Examinando por Autor "Laguta, Anna"

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Association of novel monomethine cyanine dyes with bacteriophage MS2: A fluorescence study
(Elsevier, 2020-03-15) Vus, Kateryna; Tarabara, Uliana; Balklava, Zita; Nerukh, Dmitry; Stich, Michael; Laguta, Anna; Vodolazkaya, Natalya; Mchedlov-Petrossyan, Nikolay O.; Farafonov, Vladimir; Kriklya, Nika; Gorbenko, Galyna; Trusova, Valeriya; Zhytniakivska, Olga; Kurutos, Atanas; Gadjev, Nikolai; Deligeorgiev, Todor
Novelmonomethine cyanine dyes Cl-YO, F-YO, Cl-YO-Et, Cl-YO-Bu, and YO-Pent were evaluated as agents to detect and characterise a small virus, the MS2 bacteriophage, using the dye and virus intrinsic fluorescence, kinetic and thermal properties, chemical denaturation, and molecular docking and quantum chemistry modelling. The examined compounds demonstrated enhanced fluorescence responses and high affinities (~1 μM−1) for the intact bacteriophage at physiological ionic strength. The linear Scatchard plots revealed the existence of one binding mode for most dyes. Strong evidence that the cyanines bind to the bacteriophage external surface were obtained, although the possibility of the dye penetration through the virus shell and subsequent complexation with the viral RNA was also tested. The main arguments in favour of the former were that i) the fluorescence of theMS2-bound fluorophores decreased under the influence of protein denaturants, urea and guanidine hydrochloride; ii) the fluorescence responses of the dyes toMS2 and bovine serumalbumin were similar; and (iii) one order of magnitude higher sensitivity of the dyes to the yeast RNA was found. Simple docking studies suggested that one cyaninemolecule is trapped in a cleft formed by three proteins composing the virus shell. Significant role of electrostatic forces in the stabilisation of the dye-MS2 complexes at low ionic strength (10 mM) was demonstrated, while the influence of steric, hydrophobic, and van-der-Waals interactions was expected to increase at physiological ionic strength. The spectral properties of the novel cyanine dyes compared to other fluorophores demonstrated higher sensitivity of the cyanines to MS2, rendering them promising agents for the investigation of the changes in the virus structure under the influence of heat (Cl-YO-Et, Cl-YO-Bu), denaturants (Cl-YO, FYO), and ionic strength (all the compounds).
Estimation of Nanoparticle’s Surface Electrostatic Potential in Solution Using Acid−Base Molecular Probes. III. Experimental Hydrophobicity/Hydrophilicity and Charge Distribution of MS2 Virus Surface
(American Chemical Society, 2022-10-05) Vodolazkaya, Natalya; Nikolskaya, Marina; Laguta, Anna; Farafonov, Vladimir; Balklava, Zita; Stich, Michael; Mchedlov-Petrossyan, Nikolay; Nerukh, Dmitry
MS2 bacteriophage is often used as a model for evaluating pathogenic viruses’ behaviour in aqueous solution. However, the questions of the virus surface’s hydrophilic/hydrophobic balance, the charge distribution, and the binding mechanism are open. Using dynamic light scattering method and laser Doppler electrophoresis the hydrodynamic diameter and the zeta-potential of the virus particles were measured at their concentration of 5x10^11 particles per mL and ionic strength 0.03 M. The values were found to be 30 nm and −29 or −34 mV (by Smoluchowski or Ohshima approximations) respectively. MS2 bacteriophage surface was also investigated using a series of acid-base indicator dyes of various charge type, size, and structure. Their spectral and acid-base properties (pKa) are very sensitive to microenvironment in aqueous solution including containing nano-particles. The electrostatic potential of the surface Ψ was estimated using the common formula: Ψ =59x(pKa^i − pKa) in mV at 25 °C. The Ψ values were −50 mV and +10 mV respectively, which indicate the ‘mosaic’ way of the charge distribution on the surface. These data are in good agreement with the obtained zeta-potential values and provide even more information about the virus surface. It was found that the surface of the MS2 virus is hydrophilic in solution in contrast to commonly accepted hypothesis of hydrophobicity of virus particles. No hydrophobic interactions between various molecular probes and the capsid were observed.
Influence of various colloidal surfactants on the stability of MS2 bacteriophage suspension. The charge distribution on the PCV2 virus surface
(Elsevier, 2023-10-01) Vodolazkaya, Natalya; Laguta, Anna; Farafonov, Vladimir; Nikolskaya, Marina; Balklava, Zita; Khayat, Reza; Stich, Michael; Mchedlov-Petrossyan, Nikolay; Nerukh, Dmitry
To understand virus stability in aqueous solutions, the colloidal nanostructure and properties of a model virus, the MS2 bacteriophage, have been investigated by studying the effect of the addition of electrolytes and various colloidal surfactants to its water solution at physiological conditions. The charge of the virus particles influences their colloidal properties. It was found that the ζ-potential value is reduced from –35 mV to –10 mV in 0.01 M CaCl2 and 0.1 M NaCl solutions as well as at higher electrolytes concentrations, while the size of the MS2 aggregates was about 600 ÷ 900 nm with individual particles of size around 30 nm also recorded. The 2 : 1 electrolyte causes destabilization of MS2 bacteriophage particles in an aqueous solution at a lower concentration. The addition of cationic, anionic, and non-ionic colloidal surfactants below and above critical micelle concentration to MS2 bacteriophage suspension caused the destabilization of MS2 particles. We also investigated the capsid’s surface of another virus, PCV2, using dynamic light scattering and laser Doppler electrophoresis. The hydrodynamic diameter and the ζ-potential of PCV2 empty capsid were found to be equal to 22 ± 1 nm and -41± 4 mV (using Ohshima approximations). The electrostatic potential of the surface was measured using acid-base probes and found to be equal to -91 ± 3 and +14 ± 2 mV for positively and negatively charged probes respectively, which indicate the ‘mosaic’ way of the charge distribution on the surface, similar to MS2′s surface studied previously. Our data provide new information about the virus surface, the complex process of virus aggregation-disaggregation and virus capsid disassembly.