Measuring nanolayer profiles of various materials by evanescent light technique.

The evanescent light photon extraction efficiency of insulator, semiconductor and conductor amorphous nanolayers deposited on glass waveguides was evaluated from Differential Evanescent Light Intensity measurements. The Differential Evanescent Light Intensity technique uses the evanescent field scattered by the deposited nanolayer, enabling nanometer thickness profiling due to the high inherent dark background contrast. The results show that the effective evanescent photon penetration depth increases from metal to semiconductor and then to insulating layers, establishing thus the effective photon-material interaction length for the various materials classes.

[Catalysis of 'dark' stage of cis-trans-isomerization of betaine stilbazole by myoglobin]. / Kataliz "temnovoi" stadii reaktsii tsis-trans-izomerizatsii betaina stil'bazola mioglobinom.

The back thermal cis-trans isomerization reaction of stilbazole betaine in the presence of metmyoglobin was studied. The catalytic effect of metmyoglobin heme on the back thermal cis-trans isomerization reaction of stilbazole betaine was observed.

[Effect of molecular dynamics on the photoinduced electron transfer in eosin-myoglobin complex]. / Vliianie molekuliarnoi dinamiki na fotoindutsirovannyi perenos électrona v komplekse éosin-mioglobin.

The temperature dependence of the rate constant of photoinduced electron transfer in the modified eosin-myoglobin complex by monitoring of the phosphorescence quenching of eosin is measured. The values of electron transfer rate constants are equal 10(2) + 10(3) s-1 in the temperature region 150-200 K. The kinetics of relaxation of the maximum of the time-resolved phosphorescence spectra of eosin on apomyoglobin is measured in the same temperature range. The solvation relaxation of the time-resolved phosphorescence spectra is nonexponential. The characteristic times of the solvation relaxation are given 10(-2) + 10(-4) s-1, that correlate with the time of electron transfer in this system. It was observed the "acceleration" of the relaxation rate of the time-resolved phosphorescence spectra of eosin in metmyoglobin due to nonequilibrium photoinduced electron transfer. The role of the matrix dynamics in photoinduced electron transfer in proteins is discussed.

[Analysis of experimental data on kinetics of electron transfer in metal-containing proteins and within the framework of an adiabatic approach]. / Analiz éksperimental'nykh dannykh po kinetike perenosa élektrona v metallsoderzhashchikh belkakh v ramkakh adiabaticheskogo priblizheniia.

Conception of the microsecond intramolecular protein dynamics with wide distribution of relaxation times is used for interpretation of published data on electron transfer kinetics in natural and chemically modified proteins. This is the evidence not only the unit static structure, but the dynamical organization of proteins as high organized molecular systems.

Haem localization in haemoproteins by spin and triplet tools.

The rate constants of efficient exchange interaction (kex) of spin-labelled lysozyme and the triplet probes perylene, eosine and anthracene butanoic acid with the haemoproteins were measured in microsomes and in solution by electron paramagnetic resonance and by the registration of delayed annihilation fluorescence. Constants of efficient exchange interactions with the haem groups of myoglobin, haemoglobin, cytochrome c and b5 are 3-22 X 10(7) M-1 s-1 in solution. The experiments with membrane-bound cytochrome P-450 revealed no exchange interactions with the probes located in solution or in the membrane. These results can be accounted for by the deeper incorporation of cytochrome P-450 haem into the protein globule as compared to the other haemoprotein haems studied.

[Quantitative estimate of major factors determining the kinetics of electron transfer reactions with cytochrome c]. / Kolichestvennaia otsenka osnovnykh faktorov, opredeliaiushchikh kinetiku reaktsii élektronnogo perenosa s uchastiem tsitokhroma c.

Quantitative estimation of basic factors determining the electron transfer rate constant between cytochrome c and inorganic metal complexes and electron exchange rate constant based on the theory of nonadiabatic electron transfer in polar media is presented.

[Phosphorescence quenching in evaluation of the steric interactions of heme-containing proteins]. / Ispol'zovanie tusheniia fosforestsentsii dlia otsenki prostranstvennykh vzaimodeistvii gemsoderzhashchikh belkov.

The rate constants of exchange phosphorescence quenching of eosin by ferricyanide, hemin and hem-proteins (cytochrome c, myoglobin , hemoglobin, leghemoglobin) are measured. The steric factor of hem of cytochrome c is evaluated from the constant of eosin phosphorescence quenching by cytochrome c.

[Intramolecular dynamics and electron transfer in photosynthetic reaction centers. A study using luminescence]. / Vnutrimolekuliarnaia dinamika i perenos élektrona v fotosinteticheskikh reaktsionnykh tsentrakh. Issledovanie metodom liuminestsentsii.

The temperature dependences of fluorescence and phosphorescence spectra maxima of chromophor labels--endogenic (tryptophan) and exogenic (eosinisothiocyanate)--were measured for the preparations of photosynthetic membranes and reaction centers from Rhodospirillum rubrum. It was found that the dipole mobility of protein-lipid matrix in the vicinity of the chromophores intensified markedly with a temperature rise from 150 to 300K resulting in the corresponding relaxation time tau r decrease from 10(0) to 10(-8) s. The efficiency of direct transfer of the photomobilized electron in the system of quinone acceptors (A1- leads to A2) of reaction centers (characteristic half-times of the process being 10(-3) divided by 10(-4) s) was shown also to increase sharply at temperatures higher than 200K parallel to the enhancement of molecular motions with tau r approximately 10(-8) s. Meanwhile, changes observed in the rate of recombination of primary photoproducts, i.e. an oxidized bacteriochlorophyll dimer, P+ and a reduced acceptor, A1- (characteristic half-time of 10(-1) divided by 10(-2) s) and the activization of low-frequency motions with tau r approximately 10(-3) s in the external layers and tau r less than 1 s in the internal parts of the reaction centers protein develop over the same range of low temperatures (150-220 K). The nature of interactions which determine the dependence of the photosynthetic electron transport on the molecular mobility of the membrane proteins is discussed.

[Structure and intramolecular dynamics of a photoactive pigment-protein eosin-casein complex]. / Issledovanie struktury i vnutrimolekuliarnoi dinamiki fotoaktivnogo pigment-belkovogo kompleksa eozin-kazein.

The structure of eosin--casein complex was studied by triplet label method. Quantitative data on the quantum--mechanic exchange interaction between eosin centres and external quenchers were obtained. The dynamic state of water--protein matrix at -20 degrees to -180 degrees C with eosin as fluorescence and phosphorescence labels and natural chromophores of protein--tryptophane was studied.

[Use of triplet state exchange disactivation phenomenon for the study of structure and electron conductivity of proteins]. / Ispol'zovanie iavleniia obmennoi dezaktivatsii tripletnykh vozbuzhdennykh sostoianii dlia issledovaniia stroeniia i élektronnoi provodimosti belkov.

A method for studying protein structure and estimating its electron conducting properties is proposed. The method is based on the kinetic recording of exchange quenching triplet labels and probes phosphorescence by chromophores or paramagnetic centres. It is shown that different types of exchange interactions (spin exchange, exchange energy transfer) between centres with distance R are described approximately by an equation (I = I0 exp-2R/L) where L changes from 0.7 A (absence of electron coupling--system of type I) to 6.5 A (strong electron coupling--system of type II). I (sec-1) corresponds to exchange energy transfer rate constant or exchange integral in the case of spin exchange. Life-times of excited triplet state eosin-isotiocionate labels connected with the terminal NH2-groups of the following preparations were measured by the method of kinetic phosphorescence decay recording: human oxyhemoglobin, methemoglobin, F- and CN-methemoglobin, metmyoglobin, F- and CN-metmyoglobins. The influence of lysozyme of the nitroxyl spin label bound to His-15 group on the phosphorescence spectrum was investigated. The analysis of our and literature data on the exchange interactions between the centres localized on the protein with known structure (hemoglobin, myoglobin, lysozyme, carboangidrase, bacterial ferredoxin) permit us to conclude that in the examined cases the experimental values correspond to model systems of type I and are different from the dependence in systems of type II by 5--15 order. This allows us to use equation (I) for estimation of the distances between the centres on proteins.

[Investigation of the microstructure of biological systems by triplet label]. / Issledovanie mikrostruktury biologicheskikh sistem metodom tripletkh metok.

A method for investigating the microstruct and dynamics of biological systems by means of triplet-excited molecules is suggested. The method is based on the phenomenon of triplet excitation disactivation by exchange-resonance triplet-triplet energy transfer to the acceptor or by intercombination conversion induced by interaction of an excited molecule with a paramagnetic center. The disactivation efficiency was measured by registrating the phosphorescense decay kinetics. The interaction of the triplet label eosin isothiocyanate, covalently coupled with albumine, lysozyme, sarcoplasmic reticulum membrane and Ca-Mg-dependent sarcoplasmic reticulum ATPase, with O2, the stable nitroxide radicals and ions of Mn2+ was investigated to analyse the potentialities of this method. As a model system the eosin phosphorescence quenching by the same quenchers in glycerine-aguaous solutions was studied. The method permits to investigate the microviscosity and microstructure of biological objects in the label attached region on interaction of the label with a sound-quencher with constants being 10(4) divided by 10(9) M-1 sec-1 and to measure the lateral diffusion of molecules in highly viscosity media (10 divided by 10(5) santypuas).