The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Boris I. Kurganov - One of the best experts on this subject based on the ideXlab platform.
-
Effect of arginine on staBility and aggregation of muscle <B>GlycogenB> <B>PhosphorylaseB> B.
International journal of biological macromolecules, 2020Co-Authors: Tatiana B. Eronina, Natalia A. Chebotareva, Valeriya V. Mikhaylova, Sergey Yu. Kleymenov, V. V. Shubin, Boris I. KurganovAbstract:Arginine (Arg) is frequently used in Biotechnology and pharmaceutics to staBilize protein preparations. When using charged ions like Arg, it is necessary to take into account their contriBution to the increase in ionic strength, in addition to the effect of Arg on particular processes occurring under the conditions of constancy of ionic strength. Here, we examined contriBution of ionic strength (0.15 and 0.5 M) to the effects of Arg on denaturation, thermal inactivation and aggregation of skeletal muscle <B>GlycogenB> <B>PhosphorylaseB> B (PhB). Dynamic light scattering, analytical ultracentrifugation, differential scanning calorimetry, circular dichroism and enzymatic activity assay were used to assess the effects of Arg at constant ionic strength compared with the effects of ionic strength alone. We found that high ionic strength did not affect the secondary structure of PhB, But changed conformation of the protein. Such a destaBilization of the enzyme causes an increase in the initial rate of aggregation and inactivation of PhB thereBy affecting its denaturation. Binding of Arg causes additional changes in the protein conformation, weakening the Bonds Between monomers in the dimer. This causes the dimer to dissociate into monomers, which rapidly aggregate. Thus, Arg acts on these processes much stronger than just ionic strength.
-
Comparative effects of trehalose and 2-hydroxypropyl-β-cyclodextrin on aggregation of UV-irradiated muscle <B>GlycogenB> <B>PhosphorylaseB> B.
Biochimie, 2019Co-Authors: Tatiana B. Eronina, Natalia A. Chebotareva, Valeriya V. Mikhaylova, V. V. Shubin, Nikolai N. Sluchanko, Boris I. KurganovAbstract:Chemical chaperones are a class of small molecules which enhance folding and prevent aggregation of proteins. Investigation of their effects on the processes of protein aggregation is of importance for further understanding of implication of protein aggregation in neurodegenerative diseases, as well as for solving Biotechnological tasks. The effects of chemical chaperones trehalose and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) on the kinetics of aggregation of UV-irradiated muscle <B>GlycogenB> <B>PhosphorylaseB> B (UV-PhB) at 37 °C have Been studied. The process of thermal aggregation of UV-PhB includes a slow stage of structural reorganization of the UV-PhB molecule, nucleation stage and fast attachment of structurally reorganized UV-PhB molecules to nuclei formed during the nucleation stage. It was shown that Both trehalose and HP-β-CD increased the duration of the nucleation phase and slowed down the rate of structural reorganization of the UV-PhB molecule. This conclusion has Been confirmed By the circular dichroism data. In the aBsence of chaperones, 82% UV-PhB aggregates, whereas in the presence of HP-β-CD or trehalose the portion of aggregated protein decreases to 70 and 66%, respectively. The data on analytical ultracentrifugation demonstrated that in the presence of these additives the size of protein aggregates decreased. Analysis of the comBined effect of trehalose and HP-β-CD on UV-PhB aggregation showed that protein aggregation was independently affected By trehalose and HP-β-CD.
-
Effect of ionic strength and arginine on aggregation of UV-irradiated muscle <B>GlycogenB> <B>PhosphorylaseB> B
International journal of biological macromolecules, 2018Co-Authors: Tatiana B. Eronina, Natalia A. Chebotareva, Valeriya V. Mikhaylova, V. V. Shubin, Boris I. KurganovAbstract:In this work the effect of ionic strength and arginine on the kinetics of aggregation of UV-irradiated muscle <B>GlycogenB> <B>PhosphorylaseB> B (UV-PhB) was studied using dynamic light scattering at 37 °C at various ionic strengths (0.02-0.7 M). Under these conditions the rate-limiting stage of the overall aggregation process is the structural reorganization of UV-PhB, which can Be characterized By the first order rate constant kI. It was shown that an increase in NaCl concentration caused a decrease in the kI value, suggesting a slowdown of the UV-PhB structural reorganization. Circular dichroism data confirmed this conclusion. Arginine is widely used in Biotechnology as an agent suppressing protein aggregation. However, arginine is a charged molecule, and, when studying the action of arginine on protein aggregation, the effects of ionic strength should Be taken into account. To evaluate the effect of arginine, experiments were conducted at fixed values of ionic strength (0.15 M and 0.5 M). It was shown that at a low ionic strength arginine (0-0.13 M) accelerated the process of protein aggregation, whereas at higher ionic strength arginine (0-0.48 M) acted as an aggregation suppressor.
-
A thermal after-effect of UV irradiation of muscle <B>GlycogenB> <B>PhosphorylaseB> B
PloS one, 2017Co-Authors: Valeriya V. Mikhaylova, Natalia A. Chebotareva, Tatiana B. Eronina, Sergey Yu. Kleymenov, V. V. Shubin, Boris I. KurganovAbstract:Different test systems are used to characterize the anti-aggregation efficiency of molecular chaperone proteins and of low-molecular-weight chemical chaperones. Test systems Based on aggregation of UV-irradiated protein are of special interest Because they allow studying the protective action of different agents at physiological temperatures. The kinetics of UV-irradiated <B>GlycogenB> <B>PhosphorylaseB> B (UV-PhB) from raBBit skeletal muscle was studied at 37°C using dynamic light scattering in a wide range of protein concentrations. It has Been shown that the order of aggregation with respect to the protein is equal to unity. A conclusion has Been made that the rate-limiting stage of the overall process of aggregation is heat-induced structural reorganization of a UV-PhB molecule, which contains concealed damage.
-
Mechanism of aggregation of UV-irradiated <B>GlycogenB> <B>PhosphorylaseB> B at a low temperature in the presence of crowders and trimethylamine N-oxide.
Biophysical chemistry, 2017Co-Authors: Tatiana B. Eronina, Natalia A. Chebotareva, Valeriya V. Mikhaylova, Vera A. Borzova, Igor K. Yudin, Boris I. KurganovAbstract:To characterize the initial stages of protein aggregation, the kinetics of aggregation of UV-irradiated <B>GlycogenB> <B>PhosphorylaseB> B (UV-PhB) was studied under conditions when the aggregation proceeded at a low rate (10°C, 0.03M Hepes Buffer, pH6.8, containing 0.1M NaCl). Aggregation of UV-PhB was induced By polyethylene glycol and Ficoll-70, acting as crowders, or a natural osmolyte trimethylamine N-oxide (TMAO). It has Been shown that the initial rate of the stage of aggregate growth is proportional to the protein concentration squared, suggesting that the order of aggregation with respect to the protein is equal to two. It has Been concluded that the aggregation mechanism of UV-PhB at 10°C in the presence of crowders includes the nucleation stage and stages of protein aggregate growth (the Basic aggregation pathway). The aggregation mechanism is complicated in the presence of TMAO, and the stage of aggregate-aggregate assemBly induced By TMAO should Be added to the Basic aggregation pathway. It has Been shown that the aBility of TMAO at a low concentration (0.05M) to induce aggregation of UV-PhB is due to the decrease in the aBsolute value of zeta potential of the protein in the presence of TMAO.
Natalia A. Chebotareva - One of the best experts on this subject based on the ideXlab platform.
-
Effect of arginine on staBility and aggregation of muscle <B>GlycogenB> <B>PhosphorylaseB> B.
International journal of biological macromolecules, 2020Co-Authors: Tatiana B. Eronina, Natalia A. Chebotareva, Valeriya V. Mikhaylova, Sergey Yu. Kleymenov, V. V. Shubin, Boris I. KurganovAbstract:Arginine (Arg) is frequently used in Biotechnology and pharmaceutics to staBilize protein preparations. When using charged ions like Arg, it is necessary to take into account their contriBution to the increase in ionic strength, in addition to the effect of Arg on particular processes occurring under the conditions of constancy of ionic strength. Here, we examined contriBution of ionic strength (0.15 and 0.5 M) to the effects of Arg on denaturation, thermal inactivation and aggregation of skeletal muscle <B>GlycogenB> <B>PhosphorylaseB> B (PhB). Dynamic light scattering, analytical ultracentrifugation, differential scanning calorimetry, circular dichroism and enzymatic activity assay were used to assess the effects of Arg at constant ionic strength compared with the effects of ionic strength alone. We found that high ionic strength did not affect the secondary structure of PhB, But changed conformation of the protein. Such a destaBilization of the enzyme causes an increase in the initial rate of aggregation and inactivation of PhB thereBy affecting its denaturation. Binding of Arg causes additional changes in the protein conformation, weakening the Bonds Between monomers in the dimer. This causes the dimer to dissociate into monomers, which rapidly aggregate. Thus, Arg acts on these processes much stronger than just ionic strength.
-
Comparative effects of trehalose and 2-hydroxypropyl-β-cyclodextrin on aggregation of UV-irradiated muscle <B>GlycogenB> <B>PhosphorylaseB> B.
Biochimie, 2019Co-Authors: Tatiana B. Eronina, Natalia A. Chebotareva, Valeriya V. Mikhaylova, V. V. Shubin, Nikolai N. Sluchanko, Boris I. KurganovAbstract:Chemical chaperones are a class of small molecules which enhance folding and prevent aggregation of proteins. Investigation of their effects on the processes of protein aggregation is of importance for further understanding of implication of protein aggregation in neurodegenerative diseases, as well as for solving Biotechnological tasks. The effects of chemical chaperones trehalose and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) on the kinetics of aggregation of UV-irradiated muscle <B>GlycogenB> <B>PhosphorylaseB> B (UV-PhB) at 37 °C have Been studied. The process of thermal aggregation of UV-PhB includes a slow stage of structural reorganization of the UV-PhB molecule, nucleation stage and fast attachment of structurally reorganized UV-PhB molecules to nuclei formed during the nucleation stage. It was shown that Both trehalose and HP-β-CD increased the duration of the nucleation phase and slowed down the rate of structural reorganization of the UV-PhB molecule. This conclusion has Been confirmed By the circular dichroism data. In the aBsence of chaperones, 82% UV-PhB aggregates, whereas in the presence of HP-β-CD or trehalose the portion of aggregated protein decreases to 70 and 66%, respectively. The data on analytical ultracentrifugation demonstrated that in the presence of these additives the size of protein aggregates decreased. Analysis of the comBined effect of trehalose and HP-β-CD on UV-PhB aggregation showed that protein aggregation was independently affected By trehalose and HP-β-CD.
-
Effect of ionic strength and arginine on aggregation of UV-irradiated muscle <B>GlycogenB> <B>PhosphorylaseB> B
International journal of biological macromolecules, 2018Co-Authors: Tatiana B. Eronina, Natalia A. Chebotareva, Valeriya V. Mikhaylova, V. V. Shubin, Boris I. KurganovAbstract:In this work the effect of ionic strength and arginine on the kinetics of aggregation of UV-irradiated muscle <B>GlycogenB> <B>PhosphorylaseB> B (UV-PhB) was studied using dynamic light scattering at 37 °C at various ionic strengths (0.02-0.7 M). Under these conditions the rate-limiting stage of the overall aggregation process is the structural reorganization of UV-PhB, which can Be characterized By the first order rate constant kI. It was shown that an increase in NaCl concentration caused a decrease in the kI value, suggesting a slowdown of the UV-PhB structural reorganization. Circular dichroism data confirmed this conclusion. Arginine is widely used in Biotechnology as an agent suppressing protein aggregation. However, arginine is a charged molecule, and, when studying the action of arginine on protein aggregation, the effects of ionic strength should Be taken into account. To evaluate the effect of arginine, experiments were conducted at fixed values of ionic strength (0.15 M and 0.5 M). It was shown that at a low ionic strength arginine (0-0.13 M) accelerated the process of protein aggregation, whereas at higher ionic strength arginine (0-0.48 M) acted as an aggregation suppressor.
-
A thermal after-effect of UV irradiation of muscle <B>GlycogenB> <B>PhosphorylaseB> B
PloS one, 2017Co-Authors: Valeriya V. Mikhaylova, Natalia A. Chebotareva, Tatiana B. Eronina, Sergey Yu. Kleymenov, V. V. Shubin, Boris I. KurganovAbstract:Different test systems are used to characterize the anti-aggregation efficiency of molecular chaperone proteins and of low-molecular-weight chemical chaperones. Test systems Based on aggregation of UV-irradiated protein are of special interest Because they allow studying the protective action of different agents at physiological temperatures. The kinetics of UV-irradiated <B>GlycogenB> <B>PhosphorylaseB> B (UV-PhB) from raBBit skeletal muscle was studied at 37°C using dynamic light scattering in a wide range of protein concentrations. It has Been shown that the order of aggregation with respect to the protein is equal to unity. A conclusion has Been made that the rate-limiting stage of the overall process of aggregation is heat-induced structural reorganization of a UV-PhB molecule, which contains concealed damage.
-
Mechanism of aggregation of UV-irradiated <B>GlycogenB> <B>PhosphorylaseB> B at a low temperature in the presence of crowders and trimethylamine N-oxide.
Biophysical chemistry, 2017Co-Authors: Tatiana B. Eronina, Natalia A. Chebotareva, Valeriya V. Mikhaylova, Vera A. Borzova, Igor K. Yudin, Boris I. KurganovAbstract:To characterize the initial stages of protein aggregation, the kinetics of aggregation of UV-irradiated <B>GlycogenB> <B>PhosphorylaseB> B (UV-PhB) was studied under conditions when the aggregation proceeded at a low rate (10°C, 0.03M Hepes Buffer, pH6.8, containing 0.1M NaCl). Aggregation of UV-PhB was induced By polyethylene glycol and Ficoll-70, acting as crowders, or a natural osmolyte trimethylamine N-oxide (TMAO). It has Been shown that the initial rate of the stage of aggregate growth is proportional to the protein concentration squared, suggesting that the order of aggregation with respect to the protein is equal to two. It has Been concluded that the aggregation mechanism of UV-PhB at 10°C in the presence of crowders includes the nucleation stage and stages of protein aggregate growth (the Basic aggregation pathway). The aggregation mechanism is complicated in the presence of TMAO, and the stage of aggregate-aggregate assemBly induced By TMAO should Be added to the Basic aggregation pathway. It has Been shown that the aBility of TMAO at a low concentration (0.05M) to induce aggregation of UV-PhB is due to the decrease in the aBsolute value of zeta potential of the protein in the presence of TMAO.
Christopher M. Dobson - One of the best experts on this subject based on the ideXlab platform.
-
solid state 31p cross polarization magic angle sample spinning nuclear magnetic resonance studies of crystalline <B>GlycogenB> <B>PhosphorylaseB> B
Biophysical Journal, 1993Co-Authors: Jocelyn E. Taguchi, Stephen J. Heyes, David Barford, L N Johnson, Christopher M. DobsonAbstract:31 P cross-polarization/magic angle sample spinning nuclear magnetic resonance spectra have Been oBtained for pyridoxal 5′-phosphate (PLP) Bound to <B>GlycogenB> <B>PhosphorylaseB> B (GPB) in two different crystalline forms, monoclinic and tetragonal. Analysis of the intensities of the spinning sideBands in the nuclear magnetic resonance spectra has enaBled estimates of the principal values of the 31 P chemical shift tensors to Be oBtained. Differences Between the two sets of values suggest differences in the environment of the phosphate moiety of the pyridoxal phosphate in the two crystalline forms. The tensor for the tetragonal crystalline form, T state GPB, is fully consistent with those found for dianionic phosphate groups in model compounds. The spectrum for the monoclinic crystalline form, R state GPB, although closer to that of dianionic than monoanionic model phosphate compounds, deviates significantly from that expected for a simple dianion or monoanion. This is likely to result from specific interactions Between the PLP phosphate group and residues in its Binding site in the protein. A possiBle explanation for the spectrum of the monoclinic crystals is that the shift tensor is averaged By a proton exchange process Between different ionization states of the PLP associated with the presence of a sulfate ion Bound in the vicinity of the PLP.
-
Solid state 31P cross-polarization/magic angle sample spinning nuclear magnetic resonance studies of crystalline <B>GlycogenB> <B>PhosphorylaseB> B
Biophysical journal, 1993Co-Authors: Jocelyn E. Taguchi, Louise N. Johnson, Stephen J. Heyes, David Barford, Christopher M. DobsonAbstract:31 P cross-polarization/magic angle sample spinning nuclear magnetic resonance spectra have Been oBtained for pyridoxal 5′-phosphate (PLP) Bound to <B>GlycogenB> <B>PhosphorylaseB> B (GPB) in two different crystalline forms, monoclinic and tetragonal. Analysis of the intensities of the spinning sideBands in the nuclear magnetic resonance spectra has enaBled estimates of the principal values of the 31 P chemical shift tensors to Be oBtained. Differences Between the two sets of values suggest differences in the environment of the phosphate moiety of the pyridoxal phosphate in the two crystalline forms. The tensor for the tetragonal crystalline form, T state GPB, is fully consistent with those found for dianionic phosphate groups in model compounds. The spectrum for the monoclinic crystalline form, R state GPB, although closer to that of dianionic than monoanionic model phosphate compounds, deviates significantly from that expected for a simple dianion or monoanion. This is likely to result from specific interactions Between the PLP phosphate group and residues in its Binding site in the protein. A possiBle explanation for the spectrum of the monoclinic crystals is that the shift tensor is averaged By a proton exchange process Between different ionization states of the PLP associated with the presence of a sulfate ion Bound in the vicinity of the PLP.
Jocelyn E. Taguchi - One of the best experts on this subject based on the ideXlab platform.
-
solid state 31p cross polarization magic angle sample spinning nuclear magnetic resonance studies of crystalline <B>GlycogenB> <B>PhosphorylaseB> B
Biophysical Journal, 1993Co-Authors: Jocelyn E. Taguchi, Stephen J. Heyes, David Barford, L N Johnson, Christopher M. DobsonAbstract:31 P cross-polarization/magic angle sample spinning nuclear magnetic resonance spectra have Been oBtained for pyridoxal 5′-phosphate (PLP) Bound to <B>GlycogenB> <B>PhosphorylaseB> B (GPB) in two different crystalline forms, monoclinic and tetragonal. Analysis of the intensities of the spinning sideBands in the nuclear magnetic resonance spectra has enaBled estimates of the principal values of the 31 P chemical shift tensors to Be oBtained. Differences Between the two sets of values suggest differences in the environment of the phosphate moiety of the pyridoxal phosphate in the two crystalline forms. The tensor for the tetragonal crystalline form, T state GPB, is fully consistent with those found for dianionic phosphate groups in model compounds. The spectrum for the monoclinic crystalline form, R state GPB, although closer to that of dianionic than monoanionic model phosphate compounds, deviates significantly from that expected for a simple dianion or monoanion. This is likely to result from specific interactions Between the PLP phosphate group and residues in its Binding site in the protein. A possiBle explanation for the spectrum of the monoclinic crystals is that the shift tensor is averaged By a proton exchange process Between different ionization states of the PLP associated with the presence of a sulfate ion Bound in the vicinity of the PLP.
-
Solid state 31P cross-polarization/magic angle sample spinning nuclear magnetic resonance studies of crystalline <B>GlycogenB> <B>PhosphorylaseB> B
Biophysical journal, 1993Co-Authors: Jocelyn E. Taguchi, Louise N. Johnson, Stephen J. Heyes, David Barford, Christopher M. DobsonAbstract:31 P cross-polarization/magic angle sample spinning nuclear magnetic resonance spectra have Been oBtained for pyridoxal 5′-phosphate (PLP) Bound to <B>GlycogenB> <B>PhosphorylaseB> B (GPB) in two different crystalline forms, monoclinic and tetragonal. Analysis of the intensities of the spinning sideBands in the nuclear magnetic resonance spectra has enaBled estimates of the principal values of the 31 P chemical shift tensors to Be oBtained. Differences Between the two sets of values suggest differences in the environment of the phosphate moiety of the pyridoxal phosphate in the two crystalline forms. The tensor for the tetragonal crystalline form, T state GPB, is fully consistent with those found for dianionic phosphate groups in model compounds. The spectrum for the monoclinic crystalline form, R state GPB, although closer to that of dianionic than monoanionic model phosphate compounds, deviates significantly from that expected for a simple dianion or monoanion. This is likely to result from specific interactions Between the PLP phosphate group and residues in its Binding site in the protein. A possiBle explanation for the spectrum of the monoclinic crystals is that the shift tensor is averaged By a proton exchange process Between different ionization states of the PLP associated with the presence of a sulfate ion Bound in the vicinity of the PLP.
Tatiana B. Eronina - One of the best experts on this subject based on the ideXlab platform.
-
Effect of arginine on staBility and aggregation of muscle <B>GlycogenB> <B>PhosphorylaseB> B.
International journal of biological macromolecules, 2020Co-Authors: Tatiana B. Eronina, Natalia A. Chebotareva, Valeriya V. Mikhaylova, Sergey Yu. Kleymenov, V. V. Shubin, Boris I. KurganovAbstract:Arginine (Arg) is frequently used in Biotechnology and pharmaceutics to staBilize protein preparations. When using charged ions like Arg, it is necessary to take into account their contriBution to the increase in ionic strength, in addition to the effect of Arg on particular processes occurring under the conditions of constancy of ionic strength. Here, we examined contriBution of ionic strength (0.15 and 0.5 M) to the effects of Arg on denaturation, thermal inactivation and aggregation of skeletal muscle <B>GlycogenB> <B>PhosphorylaseB> B (PhB). Dynamic light scattering, analytical ultracentrifugation, differential scanning calorimetry, circular dichroism and enzymatic activity assay were used to assess the effects of Arg at constant ionic strength compared with the effects of ionic strength alone. We found that high ionic strength did not affect the secondary structure of PhB, But changed conformation of the protein. Such a destaBilization of the enzyme causes an increase in the initial rate of aggregation and inactivation of PhB thereBy affecting its denaturation. Binding of Arg causes additional changes in the protein conformation, weakening the Bonds Between monomers in the dimer. This causes the dimer to dissociate into monomers, which rapidly aggregate. Thus, Arg acts on these processes much stronger than just ionic strength.
-
Comparative effects of trehalose and 2-hydroxypropyl-β-cyclodextrin on aggregation of UV-irradiated muscle <B>GlycogenB> <B>PhosphorylaseB> B.
Biochimie, 2019Co-Authors: Tatiana B. Eronina, Natalia A. Chebotareva, Valeriya V. Mikhaylova, V. V. Shubin, Nikolai N. Sluchanko, Boris I. KurganovAbstract:Chemical chaperones are a class of small molecules which enhance folding and prevent aggregation of proteins. Investigation of their effects on the processes of protein aggregation is of importance for further understanding of implication of protein aggregation in neurodegenerative diseases, as well as for solving Biotechnological tasks. The effects of chemical chaperones trehalose and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) on the kinetics of aggregation of UV-irradiated muscle <B>GlycogenB> <B>PhosphorylaseB> B (UV-PhB) at 37 °C have Been studied. The process of thermal aggregation of UV-PhB includes a slow stage of structural reorganization of the UV-PhB molecule, nucleation stage and fast attachment of structurally reorganized UV-PhB molecules to nuclei formed during the nucleation stage. It was shown that Both trehalose and HP-β-CD increased the duration of the nucleation phase and slowed down the rate of structural reorganization of the UV-PhB molecule. This conclusion has Been confirmed By the circular dichroism data. In the aBsence of chaperones, 82% UV-PhB aggregates, whereas in the presence of HP-β-CD or trehalose the portion of aggregated protein decreases to 70 and 66%, respectively. The data on analytical ultracentrifugation demonstrated that in the presence of these additives the size of protein aggregates decreased. Analysis of the comBined effect of trehalose and HP-β-CD on UV-PhB aggregation showed that protein aggregation was independently affected By trehalose and HP-β-CD.
-
Effect of ionic strength and arginine on aggregation of UV-irradiated muscle <B>GlycogenB> <B>PhosphorylaseB> B
International journal of biological macromolecules, 2018Co-Authors: Tatiana B. Eronina, Natalia A. Chebotareva, Valeriya V. Mikhaylova, V. V. Shubin, Boris I. KurganovAbstract:In this work the effect of ionic strength and arginine on the kinetics of aggregation of UV-irradiated muscle <B>GlycogenB> <B>PhosphorylaseB> B (UV-PhB) was studied using dynamic light scattering at 37 °C at various ionic strengths (0.02-0.7 M). Under these conditions the rate-limiting stage of the overall aggregation process is the structural reorganization of UV-PhB, which can Be characterized By the first order rate constant kI. It was shown that an increase in NaCl concentration caused a decrease in the kI value, suggesting a slowdown of the UV-PhB structural reorganization. Circular dichroism data confirmed this conclusion. Arginine is widely used in Biotechnology as an agent suppressing protein aggregation. However, arginine is a charged molecule, and, when studying the action of arginine on protein aggregation, the effects of ionic strength should Be taken into account. To evaluate the effect of arginine, experiments were conducted at fixed values of ionic strength (0.15 M and 0.5 M). It was shown that at a low ionic strength arginine (0-0.13 M) accelerated the process of protein aggregation, whereas at higher ionic strength arginine (0-0.48 M) acted as an aggregation suppressor.
-
A thermal after-effect of UV irradiation of muscle <B>GlycogenB> <B>PhosphorylaseB> B
PloS one, 2017Co-Authors: Valeriya V. Mikhaylova, Natalia A. Chebotareva, Tatiana B. Eronina, Sergey Yu. Kleymenov, V. V. Shubin, Boris I. KurganovAbstract:Different test systems are used to characterize the anti-aggregation efficiency of molecular chaperone proteins and of low-molecular-weight chemical chaperones. Test systems Based on aggregation of UV-irradiated protein are of special interest Because they allow studying the protective action of different agents at physiological temperatures. The kinetics of UV-irradiated <B>GlycogenB> <B>PhosphorylaseB> B (UV-PhB) from raBBit skeletal muscle was studied at 37°C using dynamic light scattering in a wide range of protein concentrations. It has Been shown that the order of aggregation with respect to the protein is equal to unity. A conclusion has Been made that the rate-limiting stage of the overall process of aggregation is heat-induced structural reorganization of a UV-PhB molecule, which contains concealed damage.
-
Mechanism of aggregation of UV-irradiated <B>GlycogenB> <B>PhosphorylaseB> B at a low temperature in the presence of crowders and trimethylamine N-oxide.
Biophysical chemistry, 2017Co-Authors: Tatiana B. Eronina, Natalia A. Chebotareva, Valeriya V. Mikhaylova, Vera A. Borzova, Igor K. Yudin, Boris I. KurganovAbstract:To characterize the initial stages of protein aggregation, the kinetics of aggregation of UV-irradiated <B>GlycogenB> <B>PhosphorylaseB> B (UV-PhB) was studied under conditions when the aggregation proceeded at a low rate (10°C, 0.03M Hepes Buffer, pH6.8, containing 0.1M NaCl). Aggregation of UV-PhB was induced By polyethylene glycol and Ficoll-70, acting as crowders, or a natural osmolyte trimethylamine N-oxide (TMAO). It has Been shown that the initial rate of the stage of aggregate growth is proportional to the protein concentration squared, suggesting that the order of aggregation with respect to the protein is equal to two. It has Been concluded that the aggregation mechanism of UV-PhB at 10°C in the presence of crowders includes the nucleation stage and stages of protein aggregate growth (the Basic aggregation pathway). The aggregation mechanism is complicated in the presence of TMAO, and the stage of aggregate-aggregate assemBly induced By TMAO should Be added to the Basic aggregation pathway. It has Been shown that the aBility of TMAO at a low concentration (0.05M) to induce aggregation of UV-PhB is due to the decrease in the aBsolute value of zeta potential of the protein in the presence of TMAO.