorsLorin A, Charloteaux B, Fridmann-Sirkis Y, Thomas A, Shai Y, Brasseur R
JournalJ Biol Chem
PubMed ID17459883
'Model peptides composed of alanine and leucine residues are often used to mimic single helical transmembrane domains. Many studies have been carried out to determine how they interact with membranes. However, few studies have investigated their lipid-destabilizing effect. We designed three peptides designated KALRs containing a hydrophobic stretch of 14, ... More
Interaction of earthworm hemolysin with lipid membranes requires sphingolipids.
AuthorsLange S, Nüssler F, Kauschke E, Lutsch G, Cooper EL, Herrmann A
JournalJ Biol Chem
PubMed ID9252415
'Lytic activity in the coelomic fluid of earthworm (Eisenia fetida fetida) has been ascribed to eiseniapore, a hemolytic protein of 38 kDa. Since receptors for eiseniapore on target cell membranes are not known, we used lipid vesicles of various composition to determine whether specific lipids may serve as receptors. Lytic ... More
Viroporin-mediated membrane permeabilization. Pore formation by nonstructural poliovirus 2B protein.
AuthorsAgirre A, Barco A, Carrasco L, Nieva JL
JournalJ Biol Chem
PubMed ID12183456
'Enterovirus nonstructural 2B protein is involved in cell membrane permeabilization during late viral infection. Here we analyze the pore forming activity of poliovirus 2B and several of its variants. Solubilization of 2B protein was achieved by generating a fusion protein comprised of poliovirus 2B attached to a maltose-binding protein (MBP) ... More
Evolution of lipidic structures during model membrane fusion and the relation of this process to cell membrane fusion.
AuthorsLee J, Lentz BR
JournalBiochemistry
PubMed ID9174340
'The sequence of events involved in poly(ethylene glycol)-mediated fusion of small unilamellar vesicles (SUVs) has been studied. Fusion events were monitored using light scattering for vesicle aggregation, the fluorescence lifetime of membrane probe lipids (DPHpPC and NBD-PS) for membrane mixing, the aqueous fluorescent marker (Tb3+/DPA and H+/HPTS) for contents mixing; ... More
Fluorescence assays to monitor membrane fusion: potential application in biliary lipid secretion and vesicle interactions.
AuthorsHoekstra D
JournalHepatology
PubMed ID2210660
'Membrane fusion constitutes an essential, intermediate step in numerous cell biological processes, occurring for example during endocytosis, membrane recycling and exocytosis. Also less desirable events such as the infection of cells by animal viruses are mediated by membrane fusion during which the viral envelope merges with a cellular membrane, causing ... More
Functional signal peptide reduces bilayer thickness of phosphatidylcholine liposomes.
AuthorsTahara Y, Murata M, Ohnishi S, Fujiyoshi Y, Kikuchi M, Yamamoto Y
JournalBiochemistry
PubMed ID1390661
'To investigate the interaction between a signal peptide and the lipid bilayer, two kinds of peptides, L8-M5 (L8 = MRL8PLAALG, M5 = KVFER) and L14-M5 (L14 = MRL14PLAALG), were examined in membranes composed of dioleoylphosphatidylcholine (DOPC). Peptides L8 and L14 are artificially designed signal sequences, and M5 is the N-terminal ... More
Effect of cholesterol and charge on pore formation in bilayer vesicles by a pH-sensitive peptide.
AuthorsNicol F, Nir S, Szoka FC
JournalBiophys J
PubMed ID8968598
'The effect of cholesterol on the bilayer partitioning of the peptide GALA (WEAALAEALAEALAEHLAEALAEALEALAA) and its assembly into a pore in large unilamellar vesicles composed of neutral and negatively charged phospholipids has been determined. GALA undergoes a conformational change from a random coil to an amphipathic alpha-helix when the pH is ... More
Photoinduced destabilization of liposomes.
AuthorsLamparski H, Liman U, Barry JA, Frankel DA, Ramaswami V, Brown MF, O'Brien DF
JournalBiochemistry
PubMed ID1731924
'The stability of two-component liposomes composed of the polymerizable 1,2-bis-[10-(2'',4''-hexadienoyloxy)decanoyl]-sn-glycero-3-phosphati dylcholine (SorbPC) and either a phosphatidylethanolamine (PE) or a phosphatidylcholine (PC) were examined via fluorescence leakage assays. Ultraviolet light exposure of SorbPC-containing liposomes forms poly-SorbPC, which phase separates from the remaining monomeric lipids. If the nonpolymerizable lipids are PE''s, then ... More
Separate sites of low and high affinity for agonists on Torpedo californica acetylcholine receptor.
AuthorsDunn SM, Conti-Tronconi BM, Raftery MA
JournalBiochemistry
PubMed ID6860645
'We have studied alkylation of the membrane-bound acetylcholine receptor (AcChR) from Torpedo californica electric organ by the cholinergic agonist bromo-acetylcholine (BrAcCh). Following reduction of the AcChR with dithiothreitol (DTT) under strictly controlled conditions, a single class of binding sites was covalently labeled by BrAcCh. The extent of alkylation was dependent ... More
Membrane insertion of Escherichia coli alpha-hemolysin is independent from membrane lysis.
AuthorsSánchez-Magraner L, Cortajarena AL, Goñi FM, Ostolaza H
JournalJ Biol Chem
PubMed ID16377616
'Escherichia coli alpha-hemolysin (HlyA) is a protein exotoxin that binds and lyses eukaryotic cell and model membranes in the presence of calcium. Previous studies have been able to distinguish between reversible toxin binding to the membrane and irreversible insertion into the lipid matrix. Membrane lysis occurs as the combined effect ... More
Nonperturbing fluorescent labeling of polysaccharides.
AuthorsMeunier F, Wilkinson KJ
JournalBiomacromolecules
PubMed ID12099834
'A fluorescent labeling procedure, which does not perturb macromolecular conformations, was employed to bind a rhodamine derivative to the reducing end of several water-soluble polysaccharides by reductive amination in the presence of sodium cyanoborohydride. Fluorescence correlation spectroscopy, atomic force microscopy, and size exclusion chromatography were used to demonstrate that the ... More
Analysis of glycosphingolipids by fluorophore-assisted carbohydrate electrophoresis using ceramide glycanase from Mercenaria mercenaria.
AuthorsBasu SS, Dastgheib-Hosseini S, Hoover G, Li Z, Basu S
JournalAnal Biochem
PubMed ID7856860
'Polyacrylamide gel electrophoresis of fluorophore-labeled saccharides is a simple and sensitive separation method for glycan analysis. This method requires an aldehydic reducing carbon on the saccharide in order to react with the amine group of the fluorophore (8-aminonaphthalene-1,3,6-trisulfonic acid or 2-aminoacridone). We have used exoglycosidase-free ceramide glycanase from hard-shelled clam ... More
Fusion between retinal rod outer segment membranes and model membranes: a role for photoreceptor peripherin/rds.
AuthorsBoesze-Battaglia K, Lamba OP, Napoli AA, Sinha S, Guo Y
JournalBiochemistry
PubMed ID9649331
'Peripherin/rds plays an essential role in the maintenance of photoreceptor rod cell disk membrane structure. The purification of this protein to homogeneity [Boesze-Battaglia, K., et al. (1997) Biochemistry 36, 6835-6846] has allowed us to characterize the functional role of peripherin/rds in the maintenance of rod outer segment (ROS) membrane fusion ... More
Interactions of the low molecular weight group of surfactant-associated proteins (SP 5-18) with pulmonary surfactant lipids.
AuthorsShiffer K, Hawgood S, Düzgünes N, Goerke J
JournalBiochemistry
PubMed ID3401444
'The interaction of the low molecular weight group of surfactant-associated proteins, SP 5-18, with the major phospholipids of pulmonary surfactant was studied by fluorescence measurements of liposomal permeability and fusion, morphological studies, and surface activity measurements. The ability of SP 5-18 to increase the permeability of large unilamellar lipid vesicles ... More
Separation of complex oligosaccharide mixtures by capillary electrophoresis in the open-tubular format.
AuthorsStefansson M, Novotny M
JournalAnal Chem
PubMed ID7512804
'The fluorescent derivatives of complex oligosaccharide mixtures from different origins are separated in open capillaries. The number of negatively charged sulfonate groups in the tag molecule strongly affects separation efficiency and selectivity. Coating of the capillary surface with linear polyacrylamide has been essential to ensure fast and stable migration velocities. ... More
The glycosylation of IgA produced by murine B cells is altered by Th2 cytokines.
AuthorsChintalacharuvu SR, Emancipator SN
JournalJ Immunol
PubMed ID9278322
'We sought to determine whether selected cytokines, known to profoundly increase proliferation and/or production of Ig by B cells and their progeny, also have as yet unrecognized effects upon IgA glycosylation. For these studies, we selected CH12LX mouse B lymphoma cells, a widely used model of B cell differentiation. Glycosylation ... More
Electrophoretic methods for the analysis of N-linked oligosaccharides.
AuthorsRaju TS
JournalAnal Biochem
PubMed ID10906231
Electrophoresis for the analysis of acidic oligosaccharides.
AuthorsKoketsu M, Linhardt RJ
JournalAnal Biochem
PubMed ID10906233
High-resolution polyacrylamide gel electrophoresis of fluorophore-labeled reducing saccharides.
AuthorsJackson P
JournalMethods Enzymol
PubMed ID8139500
High-sensitivity and high-resolution methods for glycoprotein analysis.
AuthorsAnumula KR
JournalAnal Biochem
PubMed ID10929803
Metabolic cytometry: monitoring oligosaccharide biosynthesis in single cells by capillary electrophoresis.
AuthorsKrylov SN, Arriaga EA, Chan NW, Dovichi NJ, Palcic MM
JournalAnal Biochem
PubMed ID10906232
Recent advances in capillary electrophoresis of carbohydrates.
AuthorsEl Rassi Z, Mechref Y
JournalElectrophoresis
PubMed ID8900934
Optical methods to measure membrane transport processes.
AuthorsVerkman AS
JournalJ Membr Biol
PubMed ID8606370
Fluorescent staining of glycoproteins on polyvinylidene difluoride membrane with 8-aminonaphthalene-1,3,6-trisulfonate.
AuthorsChe FY, Song JF, Yu LR, Wang KY, Xia QC
JournalBiotechniques
PubMed ID11414218
Here, we describe a simple and sensitive method that allows fluorescent detection of glycoproteins on polyvinylidene difluoride (PVDF) membrane. We used periodic acid oxidation of carbohydrate chains of glycoproteins and fluorescent labeling with 8-aminonaphthalene-1,3,6-trisulfonate (AN-TS) by reductive amination. We developed an additional method to enhance the ability of PVDF to ... More
Abscisic acid enhances aggregation and fusion of phospholipid vesicles.
AuthorsStillwell W, Brengle B, Wassall SR
JournalBiochem Biophys Res Commun
PubMed ID2972286
The plant hormone abscisic acid (ABA) is shown to enhance the aggregation and fusion of small unilamellar lipid vesicles composed of 80 mol% dimyristoylphosphatidylcholine (DMPC) and 20 mol% dimyristoylphosphatidylcholine (DMPE). Aggregation and fusion did not occur with single component (100 mol%) DMPC vesicles. Fusion was followed by two fundamentally different ... More
Continuous monitoring of transport by fluorescence on cells and vesicles.
AuthorsEidelman O, Cabantchik ZI
JournalBiochim Biophys Acta
PubMed ID2686755
Fluorescence techniques are gaining wider applicability in the field of membrane transport due to their high temporal resolution, modest demand for biological material and the kinetic information which is made available by fluorescence tracings. The development of novel fluorescent substrates for particular transport systems and of novel fluorescent indicators for ... More
A simple fluorescent method to determine complement-mediated liposome immune lysis.
AuthorsSmolarsky M, Teitelbaum D, Sela M, Gitler C
JournalJ Immunol Methods
PubMed ID323363
A simple inexpective method is described to study the kinetics of complement-mediated immune lysis of liposomes containing sheep red blood cell lipid antigens. It is based on the fact that trapping the fluorescent molecule 1-aminonaphthalene-3,6,8-trisulfonate and the dynamic quencher, alpha, alpha'-dipyridinium p-xylene dibromide within the liposome inner volume results in ... More
Calcium buffering capacity of neuronal cell cytosol measured by flash photolysis of calcium buffer NP-EGTA.
AuthorsFleet A, Ellis-Davies G, Bolsover S
JournalBiochem Biophys Res Commun
PubMed ID9784424
N1E-115 mouse neuroblastoma cells were injected with a calcium buffer/indicator solution to allow both ratiometric measurement of free calcium concentration and the release of calcium ions upon UV flash. The solution contained sulforhodamine, a marker dye used to estimate the volume injected; fluo-3, a calcium indicator, and NP-EGTA, a high ... More
Micropipette manipulation technique for the monitoring of pH-dependent membrane lysis as induced by the fusion peptide of influenza virus.
AuthorsSoltesz SA, Hammer DA
JournalBiophys J
PubMed ID7711257
We have assembled a micropipette aspiration assay to measure membrane destabilization events in which large (20-30 microns diameter) unilamellar vesicles are manipulated and exposed to membrane destabilizing agents. Single events can be seen with a light microscope and are recorded using both a video camera and a photomultiplier tube. We ... More
Detection of carbohydrates in capillary electrophoresis.
AuthorsPaulus A, Klockow A
JournalJ Chromatogr A
PubMed ID8601201
This review focuses on recent developments in sensitive detection modes for carbohydrates after separation by capillary electrophoretic methods. To bring detection sensitivity for carbohydrates analysis in line with current methods in protein sequencing, concentration detection limits of 10(-6) molar or better are required. A discussion of mass detection limits and ... More
Lectin affinity electrophoresis for the separation of fluorescently labeled sugar derivatives.
AuthorsLee KB, Kim YS, Linhardt RJ
JournalAnal Biochem
PubMed ID1416018
Lectin affinity electrophoresis was applied to the separation of charged, fluorescent conjugates of disaccharides. Four fluorescent conjugates were prepared by reductive amination of alpha-D-Man-(1----3)-D-Man, alpha-D-Gal-(1----4)-D-Glc, alpha-D-Gal-(1----6)-D-Glc, and beta-D-Gal-(1----4)-D-Glc in the presence of 7-amino-1,3-naphthalenedisulfonic acid. These charged fluorescent-disaccharide conjugates all have identical molecular weight and in the absence of conconavalin A ... More
Transmembrane pores formed by synthetic p-octiphenyl beta-barrels with internal carboxylate clusters: regulation of ion transport by pH and Mg(2+)- complexed 8-aminonaphthalene-1,3,6-trisulfonate.
AuthorsDas G, Matile S
JournalProc Natl Acad Sci U S A
PubMed ID11891277
Design, synthesis, and study of a synthetic barrel-stave supramolecule with p-octiphenyl "staves," beta-sheet "hoops," and hydrophobic exterior as well as internal carboxylate clusters are reported. Ion transport experiments indicate the formation of transmembrane pores at 5 < pH < 7 with nanomolar activity. Blockage of dye efflux from spherical bilayers ... More
Sizing membrane pores in lipid vesicles by leakage of co-encapsulated markers: pore formation by melittin.
AuthorsLadokhin AS, Selsted ME, White SH
JournalBiophys J
PubMed ID9083680
Many toxins and antimicrobial peptides permeabilize membrane vesicles by forming multimeric pores. Determination of the size of such pores is an important first step for understanding their structure and the mechanism of their self-assembly. We report a simple method for sizing pores in vesicles based on the differential release of ... More
End-label, free-solution capillary electrophoresis of highly charged oligosaccharides.
AuthorsSudor J, Novotny MV
JournalAnal Chem
PubMed ID8633768
The effect of fluorescent tags on the separation of negatively charged oligosaccharides, derived from a partially hydrolyzed kappa-carrageenan, was studied. When the charge-to-friction ratio of oligosaccharides is increased by the end-label, the migration order is from smaller to larger oligomers, and the resolution of larger oligomers could be improved by ... More
Electrophoretic resolution and fluorescence detection of N-linked glycoprotein oligosaccharides after reductive amination with 8-aminonaphthalene-1,3,6-trisulphonic acid.
AuthorsStack RJ, Sullivan MT
JournalGlycobiology
PubMed ID1372525
The relative mobilities of various N-linked oligosaccharides reductively aminated to the charged fluorophore 8-amino-naphthalene-1,3,6-trisulphonic acid (ANTS) were determined by electrophoresis on high-density polyacrylamide slab gels. Each ANTS-derivatized oligosaccharide was assigned a relative migration index (RMI) expressed in terms of glucose equivalents, which was conveniently estimated by reference to a homologous ... More
Pardaxin induces aggregation but not fusion of phosphatidylserine vesicles.
AuthorsLelkes PI, Lazarovici P
JournalFEBS Lett
PubMed ID2450781
The effects on membranes of pardaxin, an amphipathic polypeptide, purified from the gland secretion of the Red Sea Moses sole flatfish Pardachirus marmoratus are dose-dependent and range from formation of voltage-gated, cation-selective pores to lysis. We have now investigated the interactions of pardaxin with small unilamellar liposomes. Light scattering showed ... More
Polyacrylamide gel electrophoresis of reducing saccharides labeled with the fluorophore 8-aminonaphthalene-1,3,6-trisulphonic acid: application to the enzymological structural analysis of oligosaccharides.
AuthorsJackson P, Williams GR
JournalElectrophoresis
PubMed ID1904815
Mono- and oligosaccharides, each containing a reducing end group, were labeled with the charged fluorophore 8-aminonaphthalene-1,3,6-trisulphonic acid and the resulting derivatives were separated with high resolution by polyacrylamide gel electrophoresis using a method developed recently (P. Jackson, Biochem. J. 1990, 270, 705-713) but with an alternative electrophoretic buffer system. The ... More
Polysaccharide analysis using carbohydrate gel electrophoresis: a method to study plant cell wall polysaccharides and polysaccharide hydrolases.
AuthorsGoubet F, Jackson P, Deery MJ, Dupree P
JournalAnal Biochem
PubMed ID11743692
A method to characterize plant cell wall polysaccharides is presented. The complexity of the polymer structures and the large number of different charged and uncharged monosaccharides that make up plant polysaccharides have previously made analysis technically demanding and laborious. Polysaccharide analysis using carbohydrate gel electrophoresis (PACE) relies on derivatization of ... More
Design, synthesis, and characterization of a cationic peptide that binds to nucleic acids and permeabilizes bilayers.
AuthorsWyman TB, Nicol F, Zelphati O, Scaria PV, Plank C, Szoka FC
JournalBiochemistry
PubMed ID9062132
We have designed a cationic amphipathic peptide, KALA (WEAKLAKALAKALAKHLAKALAKALKACEA), that binds to DNA, destabilizes membranes, and mediates DNA transfection. KALA undergoes a pH-dependent random coil to amphipathic alpha-helical conformational change as the pH is increased from 5.0 to 7.5. One face displays hydrophobic leucine residues, and the opposite face displays ... More
Inhibition of membrane fusion by lysophosphatidylcholine.
AuthorsYeagle PL, Smith FT, Young JE, Flanagan TD
JournalBiochemistry
PubMed ID8110784
The ability of lysophosphatidylcholine to inhibit membrane fusion at subsolubilizing concentrations (between 1 and 9 mol % with respect to the membrane lipids) was examined. Fusion between N-methyldioleoylphosphatidylethanolamine (DOPE) large unilamellar vesicles (LUV) and fusion between Sendai virus and N-methyl-DOPE LUV were measured. A contents mixing fusion assay was used ... More
The membrane-active regions of the hepatitis C virus E1 and E2 envelope glycoproteins.
AuthorsPérez-Berna AJ, Moreno MR, Guillén J, Bernabeu A, Villalaín J
JournalBiochemistry
PubMed ID16533059
We have identified the membrane-active regions of the full sequences of the HCV E1 and E2 envelope glycoproteins by performing an exhaustive study of membrane leakage, hemifusion, and fusion induced by 18-mer peptide libraries on model membranes having different phospholipid compositions. The data and their comparison have led us to ... More
Direct spectroscopic studies of cation translocation by Torpedo acetylcholine receptor on a time scale of physiological relevance.
AuthorsMoore HP, Raftery MA
JournalProc Natl Acad Sci U S A
PubMed ID6933499
The kinetics of carbamoylcholine-mediated cation transport across the membrane of vesicles containing acetylcholine receptor have been measured on the physiologically relevant time scale of a few milliseconds. The stopped-flow spectroscopic approach utilizes thallium(I) as the cation transported into sealed vesicles containing a water-soluble fluorophore. Upon entry of thallium(I), fluorescence quenching ... More
Structure and interaction with membrane model systems of a peptide derived from the major epitope region of HIV protein gp41: implications on viral fusion mechanism.
The HIV-1 gp41 envelope protein mediates entry of the virus into the target cell by promoting membrane fusion. With a view toward possible new insights into viral fusion mechanisms, we have investigated by infrared, fluorescence, and nuclear magnetic resonance spectroscopies and calorimetry a fragment of 19 amino acids corresponding to ... More
Carbohydrate chromatography: towards yoctomole sensitivity.
AuthorsDavies MJ, Hounsell EF
JournalBiomed Chromatogr
PubMed ID8949909
In attempting to analyse complex carbohydrates by HPLC or capillary electrophoresis (CE) the chromatographer is faced with many challenges. The diversity of oligosaccharide structures described the date and their poor resolution on many chromatographic systems present a significant challenge to the chromatographer. In addition to this, the non-chromogenic nature of ... More
Time-resolved and equilibrium measurements of the effects of poly(ethylene glycol) on small unilamellar phospholipid vesicles.
AuthorsViguera AR, Mencía M, Goñi FM
JournalBiochemistry
PubMed ID8466910
The effects of poly(ethylene glycol) (PEG) on sonicated unilamellar vesicles made of phosphatidylcholine have been examined. Stopped-flow and equilibrium data are presented for vesicle aggregation, vesicle leakage, lipid mixing, and aqueous contents mixing. Vesicle aggregation is detected as a monoexponential increase in light scattering, for PEG concentrations between 5 and ... More
Recovery of free oligosaccharides from derivatives labeled by reductive amination.
AuthorsSuzuki S, Fujimori T, Yodoshi M
JournalAnal Biochem
PubMed ID16701074
This study examined chemical regeneration of free oligosaccharides from their fluorescent derivatives prepared by reductive amination with various aromatic amines. Maltose derivatives of ethyl 4-aminobenzoate (p-ABEE), 2-aminobenzonitrile (o-ABN), 4-aminobenzonitrile (p-ABN), 7-amino-4-methylcoumarin (AMC), 2-aminobenzoic acid (o-ABA), 2-aminobenzamide (o-ABAD), 2-aminopyridine (AP), and 8-aminonaphthalene-1,3,6-trisulfonate (ANTS) were incubated at 30 degrees C with an ... More
Capillary gel electrophoresis separation of high-mannose type oligosaccharides derivatized by 1-aminopyrene-3,6,8-trisulfonic acid.
AuthorsGuttman A, Pritchett T
JournalElectrophoresis
PubMed ID8586063
In this paper we report the capillary gel electrophoresis separation of 1-aminopyrene-3,6,8-trisulfonic acid (APTS) labeled oligosaccharides, released enzymatically from bovine pancreatic ribonuclease B. The released and labeled high-mannose structures were identified by spiking the separated peaks with the appropriate commercially available individual oligosaccharides. Baseline separation of the three positional isomers ... More