Shape and lipid-binding site of the nonspecific lipid-transfer protein (sterol carrier protein 2): a steady-state and time-resolved fluorescence study.
'The nonspecific lipid-transfer protein (nsL-TP) from bovine liver was studied with time-resolved and steady-state fluorescence techniques. From the decay of the intrinsic tryptophanyl fluorescence, it was estimated that the rotational correlation time of nsL-TP is 15 ns. This parameter increased only slightly upon addition of an excess of negatively charged ... More
Molecular and macromolecular specificity of human plasma phospholipid transfer protein.
AuthorsRao R, Albers JJ, Wolfbauer G, Pownall HJ
JournalBiochemistry
PubMed ID9132017
'Phospholipid transfer protein (PLTP), also known as lipid transfer protein 2 (LTP-2), mediates a transfer of phospholipids between high-density lipoproteins (HDL). The molecular and macromolecular specificities of recombinant human PLTP were studied using a fluorometric assay based on the excimer fluorescence of pyrenyl lipids. To determine lipoprotein specificity of PLTP, ... More
Evidence for phospholipid microdomain formation in liquid crystalline liposomes reconstituted with Escherichia coli lactose permease.
AuthorsLehtonen JY, Kinnunen PK
JournalBiophys J
PubMed ID9138570
'The well-characterized integral membrane protein lactose (lac) permease from Escherichia coli was reconstituted together with trace amounts (molar fraction X = 0.005 of the total phospholipid) of different pyrene-labeled phospholipid analogs into 1-palmitoyl-2-oleoyl-sn-glycero-3-sn-glycero-3-phospho-rac'-glycerol (POPG) liposomes. Effects of lac permease on bilayer lipid dynamics were investigated by measuring the excimer-to-monomer fluorescence ... More
Hydrolysis of phospholipid monolayers by human spermatozoa. Inhibition by male contraceptive gossypol.
'Monomolecular films of phospholipid were used to study the interaction of intact human spermatozoa with model membranes. Exclusively with negatively charged phosphatidylglycerol monolayers rapid penetration of spermatozoa into the monolayer with subsequent hydrolysis of the lipid was triggered by the addition of 5 mM calcium into the medium. The results ... More
Binding of quinacrine to acidic phospholipids and pancreatic phospholipase A2. Effects on the catalytic activity of the enzyme.
AuthorsMustonen P, Lehtonen JY, Kinnunen PK
JournalBiochemistry
PubMed ID9724516
'Binding of quinacrine to phospholipids and porcine pancreatic phospholipase A2 (PLA2) was investigated using fluorescence resonance energy transfer, Langmuir films, assay for the enzymatic activity, and molecular modeling. No significant binding of this drug to the zwitterionic phosphatidylcholine was observed whereas a high affinity for acidic phospholipids was revealed by ... More
Binding of adriamycin to liposomes as a probe for membrane lateral organization.
AuthorsSöderlund T, Jutila A, Kinnunen PK
JournalBiophys J
PubMed ID9929491
'A stopped-flow spectrofluorometer equipped with a rapid scanning emission monochromator was utilized to monitor the binding of adriamycin to phospholipid liposomes. The latter process is evident as a decrease in fluorescence emission from a trace amount of a pyrene-labeled phospholipid analog (PPDPG, 1-palmitoyl-2-[(6-pyren-1-yl)]decanoyl-sn-glycero-3-phospho-rac-++ +glyce rol) used as a donor for ... More
'Recent studies suggest that phosphoinositide kinases may participate in intracellular trafficking or exocytotic events. Because both of these events ultimately require fusion of biological membranes, the susceptibility of membranes containing polyphosphoinositides (PPIs) to divalent cation-induced fusion was investigated. Results of these investigations indicated that artificial liposomes containing PPI or phosphatidic ... More
Fourier transform infrared study on the thermotropic behaviour of fully hydrated 1-palmitoyl-2-[10-(pyren-1-y) decanoyl]-sn-glycero-3-phosphatidylcholine.
AuthorsLotta TI, Virtanen JA, Kinnunen PK
JournalChem Phys Lipids
PubMed ID3338098
'Fourier transform infrared (FTIR) spectroscopy was used to study the thermotropic behaviour of fully hydrated 1-palmitoyl-2-[10-(pyren-1-yl)-decanoyl]-sn-glycero-3-phosphatidyl choline (PPDPC) in the temperature range of 3-30 degrees C. Several changes in the spectral features of PPDPC were observed. Major alterations analogous to the gel-to-liquid crystalline phase transition of saturated phosphatidylcholines were evident ... More
Estimation of the equilibrium lateral pressure in 1-palmitoyl-2-[6(pyren-1-yl)]hexanoyl-glycerophospholipid liposomes.
AuthorsThuren T, Virtanen JA, Kinnunen PK
JournalChem Phys Lipids
PubMed ID3815626
'Compression isotherms for 1-palmitoyl-2-[6(pyren-1-yl)] hexanoyl-sn-glycero-3-phosphocholine (PPHPC), -ethanolamine (PPHPE), -glycerol (PPHPG), -serine (PPHPS) and -phosphatidic acid monomethylester (PPHPM) were recorded at an argon/water interface. Thereafter, the ratios of pyrene excimer to monomer fluorescence emission intensities (Ie/Im) were determined for liposomes of these lipids and were found to be 20.15, 12.30, 11.80, ... More
Determination of the acyl chain specificity of the bovine liver phosphatidylcholine transfer protein. Application of pyrene-labeled phosphatidylcholine species.
AuthorsSomerharju PJ, van Loon D, Wirtz KW
JournalBiochemistry
PubMed ID3427069
'The phosphatidylcholine transfer protein from bovine liver has specific binding sites for the sn-1 and sn-2 acyl chains of the phosphatidylcholine molecule [Berkhout, T.A., Visser, A.J. W.G., & Wirtz, K.W.A. (1984) Biochemistry 23, 1505-1513]. In the present study, we have investigated the properties of these binding sites by determining both ... More
Activation of phospholipase D by phosphatidic acid. Enhanced vesicle binding, phosphatidic acid-Ca2+ interaction, or an allosteric effect?
AuthorsGeng D, Chura J, Roberts MF
JournalJ Biol Chem
PubMed ID9575167
'The activity of bacterial phospholipase D (PLD), a Ca2+-dependent enzyme, toward phosphatidylcholine bilayers was enhanced 7-fold by incorporation of 10 mol % phosphatidic acid (PA) in the vesicle bilayer. Addition of other negatively charged lipids such as phosphatidylinositol, phosphatidylmethanol, and oleic acid either inhibited or had no effect on enzyme ... More
Oxidation of unsaturated phospholipids in membrane bilayer mixtures is accompanied by membrane fluidity changes.
AuthorsBorst JW, Visser NV, Kouptsova O, Visser AJ
JournalBiochim Biophys Acta
PubMed ID10962288
'Steady-state and time-resolved fluorescence spectroscopy has been used to obtain information on oxidation processes and associated dynamical and structural changes in model membrane bilayers made from single unilamellar vesicles (SUV''s) of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) mixed with increasing amounts of 1-stearoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (SAPC). The highly unsaturated arachidonoyl chain containing four double bonds is ... More
Fluorometric assay for phospholipase A2 in serum.
AuthorsThuren T, Virtanen JA, Lalla M, Kinnunen PK
JournalClin Chem
PubMed ID3987000
In this fluorometric assay for phospholipase A2 (EC 3.1.1.4) in serum we use the fluorescent phospholipid analog 1-octacosanyl-2-(pyren-1-yl)hexanoyl-sn-glycero-3-phosphatid yl monomethyl ester as substrate. The optimized conditions are: 28 mumol of the substrate per liter of Tris buffer (20 mmol/L, pH 7.4). The hydrolytic reaction is allowed to proceed for 30 ... More
Pyrene-labeled lipids as tools in membrane biophysics and cell biology.
AuthorsSomerharju P
JournalChem Phys Lipids
PubMed ID12093535
Pyrene is one of the most frequently used lipid-linked fluorophores. Its most characteristic features are a long excited state lifetime and (local) concentration-dependent formation of excimers. Pyrene is also hydrophobic and thus does not significantly distort the conformation of the labeled lipid molecule. These characteristics make pyrene lipids well-suited for ... More
A sensitive and continuous fluorometric assay for phospholipase A2 using pyrene-labeled phospholipids in the presence of serum albumin.
AuthorsRadvanyi F, Jordan L, Russo-Marie F, Bon C
JournalAnal Biochem
PubMed ID2742139
Phospholipase A2 activity can be determined fluorometrically in the presence of serum albumin using phospholipids labeled at the sn-2-acyl position with 10-pyrenyldecanoic acid. In the water reaction medium 10-pyrene phospholipids form vesicles and the monomer fluorescence of the pyrene is negligible due to pyrene-pyrene interaction. Upon phospholipid hydrolysis 10-pyrenyldecanoic acids ... More
Hydrolysis of 1-palmitoyl-2-[6-(pyren-1-yl)]hexanoyl-sn-glycero- 3-phospholipids by phospholipase A2: effect of the polar head-group.
AuthorsThuren T, Virtanen JA, Verger R, Kinnunen PK
JournalBiochim Biophys Acta
PubMed ID3801511
The effect of the phospholipid polar head-group on the porcine pancreatic phospholipase A2 (phosphatidylcholine 2-acylhydrolase, EC 3.1.1.4) reaction was studied using 1-palmitoyl-2-[6-(pyren-1-yl)]hexanoyl-sn-glycero-3- phosphatidylcholine, -ethanolamine, -glycerol, -monomethylester and -serine as substrates. Except for the monomethylester analogue, which was maximally activated by 3.5 mM CaCl2, maximal enhancement of hydrolysis of the other ... More
Direct, ultrasensitive, and selective optical detection of protein toxins using multivalent interactions.
AuthorsSong X, Swanson BI
JournalAnal Chem
PubMed ID10366891
Three highly sensitive, selective, and reagent-free optical signal transduction methods for detection of polyvalent proteins have been developed by directly coupling distance-dependent fluorescence self-quenching and/or resonant-energy transfer to the protein-receptor binding events. The ganglioside GM1, as the recognition unit for cholera toxin (CT), was covalently labeled with fluorophores and then ... More
Binding of cytochrome c to liposomes as revealed by the quenching of fluorescence from pyrene-labeled phospholipids.
AuthorsMustonen P, Virtanen JA, Somerharju PJ, Kinnunen PK
JournalBiochemistry
PubMed ID3038173
Resonance energy transfer from pyrene-fatty acid containing phospholipid derivatives to the heme of cytochrome c (cyt c) was used to observe the binding of this protein to liposomal membranes. Liposomes were formed of egg yolk phosphatidic acid (PA) and either egg yolk phosphatidylcholine or dipalmitoylphosphatidylcholine with 1 mol % of ... More
On the reversal by deoxyribonucleic acid of the binding of adriamycin to cardiolipin-containing liposomes.
AuthorsMustonen P, Kinnunen PK
JournalJ Biol Chem
PubMed ID7678246
The binding of the cytotoxin adriamycin (doxorubicin) to phospholipids, DNA, and RNA was investigated using (i) fluorescence quenching by this drug of liposomes containing pyrene-labeled phospholipids and (ii) monomolecular cardiolipin films on an air/water interface. In accordance with previous studies, our fluorescence experiments revealed that the acidic phospholipids, phosphatidylglycerol, phosphatidylmethanol, ... More
Effects of unsaturation and curvature on the transverse distribution of intramolecular dynamics of dipyrenyl lipids.
AuthorsCheng KH, Somerharju P
JournalBiophys J
PubMed ID9172752
The roles of acyl chain unsaturation and curvature in the excimer formation efficiency (EFE) of site-specific conjugated pyrene molecules in lipid membranes have been investigated by steady-state and time-resolved fluorescence spectroscopy. Six 1-2-(pyrenyl-n-acyl)-phosphatidylcholine (dipy(n)PC) probes, with pyrenyl chains of varying methylene units n from 4 to 14 carbons, were incorporated ... More
Reversible, nonionic, and pH-dependent association of cytochrome c with cardiolipin-phosphatidylcholine liposomes.
AuthorsRytömaa M, Mustonen P, Kinnunen PK
JournalJ Biol Chem
PubMed ID1331048
Membrane association of cytochrome c (cyt c) was monitored by the efficiency of resonance energy transfer from a pyrene-fatty acid containing phospholipid derivative (1-palmitoyl-2[6-(pyren-1-yl)]hexanoyl-sn-glycero-3-phosphocholine (PPHPC)) to the heme of cyt c. Liposomes consisted of 85 mol% egg phosphatidylcholine (egg PC), 10 mol% cardiolipin, and 5 mol% PPHPC. Cardiolipin was necessary ... More
Transversal distribution of acyl-linked pyrene moieties in liquid-crystalline phosphatidylcholine bilayers. A fluorescence quenching study.
AuthorsSassaroli M, Ruonala M, Virtanen J, Vauhkonen M, Somerharju P
JournalBiochemistry
PubMed ID7612625
Quenching of the fluorescence of pyrene-labeled phospholipids by dibromolipids was used to determine the chain length dependence of the bilayer depths of the pyrenyl moieties. Six 1-palmitoyl-2-(pyrenyl-n-acyl)-phosphatidylcholines (PyrnPC) were examined, with end-labeled pyrenyl chains varying in length, n, from 4 to 14 carbons. These lipids were incorporated, at a concentration ... More
Effects of sphingosine on peripheral membrane interactions: comparison of adriamycin, cytochrome c, and phospholipase A2.
AuthorsMustonen P, Lehtonen J, Kõiv A, Kinnunen PK
JournalBiochemistry
PubMed ID8388718
As revealed by resonance energy transfer utilizing pyrene-labeled phosphatidylcholine donor, the mainly electrostatically controlled binding of adriamycin (Adr) and cytochrome c (cyt c) to mixed egg yolk phosphatidic acid/phosphatidylcholine (eggPA/eggPC, 15:85 molar ratio) liposomes was reversed upon the inclusion of increasing contents of sphingosine. At a [sphingosine]/[eggPA] molar ratio of ... More