I. M. Vlasova

Moscow State Textile University, Moskva, Moscow, Russia

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Publications (44)50.33 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The polarized fluorescence and rotational diffusion of markers of the fluorescein family (initial fluorescein and its halogenated derivatives erythrosine, eosin, and Rose Bengal) in solutions of bovine serum albumin (BSA) are studied. Elevated degrees of the polarization of fluorescence markers, increased times of rotational relaxation, and reduced coefficients of the rotational diffusion of markers are observed in solutions of BSA. It is shown that all four markers of the fluorescein family can be used to register binding with BSA, but fluorescein is better for studies of BSA with varied pH values and weakly electronegative hydrogen atoms in the structural formula. It is found that increasing the electronegativity of atoms in the structural formulas of markers raises the polarization of their fluorescence, reducing the coefficient of their rotational diffusion and lengthening their periods of rotational relaxation.
    Russian Journal of Physical Chemistry 02/2015; 89(2). DOI:10.1134/S0036024415020363 · 0.49 Impact Factor
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    ABSTRACT: The tryptophan fluorescence of bovine serum albumin (BSA) is used to study the denaturation transitions in BSA under the influence of sodium dodecyl sulfate (SDS) at various pH values. The stepwise quenching of BSA tryptophan fluorescence and the gradual increase in the degree of anisotropy of BSA tryptophan fluorescence with increasing SDS concentration in solutions indicate the stepwise nature of denaturation: the first stage is a loosening of protein globules, whereas the second is a complete unfolding of the protein amino acid chain. At pH > pI of BSA, the denaturation BSA proceeds through both stages. At pH > pI of BSA, the denaturation BSA runs poorly and stops after the first stage. A more efficient BSA denaturation under the action of SDS occurs at pH < pI of BSA, with the efficiency of BSA denaturation under the influence of SDS decreasing with increasing pH.
    Russian Journal of Physical Chemistry B 05/2014; 8(3):385-390. DOI:10.1134/S1990793114030154 · 0.34 Impact Factor
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    ABSTRACT: The rotational diffusion of bovine serum albumin (BSA) molecules in solutions with different concentrations of the anionic detergent sodium dodecylsulfate (SDS) at different pH values is investigated, yielding information on the denaturation of BSA under the action of SDS. It is found from the increased degree of polarization in the tryptophan fluorescence of BSA and the registered parameters for the rotational diffusion of BSA molecules that the denaturation of BSA under the action of SDS at pH values less than the isoelectric point (pI) of BSA (4-9) is a two-stage process. It is shown that the first stage of BSA denaturation common for all pH values is the decondensation of BSA globules, while the second stage of BSA denaturation at pH greater than the pI of BSA is the unfolding of the protein's amino acid chain. It is concluded that the denaturation of BSA under the action of SDS proceeds more deeply at pH values greater than the pI of BSA.
    Russian Journal of Physical Chemistry 02/2014; 88(3). DOI:10.1134/S003602441403025X · 0.49 Impact Factor
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    ABSTRACT: This work is dedicated to investigation of influence of different values of pH on binding of nanomarkers of fluorescein family (fluorescein, erythrosin, eosin and Bengal rose) to bovine serum albumin (BSA). For this purpose dependences of nanomarkers fluorescence, of nanomarkers molecular association, of types of chemical bonds between BSA and nanomarkers on pH are detected. The red shift of fluorescence spectra and the quenching of fluorescence of nanomarkers of fluorescein family in BSA solutions are observed. The decrease of degree of molecular association of nanomarkers in BSA solutions is found out. The dependences of fluorescence intensity and dependences of degree of molecular association on pH of halogen-derivatives of fluorescein differ dramatically from that of fluorescein.
    Journal of Molecular Structure 11/2013; 1051:86-94. DOI:10.1016/j.molstruc.2013.07.041 · 1.60 Impact Factor
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    ABSTRACT: The rotational diffusion of complexes of human serum albumin (HSA) and bovine serum albumin (BSA) with neutral surfactant Triton X-100 is study by analyzing the polarized tryptophan fluorescence and its parameters are determined (rotational relaxation time, diffusion coefficient, effective radius). Similarities in the solubilization of both proteins are revealed: an effective solubilization BSA and HSA in solutions containing neutral surfactant Triton X-100 is achieved at concentration of the latter of 0.3 mM, slightly greater than its critical micelle concentration (0.25 mM), with the most significant effect taking place at pH 5.0, a value close to the isoelectric points of the proteins.
    Russian Journal of Physical Chemistry B 09/2013; 7(5):562-567. DOI:10.1134/S1990793113050369 · 0.34 Impact Factor
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    ABSTRACT: An analysis of the molecular association and fluorescent characteristics of nanomarkers of the fluorescein family, viz., fluorescein, erythrosine, eosine, and Rose Bengal, in BSA solutions was conducted. For all the markers a decreasing degree of molecular association was observed in the BSA solutions as compared with the solutions without protein. In the solutions with BSA, fluorescence quenching and red shifting of the fluorescence spectrum maximum occurred for the solutions with BAS compared with solutions without protein for the markers of the fluorescein family. The dependences of the degree of molecular association on pH differed for fluorescein and its halogen derivatives. The efficiency dependences of nanomarker binding with BSA on pH differed for fluorescein and its halogen derivatives.
    Moscow University Physics Bulletin 07/2013; 68(4):304-310. DOI:10.3103/S0027134913040097 · 0.20 Impact Factor
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    ABSTRACT: The tryptophan fluorescence of bovine serum albumin (BSA) in solutions with different concentrations of cationic detergent cetyltrimethylammonium bromide (CTAB) at different pH is investigated, providing information on BSA denaturation under the action of CTAB. It is found that BSA denaturation under the action of CTAB at all of the investigated pH values (3.5–8.0) is a single-stage process, as determined by BSA tryptophan fluorescence quenching, by an increased degree of the BSA tryptophan fluorescence polarization, and by the values of the parameters for the rotational diffusion of BSA molecules in CTAB solutions. It is shown that the cationic detergent CTAB is more efficient for BSA denaturation at pH values higher than the BSA isoelectric point (4.9).
    Russian Journal of Physical Chemistry 06/2013; 87(6). DOI:10.1134/S0036024413060319 · 0.49 Impact Factor
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    ABSTRACT: The polarized fluorescence of the Rose Bengal fluorescent nanomarker in HSA solutions was investigated and parameters of its rotational diffusion were calculated. The increase in the degree of fluorescence polarization, rotational relaxation time, and the effective hydrodynamic radius of Rose Bengal, as well as the decrease of the rotational diffusion coefficient in HSA solutions, were found. The effects of the electronegativity of atoms in the structure of the nanomarker on the parameters of its rotational diffusion were established based on comparison of Rose Bengal with other nanomarkers of the homologous family.
    Moscow University Physics Bulletin 05/2013; 68(3). DOI:10.3103/S0027134913030119 · 0.20 Impact Factor
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    ABSTRACT: The interaction of cationic surfactant cethyltrimethylammonium bromide (CTAB) with bovine serum albumin (BSA) at various values of pH has been studied using steady-state non-polarized tryptophan fluorescence of BSA and polarized tryptophan fluorescence of BSA. By analysis of intensity of tryptophan fluorescence of BSA, by analysis of position of maximum of spectrum of BSA tryptophan fluorescence, by analysis of polarization of BSA tryptophan fluorescence the qualitative rearrangements of BSA globules at denaturation under action of CTAB are registered. The estimation of parameters of rotational diffusion of BSA molecules helps one to determine the quantitative changes of size of BSA at CTAB-induced denaturation. It is shown that denaturation of BSA, taking place at interaction of cationic surfactant CTAB with BSA, has one-stage mono-phase character. At interaction of CTAB with BSA the deepest denaturation of BSA is reached at 4 mM CTAB (at pH 3.5–8.0). More intensive denaturation of BSA under action of CTAB takes place at values of pH, higher than the isoelectric point of BSA.
    Journal of Molecular Structure 02/2013; 1034:89–94. DOI:10.1016/j.molstruc.2012.08.053 · 1.60 Impact Factor
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    ABSTRACT: The interaction of fluorescent marker Bengal Rose with human serum albumin (HSA) at various values of pH has been studied by steady-state fluorescence, absorption spectroscopy, and Raman spectroscopy. The decrease of degree of molecular association of Bengal Rose in solutions at HSA addition is revealed. It is shown that degree of molecular association of Bengal Rose monotonously decreases with increase of values of pH. It is registered that in solutions with HSA there are quenching of fluorescence and red shift of maximum of fluorescence spectrum of Bengal Rose. Various theoretical models are used to determine the constants of quenching of fluorescence of Bengal Rose by HSA, corresponding to binding of Bengal Rose to HSA molecules, at various values of pH. It is shown that binding of Bengal Rose with HSA takes place through Binding Center I of HSA. The received results of researches of interaction of Bengal Rose with HSA show the perspectives of this marker in structural researches of HSA and in modeling of binding of some medical drugs to HSA.
    Journal of Molecular Structure 05/2012; 1016:1–7. DOI:10.1016/j.molstruc.2012.02.008 · 1.60 Impact Factor
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    ABSTRACT: Denaturation of human serum albumin (HSA) under the action of cationic detergent cetyltrimethylammonium bromide (CTAB) is studied at different pH values by estimating the rotational diffusion of protein via fluorescence polarization. The degree of polarization of HSA tryptophan fluorescence, the rotational relaxation time, the rotational diffusion coefficient and the effective Einstein radius of the HSA molecules in solutions with different CTAB concentrations at different pH values are determined. The obtained rotational diffusion parameters of the HSA molecules show that under the action of CTAB, HSA denaturation has a one-stage character and proceeds more intensely and effectively at pH values higher than the pI value of protein (4.7).
    Russian Journal of Physical Chemistry 03/2012; 86(3). DOI:10.1134/S0036024412030338 · 0.49 Impact Factor
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    ABSTRACT: Using three models, the constant of quenching of fluorescence of nanomarkers of the fluorescein family and the actual constants of its binding to human serum albumin (HSA) at different values of pH are determined. The presence of two mechanisms of binding of nanomarkers of the fluorescein family to HSA and anti-cooperativity are shown. The dependence of the constants of the quenching fluorescence of nanomarkers on pH was found: for fluorescein this was nonlinear, for its halogen derivatives (erythsosine, eosin, and Rose Bengal) it was monotonous and decreased with an increase of pH. It is shown that the electronegativity of the atoms in the structural formulas of nanomarkers of the fluorescein family influences the values of the constants of binding of nanomarkers to HSA.
    Moscow University Physics Bulletin 03/2012; 67(2). DOI:10.3103/S002713491202018X · 0.20 Impact Factor
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    ABSTRACT: The decrease in the degree of molecular association of the Rose Bengal nanomarker in solutions with the addition of human serum albumin (HSA) has been revealed. It has been observed that in solutions with the addition of HSA the fluorescence quenching and the shifting of the fluorescence spectrum peaks of Rose Bengal to the red take place. It has been shown that the dependence of the effective binding constant of binding Rose Bengal to HSA steadily decreases with an increase in the pH value. It has been established that the values of the molecular association degree of Rose Bengal and the values of the effective constant of its binding to HSA depend on the magnitude of the electronegativity of the atoms in its structural formula, as well as on the pK values of its ionizable groups.
    Moscow University Physics Bulletin 10/2011; 66(5). DOI:10.3103/S0027134911050183 · 0.20 Impact Factor
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    ABSTRACT: This work is dedicated to investigation of interaction of nanomarkers of fluorescein family (initial composition – fluorescein and its halogens-derivatives – erythrosin and eosin) with human serum albumin (HSA) at different values of pH. Were detected differences in polarization of fluorescence of nanomarkers, in parameters of rotational diffusion of nanomarkers, in binding mechanisms of nanomarkers to HSA, in change of secondary structure of HSA at binding of nanomarkers, in effective Stern–Volmer constants of quenching of fluorescence of nanomarkers, which are determinated by value of electronegativity of atoms of nanomarkers. The increase of electronegativity of atoms in nanomarkers leads to increase of polarization of its fluorescence, to decrease of its coefficient of rotational diffusion, to increase of its time of rotational relaxation, to increase of Einstein’s effective radius of nanomarkers, to decrease of effective Stern–Volmer constants of quenching of fluorescence of nanomarkers in range from pI of HSA (4.7) to physiological pH (7.4).Highlights► The interaction of nanomarkers of fluorescein family with HSA is investigated. ► Electronegativity of atoms of nanomarkers effects on fluorescence of nanomarkers. ► Electronegativity of atoms of nanomarkers effects on its rotational diffusion. ► The binding mechanism of nanomarkers to HSA is investigated. ► The Stern–Volmer constants of nanomarkers in HSA solutions are determinated.
    Current Applied Physics 09/2011; 11(5):1126-1132. DOI:10.1016/j.cap.2011.02.004 · 2.03 Impact Factor
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    ABSTRACT: Rotational diffusion of fluorescein family nanomarkers (initial fluorescein and its halogenated derivatives, eosin and erythrosine) in solutions of human serum albumin (HSA) was studied at various pH values. In solutions of HSA, the degree of fluorescence polarization, rotational relaxation time, and Einstein radius of nanomarkers are larger and the rotational diffusion coefficient of nanomarkers smaller than in solutions without the protein. An increase in the electronegativity of atoms in the structural formulas of nanomarkers increases the degree of polarization of their fluorescence, decreases the coefficient of their rotational diffusion, and increases rotational relaxation time and the effective Einstein radius.
    Russian Journal of Physical Chemistry 05/2011; 85(5). DOI:10.1134/S0036024411050323 · 0.49 Impact Factor
  • I. M. Vlasova, A. M. Saletsky
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    ABSTRACT: An analysis of the intrinsic fluorescence of the protein and the fluorescence of the eosin molecular probe in solutions of the protein was used to study the denaturation of human serum albumin (HSA) under the action of cetyltrimethylammonium bromide (CTAB), a cationic detergent, at various pH values. The denaturation of HSA under the influence of CTAB is a single-stage process over the entire pH range covered, pH (3.5–8.0). The maximum possible loosening of HSA globules in the presence of CTAB is reached at [CTAB] = 4 mmol/l. This detergent effectively denatures HSA at pH values higher than the pI of the protein (4.7). Keywordshuman serum albumin–denaturation–fluorescence–probe–eosin
    Russian Journal of Physical Chemistry B 04/2011; 5(2):320-325. DOI:10.1134/S1990793111020400 · 0.34 Impact Factor
  • I. M. Vlasova, A. M. Saletsky
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    ABSTRACT: Polarized tryptophan fluorescence of human serum albumin (HSA) was analyzed to determine the parameters of rotational diffusion (rotational relaxation time, rotational diffusion coefficient, and the effective Einstein radius) of HSA molecules during denaturation under the action of sodium dodecyl sulfate (SDS). Two stages of HSA denaturation under the action of SDS were shown: (1) loosening of protein globules and (2) unfolding of the amino-acid chain of the protein. HSA denaturation under the action of SDS is a two-stage process at pH values lower than the pI of HAS but passes through stage 1 only at pH values higher than the pI.
    Moscow University Physics Bulletin 02/2011; 66(1). DOI:10.3103/S0027134911010218 · 0.20 Impact Factor
  • I. M. Vlasova, A. M. Saletsky
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    ABSTRACT: The mechanism of denaturation of human serum albumin (HSA) under action of a cationic detergent—cethyltrimethylammonium bromide (CTAB) is investigated by Raman spectroscopy method. The percentage contents of α-helical segments in polypeptide chain of HSA at denaturation under action of different concentrations of CTAB at different values of pH is determined. It is shown, that more intensive denaturation of HSA under action of CTAB takes place at pH values, larger the isoelectric point of protein (pI 4.7).
    Laser Physics 01/2011; 21(1):239-244. DOI:10.1134/S1054660X10230131 · 1.03 Impact Factor
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    ABSTRACT: The interaction of cationic detergent cethyltrimethylammonium bromide (CTAB) with human serum albumin (HSA) at various values of pH has been studied using steady-state tryptophan fluorescence of HSA, polarized tryptophan fluorescence of HSA, fluorescence of nanomarker eosin in solutions of HSA and CTAB and Raman spectroscopy. By methods of fluorescent analysis the qualitative rearrangements of HSA globules at denaturation under action of CTAB are registered, whereas by Raman spectroscopy the quantitative changes of secondary structure of HSA at CTAB-induced denaturation are determined. It is shown that denaturation of HSA, taking place at interaction of cationic detergent CTAB with HSA, has one-stage character. At interaction of CTAB with HSA the deepest denaturation of HSA is reached at concentration of 4 mM CTAB (in the range of pH 3.5–8.0). More intensive denaturation of HSA under action of CTAB takes place at values of pH, higher than the isoelectric point of HSA (pI 4.7).
    Journal of Molecular Structure 12/2010; 984(1-3):332-338. DOI:10.1016/j.molstruc.2010.09.051 · 1.60 Impact Factor
  • I. M. Vlasova, A. M. Saletsky
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    ABSTRACT: The influence of binding of nanomarkers of fluorescein family to HSA on secondary structure of this protein at different values of pH was investigated by Raman spectroscopy method. The greatest changes in secondary structure of HSA, consisting in decreasing of alpha-helix sites, at binding of fluorescein to HSA occur at pH 5-6. The greatest changes in secondary structure of HSA, consisting in decreasing of alpha-helix sites, at binding of eosin or erythrosin to HSA take place at values of pH, smaller 5. The differences in changes in secondary structure of HSA at binding of these three nanomarkers are explained by dependences of binding of nanomarkers to HSA on pH which determined by value of electronegativity of atoms of lateral radicals in structural formulas of nanomarkers and, therefore, by value of pK of their ionized groups.
    Laser Physics 09/2010; 20:1844-1848. DOI:10.1134/S1054660X10170160 · 1.03 Impact Factor

Publication Stats

282 Citations
50.33 Total Impact Points

Institutions

  • 2015
    • Moscow State Textile University
      Moskva, Moscow, Russia
  • 2004–2013
    • Lomonosov Moscow State University
      • • Division of Physics
      • • Department of Biophysics at the Faculty of Physics
      • • Faculty of Physics
      Moskva, Moscow, Russia
  • 2004–2012
    • Moscow State Forest University
      Mytishi, Moskovskaya, Russia