Resonance energy transfer study of peptide-lipid complexes.

Resonance energy transfer involving tryptophan as a donor and anthrylvinyl-labeled phosphatidylcholine (AV-PC), 3-methoxybenzanthrone (MBA) and 8-anilino-1-naphthalene sulfonic acid (ANS) as acceptors has been examined to obtain information on the structure of peptide-lipid systems consisting of 18A or Ac-18A-NH(2) peptides and large unilamellar phosphatidylcholine vesicles. The lower and upper limits for the tryptophan distance from the bilayer midplane have been assessed in terms of the models of energy transfer in two-dimensional systems, taking into account orientational effects. Evidence for the existence of preferential orientations of Ac-18A-NH(2) with respect to the lipid-water interface has been obtained.

[Study of model protein-lipid systems by the energy transfer method]. / Issledovanie model'nykh belok-lipidnykh sistem metodom perenosa énergii.

Complexes of ribonuclease, lysozyme, cytochrome c and hemoglobin with model phospholipid membranes composed of phosphatidylcholine and diphosphatidylglycerol (4:3, mol:mol) were investigated by the method of non-radiative fluorescence energy transfer. Evidence for the penetration of proteins in to the lipid bilayer interior was obtained. The size of the protein fragment incorporated into the polar membrane region was estimated.

Resonance energy transfer study of hemoglobin complexes with model phospholipid membranes.

By examining the resonance energy transfer between fluorescent probes, embedded in the lipid bilayer (4-(dimethylaminostyryl)-1-methylpiridine, 4-(dimethylaminostyryl)-1-dodecylpiridine, N,N'-bishexamethylenrhodamine, rhodamine 6G) as donors, and the heme group of hemoglobin as acceptor, the structure of the protein complexes with the model membranes composed of phosphatidylcholine and cardiolipin was characterized. Quantitative interpretation of the experimental data was performed in terms of the model of energy transfer in two-dimensional systems, using a set of parameters including the distance of closest approach between donor and acceptor, the vertical separation of donor planes, the acceptor distance from the donor plane and the orientation factor. The limits for the heme distance from the lipid bilayer center and the depth of the protein penetration in the membrane interior were estimated. The results obtained suggest that the depth of hemoglobin insertion into liposomal membranes decreases upon increasing CL content in the lipid bilayer.

Structure of cytochrome c complexes with phospholipids as revealed by resonance energy transfer.

Resonance energy transfer between a series of lipid-bound fluorescent probes as donors and the heme group of cytochrome c as acceptor has been used to obtain structural information on the protein complexes with model membranes, composed of phosphatidylcholine and cardiolipin. Analysis of experimental data in terms of the model of energy transfer in two-dimensional systems provides further evidence for preferential cytochrome c orientation with respect to the lipid bilayer and penetration of the protein into the membrane interior.

[Fluorescent energy transfer study of lysozyme complexes with liposomes]. / Issledovanie kompleksov lizotsima s liposomami metodom bezyzluchatel'nogo perenosa énergii.

The method of radiationless energy transfer was used to study the structure of lysozyme complexes with liposomes composed of phosphatidylcholine and diphosphatidylglycerol (4:3, mol:mol). 4-(n-Dimethylaminostyryl)-1-methylpyridinium n-toluenesulfonate, 4-(n-dimethylaminostyryl)-1-hexylpyridinium n-toluenesulfonate, 4-(n-dimethylaminostyryl)-1-dodecylpyridinium n-toluenesulfonate, and 3-metoxybenzanthrone were used as donors, and nile blue and rhodamine 6G, as acceptors. An increase in the surface area of model membranes upon binging of the protein to lipid bilayer was found.

[Changes in the model membrane structure induced by ribonuclease and lysozyme studied by the fluorescent probe technique]. / Izmenenie struktury model'nykh membran pod vliianiem ribonukleazy i lizotsima po dannym metoda fluorestsentnykh zondov.

Using fluorescent probes DSM and DSP-12, the effect of ribonuclease and lysozyme on the structural state of liposomes composed of phosphatidylcholine and diphosphatidylglycerol was studied. A correlation between the changes in probe quantum yield and the amount of protein-bound lipids was established. It is assumed that the formation of protein-lipid complexes increases the packing density of lipids and restricts their mobility. As the content of diphosphatidylglycerol in the lipid bilayer increases, the condensing effect of proteins becomes more pronounced.

[Kinetics of conformational changes of methemoglobin complexed with liposomes]. / Kinetika konformatsionnykh izmenenii metgemoglobina v komplekse s liposomami.

Kinetics of methemoglobin structural changes in the complex with liposomes composed of phosphatidylcholine and its mixtures with cardiolipin has been studied. The amplitudes and rate constants of the two observed kinetic phases are determined. The fast kinetic phase is attributed to the formation of the unstable intermediate protein form, while the slow one is assumed to reflect dissociation of the heme--globin complex.

[Effect of electron irradiation on the structure of microsomal membrane proteins]. / Vliianie élektronnogo oblucheniia na strukturu belkov mikrosomal'nykh membran.

Using tryptophan fluorescence quenching by iodide and acrylamide the effect of electrons with the energy 5 Mev on the structure of microsomal membrane proteins has been studied. Conformation of microsomal proteins were found to change upon irradiation.

Resonance energy transfer study of hemoglobin and cytochrome c complexes with lipids.

The complexes of hemoglobin and cytochrome c with liposomes composed of phosphatidylcholine and its mixtures with cardiolipin and cholesterol have been studied by monitoring resonance energy transfer between fluorescent probe 3-methoxybenzanthrone as donor and heme groups of the proteins as acceptors. By analyzing experimental data within the framework of the model of energy transfer in two-dimensional systems, the limits of the range of possible heme positions with respect to lipid bilayer have been assessed. The distance of heme group of hemoglobin from the membrane center was found to increase in the presence of cardiolipin or cholesterol. The results obtained for cytochrome c complexes with cardiolipin-containing model membranes suggest the existence of preferential protein orientation relative to the lipid bilayer, and provide evidence for the protein penetration in the membrane interior.

Bromothymol blue as a probe for structural changes of model membranes induced by hemoglobin.

The effect of methemoglobin on the structure of model membranes composed of phosphatidylcholine and diphosphatidylglycerol (18 : 1, mol : mol) was studied with the help of pH-indicator dye bromothymol blue. The partition coefficients characterizing the dye binding to methemoglobin or model membranes were derived from the pKaalpha dependences on the protein or phospholipid concentration. The observed character of the dye partitioning in the lipid or lipid-protein systems is interpreted in terms of the traditional electrostatic approach and some modern theories of membrane electrostatics. It is assumed that methemoglobin affects the structural and physicochemical parameters of lipid-water interface.

[Changes of liposomes electrophoretic mobility under the effect of ribonuclease and cytochrome c]. / Izmenenie elektroforeticheskoi podvizhnosti liposom pod vliianiem ribonukleasy i tsitokhroma c.

The effect of ribonuclease and cytochrome c on electrophoretic mobility of liposomes composed of phosphatidylcholine and diphosphatidylglycerol has been studied. zeta-Potential of lipid vesicles was found to decrease in the presence of proteins. Parameters of proteins binding to phospholipids were evaluated from the changes of surface charge density of model membranes. The constants of protein association with phospholipids were calculated to be about 4 x 10(4) M-1 for ribonuclease and about 5.4 x 10(4) M-1 for cytochrome c.

[Effect of ribonuclease and lysozyme on physical properties of the lipid bilayer]. / Vliianie ribonukleazy i lizotsima na fizicheskie svoistva lipidnogo bisloia.

The effect of ribonuclease and lysozyme on pyrene excimerization in liposomes composed of phosphatidylcholine and diphosphatidylglycerol has been studied. Microviscosity of bulk and annular lipids was found to increase upon the formation of lipid-protein complexes.

[Analysis of ribonuclease and lysozyme interactions with liposomes using fluorescent probes]. / Issledovanie vzaimode'istviia ribonukleasy i lizostima s liposomami metodom fluorestsentnykh zondov.

Using fluorescent probe 4-(dimethylaminostyryl)-1-methylpridine n-toluenesulfonate (DSM) the effect of ribonuslease and lysozyme on the structure of liposomes composed of phosphatidylcholine and diphosphatidylglycerol has been studied. An analysis of DSM spectra contour has been carried out and parameters of inhomogeneous broadening has been estimated. Polarity of the probe surroundings was found to decrease upon lipid-protein complexes formation.

[Effect of membranotropic agents on the activity of microsomal oxidoreductases]. / Vliianie membranotropnykh agentov na aktivnost' oksidoreduktaz mikrosom.

The effect of triton X-100 and glutaraldehyde on the functioning of microsomal oxidoreductases has been investigated. Triton X-100 was found to increase the enzymes activity. The decrease of oxidoreductases activity was observed in the presence of glutaraldehyde.

[Study of interactions of methemoglobin with liposomes using the fluorescent probe DSM and its derivatives]. / Issledovanie vzaimodeistviia metgemoglobina s liposomami s pomoshch'iu fluorestsentnogo zonda DSM i ego proizvodnykh.

Using fluorescent probes DSM, DSP-6 and DSP-12 interaction of methemoglobin with liposomes composed of phosphatidylcholine and diphosphatidylglycerol has been investigated. It was supposed that the observed decrease of probes fluorescence intensity is determined to some extent by lipids peroxidation.

[Competitive interaction of the fluorescent probe 4-(n-dimethylaminostyryl)-1-methylpyridinium n-toluolsulfonate and lysozyme with lysosomes]. / Konkurentnoe vzaimode istvie fluorestsentnogo zonda 4-(n-dimetilaminostiril)-1-metilpiridinii n-toluolsul'fonata i lizotsima s lisosomami.

Competitive binding of fluorescent probe 4-(n-dimethylaminostyryl)-1-methylpyiridinium n-toluenesulfonate and lysozyme to liposomes composed of phosphatidylcholine and diphosphatidylglycerol has been investigated. Association constants and binding stoichiometry for probe and protein have been estimated. Increase of the bilayer negative charge was found to be followed by the increase of binding constant and number of phospholipids interacting with lysozyme.

[Changes in binding parameters of fluorescent probes 1-anilinonaphthalene-8-sulfonate and 4-(n-dimethylaminostyryl)-1-methylpyridinium n-toluolsulfonate with liposomes upon radiation exposure]. / Izmenenie parametrov sviazyvaniia fluorestsentnykh zondov 1-anilinonaftalin-8-sul'fonata i 4-(n-dimetilaminostiril)-1-metilpiridinii n-toluolsul'fonata s liposomami pri vozdeistvii radiatsii.

Using fluorescent probes 1-anilinonaphthalene-8-sulfonate and 4-(n-dimethylaminostyryl)-1-methylpyridinium n-toluenesulfonate the effect of radiation on the properties of liposomes composed of phosphatidylcholine and diphosphatidylglycerol has been investigated. Parameters of the probes association with liposomes were estimated. It was suggested that radiation-induced increase of 1-anilinonaphthalene-8-sulfonate fluorescence intensity and decrease of that for 4-(n-dimethylaminostyryl)-1-methylpyridinium n-toluenesulfonate are caused by lipid's peroxidation.

[Interaction of 4-(n-dimethylaminostyryl)-1-methylpyridinium-n-toluolsulfonate with liposomes: analysis of fluorescence spectra]. / Vzaimodeistvie 4-(n-dimetilaminostiril)-1-metilpiridinii-n-toluolsul'fonata s liposomami: analiz spektrov fluorestsentsii.

Using fluorescent probe 4-(n-dimethylaminostyryl)-1-methylpyridinium n-toluenesulfonate the radiation effect on the structure of liposomes composed of phosphatidylcholine and diphosphatidylgycerol has been investigated. The from of fluorescence spectra was analyzed and inhomogeneous broadening parameters of spectral components were estimated. The polarity of DSM environment and probe distribution between different sites were found to change after irradiation.

[Study of the interaction of ribonuclease with liposomes using competitive analysis]. / Issledovanie vzaimodeistviia ribonukleazy s liposomami metodom konkurentnogo analiza.

Competitive interaction of fluorescent probe DSM and ribonuclease with liposomes composed of phosphatidylcholine and diphosphatidylglycerol mixtures has been investigated. Parameters of probe and protein binding to lipid bilayer have been estimated.

[Effect of radiation on erythrocyte membrane protein structure]. / Vliianie radiatsii na strukturu belkovogo komponenta éritrotsitarnykh membran.

Influence of the 5 MeV electron beam on the structural dynamic organization of the protein phase of erythrocyte shadows has been studied by suppression of the tryptophane fluorescence of proteins by acrylamide. It has been observed that the irradiation leads to conformation changes and increase of the structural rigidity of the protein molecules.