Lanthanide ions as luminescent probes of biomolecular structure.
AuthorsO'Hara PB
JournalPhotochem Photobiol
PubMed ID2964040
Fusion of liposomes and rat brain microsomes examined by two assays.
AuthorsCorazzi L, Fratto G, Pistolesi R, Arienti G
JournalJ Membr Biol
PubMed ID2621744
'Liposomes are prepared from rat brain microsomal lipid and loaded with either Tb3+ or dipicolinic acid (DPA) to test fusion with the Tb-DPA assay. They are also loaded with octadecyl Rhodamine B chloride (R18) to test fusion with the R18 assay. The addition of either Ca2+ or Mg2+ to loaded ... More
Mass action kinetics of phosphatidylserine vesicle fusion as monitored by coalescence of internal vesicle volumes.
AuthorsNir S, Bentz J, Wilschut J
JournalBiochemistry
PubMed ID7470447
'The kinetics of Ca2+-induced fusion of sonicated phosphatidylserine vesicles is analyzed by means of the mass action model. The results of calculations are shown to simulate the experimental results for the mixing of aqueous vesicle volumes, release of vesicle contents and for the observed increase in light scattering [Wilschut, J., ... More
Conformation of apolipoprotein AI in reconstituted lipoprotein particles and particle-membrane interaction: effect of cholesterol.
AuthorsTricerri A, Córsico B, Toledo JD, Garda HA, Brenner RR
JournalBiochim Biophys Acta
PubMed ID9518555
'Discoidal recombinant high density lipoproteins (rHDL) of apolipoprotein AI (apoAI) and palmitoyloleoylphosphatidylcholine (POPC), with or without cholesterol, were prepared by cholate dialysis. By gel filtration, rHDL containing 2-4 (Lp2, Lp3 and Lp4) apoAI molecules/particle were obtained. The ApoAI conformation in these rHDL was investigated by tryptophan fluorescence, denaturation with guanidine ... More
Characterization of lanthanide ion binding to the EF-hand protein S100 beta by luminescence spectroscopy.
AuthorsChaudhuri D, Horrocks WD, Amburgey JC, Weber DJ
JournalBiochemistry
PubMed ID9245399
'S100 beta is a member of a group of low-molecular weight acidic calcium binding proteins widely distributed in the vertebrate nervous system containing two helix-loop-helix calcium binding motifs (sites I and II). In addition, S100 beta also has auxiliary Zn2+ binding sites that are distinct from the Ca2+ binding sites. ... More
Osmotic and curvature stress affect PEG-induced fusion of lipid vesicles but not mixing of their lipids.
AuthorsMalinin VS, Frederik P, Lentz BR
JournalBiophys J
PubMed ID11916865
'Poly (ethylene glycol) (PEG) in the external environment of membrane vesicles creates osmotic imbalance that leads to mechanical stress in membranes and may induce local membrane curvature. To determine the relative importance of membrane stress and curvature in promoting fusion, we monitored contents mixing (CM) and lipid mixing (LM) between ... More
Fusion of small unilamellar liposomes with phospholipid planar bilayer membranes and large single-bilayer vesicles.
AuthorsDüzgünes N, Ohki S
JournalBiochim Biophys Acta
PubMed ID6163458
'Small unilamellar phosphatidylserine/phosphatidylcholine liposomes incubated on one side of planar phosphatidylserine bilayer membranes induced fluctuations and a sharp increase in the membrane conductance when the Ca2+ concentration was increased to a threshold of 3--5 mM in 100 mM NaCl, pH 7.4. Under the same ionic conditions, these liposomes fused with ... More
A domain of membrane-bound blood coagulation factor Va is located far from the phospholipid surface. A fluorescence energy transfer measurement.
AuthorsIsaacs BS, Husten EJ, Esmon CT, Johnson AE
JournalBiochemistry
PubMed ID3768326
'The larger subunit of blood coagulation factor Va was covalently labeled with iodoacetamido derivatives of fluorescein and rhodamine without loss of functional activity, as measured by either the one-stage clotting assay or the ability to accelerate prothrombin activation in a purified system. The spectral properties of the dyes were not ... More
Luminescence resonance energy transfer measurements in myosin.
AuthorsBurmeister Getz E, Cooke R, Selvin PR
JournalBiophys J
PubMed ID9591671
'Myosin is thought to generate force by a rotation between the relative orientations of two domains. Direct measurements of distances between the domains could potentially confirm and quantify these conformational changes, but efforts have been hampered by the large distances involved. Here we show that luminescence resonance energy transfer (LRET), ... More
Evidence of a calcium-induced structural change in the ATP-binding site of the sarcoplasmic-reticulum Ca2+-ATPase using terbium formycin triphosphate as an analogue of Mg-ATP.
AuthorsGirardet JL, Dupont Y, Lacapere JJ
JournalEur J Biochem
PubMed ID2528452
'Terbium ions and terbium formycin triphosphate have been used to investigate the interactions between the cation and nucleotide binding sites of the sarcoplasmic reticulum Ca2+-ATPase. Three classes of Tb3+-binding sites have been found: a first class of low-affinity (Kd = 10 microM) corresponds to magnesium binding sites, located near a ... More
A study of sensitized lanthanide luminescence in an engineered calcium-binding protein.
AuthorsClark ID, MacManus JP, Banville D, Szabo AG
JournalAnal Biochem
PubMed ID8489002
'In this study, the CD loop of the Ca(2+)-binding protein oncomodulin was replaced by a high-affinity, metal-binding sequence that was found to reverse the order of fill of the two sites in the protein. A cysteine was included at position 7 of this sequence, i.e., DKNADGCIEFEE. The cysteine allowed covalent ... More
Factors governing the assembly of cationic phospholipid-DNA complexes.
AuthorsKennedy MT, Pozharski EV, Rakhmanova VA, MacDonald RC
JournalBiophys J
PubMed ID10692346
'The interaction of DNA with a novel cationic phospholipid transfection reagent, 1,2-dioleoyl-sn-glycero-3-ethylphosphocholine (EDOPC), was investigated by monitoring thermal effects, particle size, vesicle rupture, and lipid mixing. By isothermal titration calorimetry, the heat of interaction between large unilamellar EDOPC vesicles and plasmid DNA was endothermic at both physiological and low ionic ... More
An actin-dependent conformational change in myosin.
AuthorsXiao M, Reifenberger JG, Wells AL, Baldacchino C, Chen LQ, Ge P, Sweeney HL, Selvin PR
JournalNat Struct Biol
PubMed ID12679807
'Conformational changes within myosin lead to its movement relative to an actin filament. Several crystal structures exist for myosin bound to various nucleotides, but none with bound actin. Therefore, the effect of actin on the structure of myosin is poorly understood. Here we show that the swing of smooth muscle ... More
A protein containing a serine-rich domain with vesicle fusing properties mediates cell cycle-dependent cytosolic pH regulation.
AuthorsBrazill DT, Caprette DR, Myler HA, Hatton RD, Ammann RR, Lindsey DF, Brock DA, Gomer RH
JournalJ Biol Chem
PubMed ID10747962
'Initial differentiation in Dictyostelium involves both asymmetric cell division and a cell cycle-dependent mechanism. We previously identified a gene, rtoA, which when disrupted randomizes the cell cycle-dependent mechanism without affecting either the underlying cell cycle or asymmetric differentiation. We find that in wild-type cells, RtoA levels vary during the cell ... More
Comparison of simulated and measured calcium sparks in intact skeletal muscle fibers of the frog.
AuthorsBaylor SM, Hollingworth S, Chandler WK
JournalJ Gen Physiol
PubMed ID12198091
'Calcium sparks in frog intact skeletal muscle fibers were modeled as stereotypical events that arise from a constant efflux of Ca(2+) from a point source for a fixed period of time (e.g., 2.5 pA of Ca(2+) current for 4.6 ms; 18 degrees C). The model calculates the local changes in ... More
Fluorescent probes for measuring the binding constants and distances between the metal ions bound to Escherichia coli glutamine synthetase.
AuthorsLin WY, Eads CD, Villafranca JJ
JournalBiochemistry
PubMed ID1672822
'TNS, 2-p-toluidinylnaphthalene-6-sulfonate, has been used as a fluorescent probe to determine the binding constants of metal ions to the two binding sites of Escherichia coli glutamine synthetase (GS). TNS fluorescence is enhanced dramatically when bound to proteins due to its high quantum yield resulting from its interactions with hydrophobic regions ... More
Characterization of cation-binding sequences in the platelet integrin GPIIb-IIIa (alpha IIb beta 3) by terbium luminescence.
AuthorsCierniewski CS, Haas TA, Smith JW, Plow EF
JournalBiochemistry
PubMed ID7522557
'The binding of cations to purified GPIIb-IIIa (alpha IIb beta 3) and synthetic peptides corresponding to the potential cation-binding sites within this integrin has been assessed by terbium luminescence spectroscopy. Tb3+ supported fibrinogen binding to purified GPIIb-IIIa, at lower concentrations than Ca2+, consistent with its higher affinity for cation-binding motifs. ... More
Lipid mixing during membrane aggregation and fusion: why fusion assays disagree.
AuthorsDüzgünes N, Allen TM, Fedor J, Papahadjopoulos D
JournalBiochemistry
PubMed ID3442666
'The kinetics of lipid mixing during membrane aggregation and fusion was monitored by two assays employing resonance energy transfer between N-(7-nitro-2,1,3-benzoxadiazol-4-yl)phosphatidylethanolamine (NBD-PE) and N-(lissamine Rhodamine B sulfonyl)phosphatidylethanolamine (Rh-PE). For the "probe mixing" assay, NBD-PE and Rh-PE were incorporated into separate populations of phospholipid vesicles. For the "probe dilution" assay, both ... More
Interaction and fusion of unilamellar vesicles containing cerebrosides and sulfatides induced by myelin basic protein.
AuthorsMaggio B, Yu RK
JournalChem Phys Lipids
PubMed ID2480186
'The effects of myelin basic protein on the aggregation, lipid bilayer merging, intercommunication of aqueous compartments and leakage of small unilamellar vesicles of egg phosphatidylcholine containing different proportions of galactocerebroside and sulfatide were investigated. This was performed employing light scattering, absorbance changes and fluorescence assays (resonance energy transfer, Terbium/dipicolinic acid ... More
Plasmenylethanolamine facilitates rapid membrane fusion: a stopped-flow kinetic investigation correlating the propensity of a major plasma membrane constituent to adopt an HII phase with its ability to promote membrane fusion.
AuthorsGlaser PE, Gross RW
JournalBiochemistry
PubMed ID8180209
'A critical step in membrane fusion involves the formation of a lipid intermediate which shares a conformational similarity with an inverted hexagonal phase (HII). Since plasmenylethanolamines possess a marked propensity for hexagonal phase formation and represent a major lipid constituent of several membrane systems which undergo rapid membrane fusion (e.g., ... More
Ca2+-induced fusion of phosphatidylserine vesicles: mass action kinetic analysis of membrane lipid mixing and aqueous contents mixing.
AuthorsWilschut J, Scholma J, Bental M, Hoekstra D, Nir S
JournalBiochim Biophys Acta
PubMed ID4063361
'We have investigated the initial kinetics of Ca2+-induced aggregation and fusion of phosphatidylserine large unilamellar vesicles at 3, 5 and 10 mM Ca2+ and 15, 25 and 35 degrees C, utilizing the Tb/dipicolinate (Tb/DPA) assay for mixing of aqueous vesicle contents and a resonance energy transfer (RET) assay for mixing ... More
Terbium as a luminescent probe of metal-binding sites in protein kinase C.
AuthorsWalters JD, Johnson JD
JournalJ Biol Chem
PubMed ID2106517
'In the present report, we demonstrate that Tb3+ binds to protein kinase C and serves as a luminescent reporter of certain cationic metal-binding sites. Tb3+ titration of 50 nM protein kinase C results in a 20-fold enhancement of Tb3+ luminescence which is half-maximal at 12 microM Tb3+. A Kd of ... More
Time-resolved fluorimetric detection of terbium-labelled deoxyribonucleic acid separated by gel electrophoresis.
AuthorsSaavedra SS, Picozza EG
JournalAnalyst
PubMed ID2802165
'Deoxyribonucleic acid (DNA) was reacted with a strong chelating agent and labelled with terbium, yielding a highly fluorescent conjugate with a lifetime of 1.5 ms. When a pulsed source and gated detection electronics were employed, the long-lived decay allowed effective discrimination against background fluorescence and scattered excitation. Detection limits should ... More
Kinetic measurements of fusion of phosphatidylserine-containing vesicles by electron microscopy and fluorometry.
AuthorsHui SW, Nir S, Stewart TP, Boni LT, Huang SK
JournalBiochim Biophys Acta
PubMed ID3132972
'Large unilamellar vesicles (REV) containing phosphatidylserine and phosphatidylethanolamine at a ratio of 1:3 were induced to fuse by adding calcium (4 mM). The kinetics of fusion was monitored by fluorometry using terbium or dipicolinic acid-containing vesicles. The morphology and the states of vesicle aggregation and fusion were examined at approx. ... More
Intensely luminescent immunoreactive conjugates of proteins and dipicolinate-based polymeric Tb (III) chelates.
AuthorsLamture JB, Wensel TG
JournalBioconjug Chem
PubMed ID7711110
'Partial alkylation of polylysine with 4-(iodoacetamido)-2,6-dimethylpyridine dicarboxylate (IADP), followed by exhaustive reaction with succinic anhydride, yielded polymers (PLDS, polymer of lysine, dipicolinate, and succinate) containing large numbers (50-100) of 4-substituted dipicolinic acid moieties per molecule, with the remaining lysyl side chains succinylated. Competition experiments showed that PLDS binds Tb(III) ions ... More
Different conformation changes induced by calcium and terbium of the porcine intestinal calcium-binding protein.
AuthorsChiba K, Mohri T
JournalBiochemistry
PubMed ID3567142
'The fluorescence of 1-anilino-8-naphthalenesulfonate (ANS) is progressively enhanced with increasing concentration of it, showing a proportionate blue shift of the emission maximum, by the interaction with the porcine intestinal Ca2+-binding protein (CaBP) in the absence of Ca2+. The apo-CaBP has a single binding site for ANS as determined by the ... More
The renaissance of fluorescence resonance energy transfer.
AuthorsSelvin PR
JournalNat Struct Biol
PubMed ID10966639
'Recent advances in fluorescence resonance energy transfer have led to qualitative and quantitative improvements in the technique, including increased spatial resolution, distance range, and sensitivity. These advances, due largely to new fluorescent dyes, but also to new optical methods and instrumentation, have opened up new biological applications.' ... More
Effect of physical constraints on the mechanisms of membrane fusion: bolaform lipid vesicles as model systems.
AuthorsRelini A, Cassinadri D, Fan Q, Gulik A, Mirghani Z, De Rosa M, Gliozzi A
JournalBiophys J
PubMed ID8889155
'Bolaform lipid vesicles were used to study the effect of physical constraints on membrane fusion. In these vesicles the membrane is organized in a single monolayer, because of the presence of covalent bonds in its middle plane. Therefore, the formation of fusion intermediates is subject to higher energy barriers and ... More
Binding of terbium to apoferritin: a fluorescence study.
AuthorsStefanini S, Chiancone E, Antonini E, Finazzi-Agro A
JournalArch Biochem Biophys
PubMed ID6847196
'Luminescence measurements show that apoferritin binds three Tb(III) atoms per subunit in accordance with crystallographic evidence. Fe(II) competes with Tb(III) for at least some of the binding sites. This competition may be the molecular basis for the inhibition of iron incorporation into apoferritin brought about by Tb(III). Ca(II), which is ... More
Terbium identifies double-stranded RNA on gels by quenching the fluorescence of intercalated ethidium bromide.
AuthorsAl-Hakeem M, Sommer SS
JournalAnal Biochem
PubMed ID3661991
'We report that the lanthanide cation terbium quenches the fluorescence of ethidium bromide bound to double-stranded RNA by 40-fold, whereas the quenching of double-stranded and single-stranded DNA is under 2.5-fold and the quenching of single-stranded RNA is under 5-fold. This observation was used to develop a convenient method of detecting ... More
A novel peptide designed for sensitization of terbium (III) luminescence.
AuthorsClark ID, Hill I, Sikorska-Walker M, MacManus JP, Szabo AG
JournalFEBS Lett
PubMed ID8224178
'Several synthetic peptides, modelled from a Ca(2+)-binding loop of the EF-hand family of proteins, were prepared containing cysteine residues. The peptide, GDKNADGFICFEEL, was labelled covalently at the cysteine residue (loop position 9) with iodoacetamidosalicylic acid. This novel conjugate is a metal-binding loop containing a salicylic acid side chain that could ... More
Ultrasensitive thyrotropin immunoassay based on enzymatically amplified time-resolved fluorescence with a terbium chelate.
AuthorsPapanastasiou-Diamandi A, Christopoulos TK, Diamandis EP
JournalClin Chem
PubMed ID1568319
'We describe an ultrasensitive, enzymatically amplified time-resolved fluorescence immunoassay of thyrotropin (thyroid-stimulating hormone) in serum with use of a terbium chelate as the detectable moiety. In this assay, thyrotropin is first simultaneously reacted with a solid-phase (microtiter well) monoclonal antibody and a soluble biotinylated monoclonal detection antibody. After washing, a ... More
A fusogenic protein from rat brain microsomal membranes: partial purification and reconstitution into liposomes.
AuthorsRakowska M, Zborowski J, Corazzi L
JournalJ Membr Biol
PubMed ID7707352
'The procedures for purification and reconstitution of rat brain microsomal membrane protein that causes fusion of liposomes at acidic pH are described. A 1,860-fold purification was achieved, starting from the detergent-solubilized microsomal membranes. The fusion process was assayed spectrofluorimetrically by monitoring the formation of terbium-dipicolinic acid complex (Wilschut, J. et ... More
Comparison of two liposome fusion assays monitoring the intermixing of aqueous contents and of membrane components.
AuthorsRosenberg J, Düzgünes N, Kayalar C
JournalBiochim Biophys Acta
PubMed ID6626546
'Divalent cation-induced fusion of large unilamellar vesicles (approx. 0.1 micron diameter) made of phosphatidylserine (PS) or phosphatidylglycerol (PG) has been studied. Intermixing of aqueous contents during fusion was followed by the Tb/dipicolinic acid fluorescence assay, and intermixing of membrane components by resonance energy transfer between fluorescent lipid probes. Both assays ... 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
Influence of inorganic cations and histone proteins on the terbium(III)-nucleic acid interaction.
AuthorsGross DS, Rice SW, Simpkins H
JournalBiochim Biophys Acta
PubMed ID7317431
'We have studied the interaction of the fluorescent lanthanide, terbium(III) (Tb3+), with polynucleotides and linear and superhelical DNA, through employment of mono- and multivalent cations as competitive inhibitors. Increasingly effective competitive inhibiton of the Tb3+-nucleic acid interaction was achieved, for the most part, in the cation order monovalent less than ... More
Self-association of Ca(2+)-binding peptides induced by lanthanide ions: a fluorescence study.
AuthorsClark ID, Brown CM, Sikorska-Walker M, MacManus JP, Szabo AG
JournalAnal Biochem
PubMed ID8238905
'In this study a Ca(2+)-binding 14mer peptide was synthesized with the sequence GDKNADGCIEFEEL, allowing covalent attachment of sulfhydryl-reactive fluorescent molecules at position 7 of the 12-residue, metal-binding loop (underlined). This provided the opportunity to select donor molecules with suitable spectral characteristics for sensitized excitation of chelated terbium (Tb3+) or europium ... More
Studies on the mechanism of membrane fusion: role of phosphate in promoting calcium ion induced fusion of phospholipid vesicles.
AuthorsFraley R, Wilschut J, Düzgünes N, Smith C, Papahadjopoulos D
JournalBiochemistry
PubMed ID7470446
'The role of phosphate in enhancing the calcium-induced fusion of phosphatidylserine (PS) vesicles has been examined by using the new fluorescent (terbium/dipicolinic acid) assay described by Wilschut et al. (1980) [Wilschut, J., Düzgünes, N., Fraley, R., & Papahajopoulos, D. (1980) Biochemistry (preceding paper in this issue)]. In the presence of ... More
Biochemical investigations and mapping of the calcium-binding sites of heparinase I from Flavobacterium heparinum.
AuthorsShriver Z, Liu D, Hu Y, Sasisekharan R
JournalJ Biol Chem
PubMed ID9933601
'The heparinases from Flavobacterium heparinum are lyases that specifically cleave heparin-like glycosaminoglycans. Previously, amino acids located in the active site of heparinase I have been identified and mapped. In an effort to further understand the mechanism by which heparinase I cleaves its polymer substrate, we sought to understand the role ... 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
A high-throughput screen for identifying transmembrane pore-forming peptides.
AuthorsRausch JM, Wimley WC
JournalAnal Biochem
PubMed ID11399041
'We have developed a visual microwell plate assay for rapid, high-throughput screening for membrane-disrupting molecules such as de novo designed pore formers, antibiotic peptides, bacterial toxins, and lipases. The detectability is based on the strong fluorescence emission of the lanthanide metal terbium(III) (Tb(3+)) when it interacts with the aromatic chelator ... More
Multiple end labeling of oligonucleotides with terbium chelate-substituted psoralen for time-resolved fluorescence detection.
AuthorsOser A, Collasius M, Valet G
JournalAnal Biochem
PubMed ID2085175
'A new procedure for the photochemical functionalization and the subsequent nonradioactive labeling of synthetic oligonucleotides with psoralen derivatives was developed where a double-stranded poly(A-T) tail is attached to the 5''- or 3''-end of the oligonucleotide to be labeled. The double-stranded poly(A-T) tail is covalently crosslinked by psoralen molecules which carry ... More
Lectins facilitate calcium-induced fusion of phospholipid vesicles containing glycosphingolipids.
AuthorsDüzgünes N, Hoekstra D, Hong K, Papahadjopoulos D
JournalFEBS Lett
PubMed ID6745438
'Ca2+-induced fusion of phospholipid vesicles containing globoside (GL-4) or disialoganglioside (GDla) is several-fold slower than the fusion of the pure phospholipid vesicles. Lectins specific for these glycosphingolipids, soybean agglutinin and wheat germ agglutinin, respectively, enhance the rate of fusion when added to the vesicle suspension before the introduction of Ca2+. ... More
Promotion and inhibition of vesicle fusion by polylysine.
AuthorsGad AE, Bental M, Elyashiv G, Weinberg H, Nir S
JournalBiochemistry
PubMed ID4084519
'Polylysine induced rapid aggregation of large unilamellar vesicles composed of phosphatidylcholine-cardiolipin (1:1 molar ratio) but not their fusion. Application of the terbium-dipicolinic acid fusion assay showed that addition of polylysine at nanomolar concentrations enabled a significant lowering of the Ca2+ threshold concentration for vesicle fusion from 9 to 1 mM. ... More
Effects of phorbol ester and teleocidin on Ca2+-induced fusion of liposomes.
AuthorsNam K, Kimura S, Fujiki H, Imanishi Y
JournalBiochem Biophys Res Commun
PubMed ID2610691
'The effects of different types of lipid membrane defects on Ca2+-induced fusion of liposomes containing phosphatidylserine (PS) were investigated using fluorescent probes. Teleocidin enhanced the fusion of phospholipid vesicles in an assay system using terbium/dipicolinic acid during mixing of internal aqueous phases of vesicles upon fusion. 12-O-Tetradecanoylphorbol-13-acetate (TPA) suppressed the ... More
Reverse fluorescence staining of proteins in polyacrylamide gels using terbium chloride.
AuthorsCopeland RA
JournalAnal Biochem
PubMed ID7978250
Lanthanides as probes for time-resolved fluorometric immunoassays.
AuthorsHemmilä I
JournalScand J Clin Lab Invest
PubMed ID3060984
Terbium chelates for fluorescence immunoassay.
AuthorsBailey MP, Rocks BF, Riley C
JournalAnalyst
PubMed ID3898916
Fusion assays monitoring intermixing of aqueous contents.
AuthorsDüzgünes N, Wilschut J
JournalMethods Enzymol
PubMed ID8350759
Diffusion-enhanced fluorescence energy transfer.
AuthorsStryer L, Thomas DD, Meares CF
JournalAnnu Rev Biophys Bioeng
PubMed ID7049062
Terbium chelate for use as a label in fluorescent immunoassays.
AuthorsBailey MP, Rocks BF, Riley C
JournalAnalyst
PubMed ID6397078
Terbium chelate labels for fluorescence immunoassays.
AuthorsSiepak J
JournalAnalyst
PubMed ID2667397
Bovine serum albumin was labelled with a terbium complex by means of a reagent prepared from diethylenetriaminepentaacetic acid or diethylenetriaminepentaphosphonic acid and p-aminosalicylic acid. The ternary mixed ligand complexes showed strong fluorescence and were stable in very dilute solution (10(-10)M). The fluorescence of the conjugated products was compared with regard ... More
AuthorsGuo CY, Shankar RR, Abe S, Ye Z, Thomas RN, Kuo JE
JournalAnal Biochem
PubMed ID1481977
Synthesis of surface-functionalized, probe-containing latex nanospheres is described. Approximately 40,000 probe ions may be encapsulated in a nanosphere of 50 nm diameter. The probe may be a radionuclide or a lanthanide with long-lived fluorescence. Alternatively, a "cargo" of pharmaceutical interest may be used. The surface of each nanosphere contains thousands ... More
Effect of phosphorylation of calmodulin on calcium binding affinity as estimated by terbium fluorescence.
AuthorsAiuchi T, Hagiwara T, Omata K, Nakaya K, Nakamura Y
JournalBiochem Int
PubMed ID1863267
The effect of phosphorylation of calmodulin by casein kinase 2 on the calcium binding of the former was studied by measurement of terbium fluorescence. The binding of Tb3+ to calmodulin was followed by an increase in Tb3+ fluorescence at 545 nm. The terbium fluorescence of phosphorylated calmodulin increased at a ... More
Tb(III) as a fluorescent probe for the structure of bovine serum albumin.
AuthorsJin YJ, Li WL, Wang QR
JournalBiochem Biophys Res Commun
PubMed ID1904219
Tb(III) was used as a fluorescent probe in the study of the calcium-binding sites on Bovine Serum Albumin (BSA). The fluorescence of Tb(III) is enhanced markedly when bound to BSA and nonradiative energy transfer between two fluorescent tryptophan(Trp) residues and Tb(III) bound to calcium-binding sites on BSA occurred. Experimental results ... More
Fusion of phosphatidylcholine liposomes induced by polyethylene glycol.
AuthorsMishra RK, Rajeswari MR, Singhal GS
JournalBiochem Int
PubMed ID3178863
Fusion of small unilamellar vesicles of L-alpha-phosphatidylcholihne (PC) was carried out in the presence of polyethylene glycol (PEG, Mr 6000-7500). The fusion of liposomes was detected by (i) monitoring the efficiency of energy transfer from chlorophyll b (Chl b) to chlorophyll a (Chl a), (ii) formation of fluorescent complex Tb ... More
Ca2+-induced fusion of cardiolipin/phosphatidylcholine vesicles monitored by mixing of aqueous contents.
AuthorsWilschut J, Holsappel M, Jansen R
JournalBiochim Biophys Acta
PubMed ID7126579
The kinetics of Ca2+-induced fusion of large (0.1 micrometer) unilamellar cardiolipin/phosphatidylcholine (1:1) vesicles have been investigated by continuous monitoring of the mixing of the aqueous vesicle contents. In parallel, release of vesicle contents to the external medium has been followed. Initial fusion of the vesicles is non-leaky, release of vesicle ... More
Fusion of negatively charged phospholipid vesicles by alpha-latrotoxin.
AuthorsLishko VK, Terletskaya YaT Trikash IO
JournalFEBS Lett
PubMed ID2365074
alpha-Latrotoxin-induced fusion of liposomes has been described using large unilamellar vesicles composed of phosphatidylcholine/phosphatidylethanolamine/cardiolipin at a molar ratio of 2:3:5. Vesicle fusion was monitored by terbium/dipicolinic acid assay as well as by fluorescence energy transfer measurement. The enhancement of the fusogenic effect of LTX by low concentrations (0.1-3 mM) of ... More
Detection of calcium binding proteins on polyacrylamide gels using time-resolved lanthanide luminescence photography.
AuthorsHill IE, Hogue CW, Clark ID, MacManus JP, Szabo AG
JournalAnal Biochem
PubMed ID7513974
Methods were developed for using the luminescent lanthanides Tb3+ and Eu3+ for the specific staining of calcium-binding proteins, as well as the nonspecific staining of proteins, on polyacrylamide gels. These methods involve equilibration of the gel after electrophoresis in solutions containing the appropriate lanthanide and a weak competitive chelating agent, ... More
Efflux of dipicolinic acid from human erythrocytes, sealed membrane fragments, and band 3-liposome complexes: a fluorescence probe for the erythrocyte anion transporter.
AuthorsNewton AC, Huestis WH
JournalAnal Biochem
PubMed ID3740418
The greatly enhanced fluorescence of Tb3+ when complexed with dipicolinic acid affords a simple and highly sensitive method for monitoring continuous anion flux through the erythrocyte anion transporter, band 3. Dipicolinic acid (pyridine-2,6-dicarboxylic acid) is entrapped in human erythrocytes and other band 3-membrane preparations. Efflux of dipicolinic acid from preequilibrated ... More
Detection of bacterial spores with lanthanide-macrocycle binary complexes.
The detection of bacterial spores via dipicolinate-triggered lanthanide luminescence has been improved in terms of detection limit, stability, and susceptibility to interferents by use of lanthanide-macrocycle binary complexes. Specifically, we compared the effectiveness of Sm, Eu, Tb, and Dy complexes with the macrocycle 1,4,7,10-tetraazacyclododecane-1,7-diacetate (DO2A) to the corresponding lanthanide aquo ... More
Airborne bacterial spore counts by terbium-enhanced luminescence detection: pitfalls and real values.
AuthorsLi Q, Dasgupta PK, Temkins HK,
JournalEnviron Sci Technol
PubMed ID18497126
Bacterial spore determination by terbium(III)-dipicolinate luminescence has been reported by several investigators. We collected spore samples with a cyclone and extracted dipicolinic acid (DPA) in-line with hot aqueous dodecylamine, added Tb(III) in a continuous-flow system and detected the Tb(III)-DPA with a gated liquid core waveguide fluorescence detector with a flashlamp ... More
Dipicolinic acid (DPA) assay revisited and appraised for spore detection.
AuthorsHindle AA, Hall EA,
JournalAnalyst
PubMed ID10746319
Delayed gate fluorescence detection of dipicolinic acid (DPA), a universal and specific component of bacterial spores, has been appraised for use in a rapid analytical method for the detection of low concentrations of bacterial spores. DPA was assayed by fluorimetric detection of its chelates with lanthanide metals. The influence of ... More
Effects of linker sequences on vesicle fusion mediated by lipid-anchored DNA oligonucleotides.
AuthorsChan YH, van Lengerich B, Boxer SG,
JournalProc Natl Acad Sci U S A
PubMed ID19164559
Synthetic lipid-oligonucleotide conjugates inserted into lipid vesicles mediate fusion when one population of vesicles displays the 5'-coupled conjugate and the other the 3'-coupled conjugate, so that anti-parallel hybridization allows the membrane surfaces to come into close proximity. Improved assays show that lipid mixing proceeds more quickly and to a much ... More
Time-resolved pulsed fluorescence immunometric assays of carcinoembryonic antigen.
AuthorsDakubu S, Hale R, Lu A, Quick J, Solas D, Weinberg J
JournalClin Chem
PubMed ID3052929
A time-resolved pulsed fluorescence immunometric assay (TR-PFIA) for carcinoembryonic antigen is described in which either Eu(III) or Tb(III) chelate is used as label. Described in detail is the assay involving the well-documented format of microtiter matrix and Eu(III) fluorescence enhanced with a beta-diketone and quantified in a commercial time-resolving fluorometer. ... More
Double-label time-resolved immunofluorometry of lutropin and follitropin in serum.
AuthorsHemmilä I, Holttinen S, Pettersson K, Lövgren T
JournalClin Chem
PubMed ID3121216
We describe a procedure for the simultaneous immunofluorometric assay of lutropin and follitropin in human serum, based on the use of monoclonal antibodies and of the fluorescent lanthanides Eu3+ and Tb3+. The alpha-chain-specific antibody was used as a common capture antibody on the surfaces of microtitration strips. The anti-beta-follitropin antibody ... More
Binding of terbium and of an elastase inhibitor to bovine pancreatic subunit III, an inactive protease E.
AuthorsChapus C, Kerfelec B, Dimicoli JL
JournalJ Biol Chem
PubMed ID2303477
Using the Tb3+ luminescence technique, we showed that bovine subunit III, a defective pancreatic serine endopeptidase-like protease, possessed a single metal ion binding site able to bind Tb3+ with a high affinity comparable to that of porcine elastase. The topology of the metal ion binding site in subunit III is ... More
Fluorescence of phosphotyrosine--terbium(III) complexes.
Phosphotyrosine, a biologically important protein residue, was investigated for the ability to enhance terbium (Tb3+) fluorescence. Spectroscopic analysis of the Tb3+: phosphotyrosine interaction indicated the development of a new excitation peak at 275 nm and strong Tb+ fluorescence enhancement at 488 and 540 nm that was linear over a range ... More
The binding of substrates and inhibitors to the metal center of myoinositol monophosphatase.
AuthorsKwok F, Churchich JE
JournalFEBS Lett
PubMed ID8013651
The synthetic substrate anthraniloyl-beta-glycerol-P binds to myoinositol monophosphatase with a Kd = 5 microM at pH 7.5. The anthraniloyl chromophore, excited at 330 nm, sensitizes the long lived luminescence of bound Tb(III) at 490, 545, 585 and 620 nm. Assuming a mechanism of radiationless energy transfer, the actual distance of ... More
Thiol-reactive luminescent chelates of terbium and europium.
AuthorsChen J, Selvin PR
JournalBioconjug Chem
PubMed ID10077482
Thiol-reactive lanthanide complexes have been synthesized that are luminescent when bound to terbium and/or europium. The complexes consist of a diethylenetriaminepentaacetate (DTPA) chelate covalently joined through one amide bond to a chromophore, carbostyril 124, and via a second amide bond to a maleimide, bromoacetamide, or pyridyldithio moiety. Site-specific attachment and ... 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
Simultaneous measurement of natural killer cell cytotoxicity against each of three different target cell lines.
AuthorsBlomberg K
JournalJ Immunol Methods
PubMed ID8308301
A time-resolved fluorometric assay for the simultaneous measurement of natural killer cell activity against three different lanthanide diethylenetriaminopentaacetate (LaDTPA) labelled target cell lines is described. The target cell line K-562 was labelled with SmDTPA, the cell line Molt with TbDTPA and the cell line Raji with EuDTPA. After co-incubation of ... More
Elucidation of the metal-binding properties of the Klenow fragment of Escherichia coli polymerase I and bacteriophage T4 DNA polymerase by lanthanide(III) luminescence spectroscopy.
BACKGROUND: The exonuclease active site of the Klenow fragment (KF) of Escherichia coli DNA polymerase I has a double binding site for the two essential divalent metal ions in the presence of the nucleotide monophosphate dTMP. RESULTS: The luminescence spectroscopy observed upon binding of Eu3+ to the exonuclease active site ... More
Luminescence energy transfer using a terbium chelate: improvements on fluorescence energy transfer.
AuthorsSelvin PR, Hearst JE
JournalProc Natl Acad Sci U S A
PubMed ID7937831
We extend the technique of fluorescence resonance energy transfer (FRET) by introducing a luminescent terbium chelate as a donor and an organic dye, tetramethylrhodamine, as an acceptor. The results are consistent with a Förster theory of energy transfer, provided the appropriate parameters are used. The use of lanthanide donors, in ... More
Fluorometric and time-resolved immunofluorometric assays for protein-tyrosine phosphatase activity.
AuthorsGalvan B, Christopoulos TK
JournalClin Biochem
PubMed ID8601320
OBJECTIVE: To develop sensitive nonisotopic assays for protein-tyrosine phosphatase (PTP) activity. METHODS: The fluorometric assay is based on the fact that phosphotyrosine but not tyrosine forms highly fluorescent complexes with Tb3+. Thus, PTP activity can be followed by measuring the decrease of fluorescence due to hydrolysis of phosphotyrosine. The time-resolved ... More
Amine-reactive forms of a luminescent diethylenetriaminepentaacetic acid chelate of terbium and europium: attachment to DNA and energy transfer measurements.
AuthorsLi M, Selvin PR
JournalBioconjug Chem
PubMed ID9095352
An isothiocyanate form of a lanthanide chelate which is highly luminescent when bound to terbium or europium has been synthesized. The chelate consists of diethylenetriaminepentaacetic acid (DTPA) covalently joined to a chromophore, 7-amino-4-methyl-2(1H)-quinolinone (cs124), and to L-p-aminophenylalanine, in which the aromatic amine was further converted to an isothiocyanate group. Ethylenediamine ... More
Effects of polycations on Ca2+ binding to the Ca(2+)-ATPase.
AuthorsHughes G, Khan YM, East JM, Lee AG
JournalBiochem J
PubMed ID7772032
Spermine and polyarginine have been shown to increase the rate of dissociation of Ca2+ from the Ca(2+)-ATPase of skeletal-muscle sarcoplasmic reticulum. They also decrease the affinity of the ATPase for Mg2+ as detected by changes in the fluorescence intensity of the ATPase labelled with 4-(bromomethyl)-6,7-dimethoxycoumarin (DMC). Polyarginine itself also decreases ... More
Ca2+-induced fusion of large unilamellar phosphatidylserine/cholesterol vesicles.
AuthorsBental M, Wilschut J, Scholma J, Nir S
JournalBiochim Biophys Acta
PubMed ID3828344
The effect of cholesterol on the Ca2+-induced aggregation and fusion of large unilamellar phosphatidylserine (PS) vesicles has been investigated. Mixing of aqueous vesicle contents was followed continuously with the Tb/dipicolinate assay, while the dissociation of pre-encapsulated Tb/dipicolinate complex was taken as a measure of the release of vesicle contents. Vesicles ... More
Simultaneous quadruple-label fluorometric immunoassay of thyroid-stimulating hormone, 17 alpha-hydroxyprogesterone, immunoreactive trypsin, and creatine kinase MM isoenzyme in dried blood spots.
AuthorsXu YY, Pettersson K, Blomberg K, Hemmilä I, Mikola H, Lövgren T
JournalClin Chem
PubMed ID1394988
We describe a quadruple-label fluorometric immunoassay for simultaneously measuring four analytes: thyroid-stimulating hormone (TSH), 17 alpha-hydroxyprogesterone (17 alpha-OHP), immunoreactive trypsin (IRT), and creatine kinase MM (CK-MM). The assay is based on immunoreagents labeled with four different lanthanide ions (Eu3+, Tb3+, Sm3+, and Dy3+), on dissociative fluorescence enhancement applying the principle ... More
The interaction of platinum and anthrapyrazole antitumor drugs with mouse thymocytes studied by terbium fluorescence.
AuthorsSimpkins H, Figliomeni M, Rosen M
JournalBiochim Biophys Acta
PubMed ID2846072
The fluorescent lanthanide, terbium has been employed to study the effect of a series of platinum and anthracycline drugs and an anthrapyrazole (oxanthrazole) on terbium binding to mouse thymocytes. It was observed that terbium fluorescence intensity was markedly decreased by two platinum drugs (cis-dichlorodiammine platinum(II) (cis-DDP) and cis-dichloro-trans-dihydroxybis(isopropylammine) platinum(IV) (CHIP)) ... More
pH-dependent structural transition in rabbit skeletal troponin C.
AuthorsWang CL, Zhan Q, Tao T, Gergely J
JournalJ Biol Chem
PubMed ID3597429
Although the crystal structure of troponin C is known (Herzberg, O., and James, M. N. G. (1985) Nature 313, 653-659; Sundaralingam, M., Bergstrom, R., Strasburg, G., Rao, S. T., Roychowdhury, P., Greaser, M., and Wang, B. C. (1985) Science 227, 945-948), its structure in solution, particularly under physiological conditions, has ... More
Ca2+-induced fusion of phospholipid vesicles monitored by mixing of aqueous contents.
AuthorsWilschut J, Papahadjopoulos D
JournalNature
PubMed ID551288
Ca2+ has a central role in various cellular phenomena involving membrane fusion. However, little is known about the mechanisms involved. Model membrane systems such as phospholipid vesicles have been used extensively to study the mechanism of membrane fusion at the molecular level. For example, phosphatidylserine (PS) vesicles have been shown ... More
No entry for TAT(44-57) into liposomes and intact MDCK cells: novel approach to study membrane permeation of cell-penetrating peptides.
AuthorsKrämer SD, Wunderli-Allenspach H
JournalBiochim Biophys Acta
PubMed ID12543377
Cell penetrating peptides (CPPs) have been postulated to carry macromolecules across cell plasma membranes without the need of receptors, transporters, endocytosis or any energy-consuming mechanism. We developed an assay to study lipid bilayer permeation of CPPs. HIV-1 TAT peptides were conjugated to N-(4-carboxy-3-hydroxyphenyl)maleimide (SAM) and incubated with Tb(3+)-containing liposomes. Upon ... More
Terbium simulates the action of calcium on electrophysiological activity in the isolated fish retina.
AuthorsDakin SR, Ruddock KH
JournalNeurosci Lett
PubMed ID2385367
It has been suggested that terbium (Tb) could be substituted for calcium (Ca) in biological tissue and, because of its useful spectroscopic properties, provide an assessment of calcium distribution in the tissue. In order to assess their physiological effects, we have examined the action of free terbium ions on the ... More
Distances between the functional sites of the (Ca2+ + Mg2+)-ATPase of sarcoplasmic reticulum.
AuthorsScott TL
JournalJ Biol Chem
PubMed ID2932447
Luminescence energy transfer measurements have been used to determine the distances between the two high affinity Ca2+ binding-transport sites of the (Ca2+ + Mg2+)-ATPase of skeletal muscle sarcoplasmic reticulum. The lanthanide Tb3+ situated at one high affinity Ca2+ site was used as the transfer donor, and acceptors at the other ... More
Activation of calpain I and calpain II: a comparative study using terbium as a fluorescent probe for calcium-binding sites.
AuthorsZimmerman UJ, Schlaepfer WW
JournalArch Biochem Biophys
PubMed ID2847653
The present study demonstrates the activation of calpain I and calpain II by micromolar levels of terbium and has utilized the enhancement in the fluorescence of protein-bound terbium to study and compare the calcium binding sites of the two enzymes. Calpain I and calpain II were isolated from bovine erythrocytes ... More
Diffusion-enhanced energy transfer shows accessibility of ribonucleic acid polymerase inhibitor binding sites.
AuthorsMeares CF, Rice LS
JournalBiochemistry
PubMed ID7011368
Rifamycin and Cibacron Blue F3GA are powerful inhibitors of Escherichia coli deoxyribonucleic acid (DNA) dependent ribonucleic acid (RNA) polymerase. In addition, both inhibitors strongly absorb visible light, making them suitable for use as acceptors in energy-transfer experiments. Transfer of energy to these acceptors from freely diffusing energy donors with long ... More
Engineering a terbium-binding site into an integral membrane protein for luminescence energy transfer.
AuthorsVázquez-Ibar JL, Weinglass AB, Kaback HR
JournalProc Natl Acad Sci U S A
PubMed ID11891311
Luminescence resonance energy transfer with a lanthanide like Tb(3+) as donor is a useful technique for estimating intra- and intermolecular distances in macromolecules. However, the technique usually requires the use of a bulky chelator with a flexible linker attached to a Cys residue to bind Tb(3+) and, for intramolecular studies, ... More
Binding of fluorescent lanthanides to rat liver mitochondrial membranes and calcium ion-binding proteins.
AuthorsMikkelsen RB, Wallach DF
JournalBiochim Biophys Acta
PubMed ID6061
(1) Tb3+ binding to mitochondrial membranes can be monitored by enhanced ion fluorescence at 545 nm with excitation at 285 nm. At low protein concentrations (less than 30 mug/ml) no inner filter effects are observed. (2) This binding is localized at the external surface of the inner membrane and is ... More
Influence of alpha-tocopherol incorporation on Ca(2+)-induced fusion of phosphatidylserine vesicles.
The effect of alpha-tocopherol on the Ca(2+)-induced fusion of large unilamellar phosphatidylserine vesicles has been investigated. Mixing of aqueous vesicle contents was followed continually with the terbium-dipicolinic acid (Tb-DPA) assay, while the dissociation of preencapsulated Tb-DPA complex was taken as a measure of the release of vesicle contents. Vesicles consisting ... More
Calmodulin binds to caldesmon in an antiparallel manner.
AuthorsWang E, Zhuang S, Kordowska J, Grabarek Z, Wang CL
JournalBiochemistry
PubMed ID9398229
Two of the five tryptophan residues (W659 and W692) in chicken gizzard smooth muscle caldesmon (CaD) are located within the calmodulin (CaM) binding sites in the C-terminal region of the molecule. When these Trp residues are replaced with Gly in either recombinant fragments or synthetic peptides of CaD, the affinity ... More
Fusion of phospholipid vesicles induced by muscle glyceraldehyde-3-phosphate dehydrogenase in the absence of calcium.
AuthorsMorero RD, Viñals AL, Bloj B, Farías RN
JournalBiochemistry
PubMed ID4016090
Ca2+-induced fusion of phospholipid vesicles (phosphatidylcholine/phosphatidic acid, 9:1 mol/mol) prepared by ethanolic injection was followed by five different procedures: resonance energy transfer, light scattering, electron microscopy, intermixing of aqueous content, and gel filtration through Sepharose 4-B. The five methods gave concordant results, showing that vesicles containing only 10% phosphatidic acid ... More
Terbium(III) luminescence study of the spatial relationship of tryptophan residues to the two metal ion binding sites of Escherichia coli glutamine synthetase.
The luminescence of Tb(III) was used to explore the topography of the metal ion sites of Escherichia coli glutamine synthetase and the relationship between these sites and tryptophan residues of the enzyme. By irradiation of tryptophan residues at 295 nm and measurement of the resulting Tb(III) luminescence at 544 nm, ... More
Time-Resolved Fluorescence Energy Transfer DNA Helicase Assays for High Throughput Screening.
AuthorsEarnshaw DL, Moore KJ, Greenwood CJ, Djaballah H, Jurewicz AJ, Murray KJ, Pope AJ
JournalJ Biomol Screen
PubMed ID10838444
DNA helicases are responsible for the unwinding of double-stranded DNA, facilitated by the binding and hydrolysis of 5'-nucleoside triphosphates. These enzymes represent an important class of targets for the development of novel anti-infective agents particularly because opportunity exists for synergy with existing therapies targeted at other enzymes involved in DNA ... More
Resonance energy transfer study on the proximity relationship between the GTP binding site and the rifampicin binding site of Escherichia coli RNA polymerase.
AuthorsKumar KP, Chatterji D
JournalBiochemistry
PubMed ID2405899
Terbium (III) upon complexation with guanosine 5'-triphosphate showed remarkable enhancement of fluorescence emission at 488 and 545 nm when excited at 295 nm. Analysis of the binding data yielded a value for the mean Kd between Tb(III) and GTP of 0.2 microM, with three binding sites for Tb(III) on GTP. ... More
Modulation of membrane fusion by membrane fluidity: temperature dependence of divalent cation induced fusion of phosphatidylserine vesicles.
AuthorsWilschut J, Düzgünes N, Hoekstra D, Papahadjopoulos D
JournalBiochemistry
PubMed ID3994974
We have investigated the temperature dependence of the fusion of phospholipid vesicles composed of pure bovine brain phosphatidylserine (PS) induced by Ca2+ or Mg2+. Aggregation of the vesicles was monitored by 90 degrees light-scattering measurements, fusion by the terbium/dipicolinic acid assay for mixing of internal aqueous volumes, and release of ... More
Membrane fusion: lipid vesicles as a model system.
AuthorsWilschut J, Hoekstra D
JournalChem Phys Lipids
PubMed ID3742671
In many cellular functions the process of membrane fusion is of vital importance. It occurs in a highly specific and strictly controlled fashion. Proteins are likely to play a key role in the induction and modulation of membrane fusion reactions. Aimed at providing insight into the molecular mechanisms of membrane ... More
In situ molecular association of dystrophin with actin revealed by sensitized emission immuno-resonance energy transfer.
AuthorsRoot DD
JournalProc Natl Acad Sci U S A
PubMed ID9159133
A novel method was developed to detect molecular associations of dystrophin with actin in cryostat muscle tissue sections by combining resonance energy transfer technology with immunohistochemical techniques. This method takes advantage of the long phosphorescent lifetime of terbium chelates, a property that enables the accurate determination of energy transfer in ... More
Change in conformation of plasma membrane phospholipid scramblase induced by occupancy of its Ca2+ binding site.
AuthorsStout JG, Zhou Q, Wiedmer T, Sims PJ
JournalBiochemistry
PubMed ID9778361
Phospholipid (PL) scramblase is a 35.1 kDa plasma membrane protein that mediates the accelerated transbilayer migration of plasma membrane PL in activated, injured, or apoptotic cells exposed to elevated intracellular Ca2+. We recently identified a conserved segment in the PL scramblase polypeptide (residues Asp273 to Asp284) that is essential for ... More