Browsing by Author "Ivoylov, I."

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    Dielectric relaxation, molecular motion and interprotein interactions in myoglobin solution.
    (Taylor and Francis, 1997) Ermolina, I.; Ivoylov, I.; Fedotov,V.
    The results of the investigation of protein molecule dynamic in solution by Time Domain Dielectric Spectroscopy are presented. The horse myoglobin solutions in wide range of concentration from 0.6% to 54% at 20°C have been investigated. The result of analysis produced in the term of dipole correlation function has shown that the obtained correlation function of macromolecule motion may be presented as sum of three components corresponding to three kinds of protein motions: anisotropic intramolecular motion, anisotropic Brownian tumbling and isotropic slow motion. We suppose that the cause of protein tumbling anisotropy and the possibility to keep slow motion is the interprotein electrostatic interactions. The characteristic time of slow motion depends on the concentration of protein and perhaps is controlled by translational diffusion. The dipole moment of myoglobin calculated by the Onsager-Oncley equation is 200D for solutions less than 10% protein concentration. It is in a good agreement with the theoretical value.
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    Investigation of molecular motion and interprotein interactions in solutions by TDDS: A comparison with NMR data
    (Elsevier, 1994-09-01) Ermolina, I.; Fedotov,V.; Feldman, Yuri; Ivoylov, I.
    The results of dynamic protein behavior in solution studied by time domain dielectric spectroscopy (TDDS) are presented. The analyses for myoglobin solutions at concentrations 50, 120 and 150 mg/ml in the temperature interval from 5 to 35°C was carried out in terms of dipole correlation functions. It was found that the correlation function of the protein motion can be presented as a sum of three components corresponding to three types of protein motion: internal local motion, anisotropy otational Brownian diffusion and translational Brownian diffusion. According to the hypothesis presented earlier, it is supposed that the reason for anisotropy of protein rotation and capability for the detection translational diffusion (slowest motion) is the mutual interprotein electrostatic steering.
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    Investigation of molecular motions and interprotein interactions in solutions by NMR and TDDS.
    (Springer, 1993) Ermolina, I.; Krushelnitsky, A. G.; Ivoylov, I.; Feldman, Yuri; Fedotov, V.
    Non-selective NMR relaxation of protein and water protons at various resonance frequencies as well as Time Domain Dielectric Spectroscopy (TDDS) were applied to study the molecular motions in lysozyme and myoglobin solutions. It was found that the correlation function of the protein motion defined by means of all these methods can be presented as a sum of three components having substantially different correlation times. Both NMR and TDDS experimental data were treated on the basis of approach according to which these components of the correlation function correspond to three different kinds of protein motion, namely 1) internal local motion, 2) anisotropic rotational Brownian diffusion and 3) translational Brownian diffusion. According to the hypothesis proposed earlier we suppose that the reason of anisotropy of protein rotation and possibility to detect experimentally the slowest motion (translational diffusion) is the mutual interprotein electrostatic steering. The qualitative consistency between parameters of correlation function obtained from NMR and TDDS and their concentration dependence confirm the validity of the qualitative model of the interprotein electrostatic interactions.