Kinetic stabilization of lysozyme upon interactions with β-cyclodextrin through partial unfolding

Rajabzadeh, Halimeh; Nourouzian, D; Hadi-Alijanvand, Hamid; Divsalar, Adeleh; Badraghi, Jalil; Barzegar, Abolfazl; Monajjemi, M.; Zare, Karim; Saboury, Ali Akbar; Movahedi, Ali

doi:10.1007/bf03249090

Cited by 8 publications

(6 citation statements)

References 2 publications

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“…In other words, specific ground state complexation was responsible for the quenching of the intrinsic fluorescence of LSZ in the presence of AMTH and TZ, leaving dynamic collision effects if any to be negligible. The K q values were also greater than 2.0 × 10 10 M –1 s –1 , which further testified for a static quenching mechanism. , …”

Section: Resultsmentioning

confidence: 78%

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Binding and Inhibitory Effect of the Dyes Amaranth and Tartrazine on Amyloid Fibrillation in Lysozyme

Basu

Kumar

2017

J. Phys. Chem. B

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Interaction of two food colorant dyes, amaranth and tartrazine, with lysozyme was studied employing multiple biophysical techniques. The dyes exhibited hypochromic changes in the presence of lysozyme. The intrinsic fluorescence of lysozyme was quenched by both dyes; amaranth was a more efficient quencher than tartrazine. The equilibrium constant of amaranth was higher than that of tartarzine. From FRET analysis, the binding distances for amaranth and tartrazine were calculated to be 4.51 and 3.93 nm, respectively. The binding was found to be dominated by non-polyelectrolytic forces. Both dyes induced alterations in the microenvironment surrounding the tryptophan and tyrosine residues of the protein, with the alterations being comparatively higher for the tryptophans than the tyrosines. The interaction caused significant loss in the helicity of lysozyme, the change being higher with amaranth. The binding of both dyes was exothermic. The binding of amaranth was enthalpy driven, while that of tartrazine was predominantly entropy driven. Amaranth delayed lysozyme fibrillation at 25 μM, while tartrazine had no effect even at 100 μM. Nevertheless, both dyes had a significant inhibitory effect on fibrillogenesis. The present study explores the potential antiamyloidogenic property of these azo dyes used as food colorants.

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Section: Resultsmentioning

confidence: 78%

“…The K q values were also greater than 2.0 × 10 10 M −1 s −1 , which further testified for a static quenching mechanism. 59,61 Fluorescence Lifetime Study. Lakowicz postulated that fluorescence lifetime measurements can conclusively distinguish between static and dynamic quenching processes.…”

Section: ■ Introductionmentioning

confidence: 99%

Binding and Inhibitory Effect of the Dyes Amaranth and Tartrazine on Amyloid Fibrillation in Lysozyme

Basu

Kumar

2017

J. Phys. Chem. B

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“…In that study, it was suggested that the alkaloids were bound close to the Trp-62 residue . Cyclic oligosaccharide β-cyclodextrin was reported to bind near Trp-62 and 63 residues leading to an increase in the fluorescence intensity of the protein …”

Section: Resultsmentioning

confidence: 97%

“…37 Cyclic oligosaccharide β-cyclodextrin was reported to bind near Trp-62 and 63 residues leading to an increase in the fluorescence intensity of the protein. 60 Fluorescence spectral changes of Lyz in the presence of SGRI and SGRA are illustrated in Figure 2. In both cases, increasing the concentration of the alkaloid leads to fluorescence quenching of Lyz.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Binding of the Iminium and Alkanolamine Forms of Sanguinarine to Lysozyme: Spectroscopic Analysis, Thermodynamics, and Molecular Modeling Studies

et al. 2014

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Sanguinarine (SGR) exists in charged iminium (SGRI) and neutral alkanolamine (SGRA) forms. The binding of these two forms to the protein lysozyme (Lyz) was investigated by fluorescence, UV-vis absorbance and circular dichroism spectroscopy, and in silico molecular docking approaches. Binding thermodynamics were studied by microcalorimetry. Both forms of sanguinarine quenched the intrinsic fluorescence of Lyz, but the quenching efficiencies varied on the basis of binding that was derived after correction for an inner-filter effect. The equilibrium binding constants at 25 ± 1.0 °C for the iminium and alkanolamine forms were 1.17 × 10(5) and 3.32 × 10(5) M(-1), respectively, with approximately one binding site for both forms of the protein. Conformational changes of the protein in the presence of SGR were confirmed by absorbance, circular dichroism, three-dimensional fluorescence, and synchronous fluorescence spectroscopy. Microcalorimetry data revealed that SGRI binding is endothermic and predominantly involves electrostatic and hydrophobic interactions, whereas SGRA binding is exothermic and dominated by hydrogen-bonding interactions. The molecular distances (r) of 3.27 and 3.04 nm between the donor (Lyz) and the SGRI and SGRA acceptors, respectively, were calculated according to Förster's theory. These data suggested that both forms were bound near the Trp-62/63 residues of Lyz. Stronger binding of SGRA than SGRI was apparent from the results of both structural and thermodynamic experiments. Molecular docking studies revealed that the putative binding site for the SGR analogues resides at the catalytic site. The docking results are in accordance with the spectroscopic and thermodynamic data, further validating the stronger binding of SGRA over SGRI to Lyz. The binding site is situated near a deep crevice on the protein surface and is close to several crucial amino acid residues, including Asp-52, Glu-35, Trp-62, and Trp-63. This study advances our knowledge of the structural nature and thermodynamic aspects of binding between the putative anticancer alkaloid sanguinarine and lysozyme.

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“…From Different types of catalysts can be named acidic catalyst that would have used a lot in many chemical reactions. These compounds have many applications in various chemical reactions [1][2][3][4][5][6][7] . The acid catalyst that is commonly used, are based on acids such as HF, H 2 SO 4 , HCLO 4 , H 3 PO 4 .…”

Section: Introductionmentioning

confidence: 99%

Investigation of Friedel‐Crafts Alkylation in the Presence of Supported Sulfonic Acid on Silica Gel

Kiasat

Karimi-Cheshmeali

Soleymani

et al. 2011

Journal of Chemistry

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From the Reaction between cellulose and chloro sulfonic acid was prepared sulfuric acid cellulose composition as a new solid acid. The solid acid supported on silica gel and then as an effective catalyst in Friedel-Crafts alkylation of alcohols and aromatic compounds was used. The reaction progress was controlled using thin layer chromatography and the reaction products were analyzed using IR spectroscopy devise. The results show this new catalyst is effective in the friedel crafts alkylation and C-C bond formation was done in short time with very good yields.

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Kinetic stabilization of lysozyme upon interactions with β-cyclodextrin through partial unfolding

Cited by 8 publications

References 2 publications

Binding and Inhibitory Effect of the Dyes Amaranth and Tartrazine on Amyloid Fibrillation in Lysozyme

Binding and Inhibitory Effect of the Dyes Amaranth and Tartrazine on Amyloid Fibrillation in Lysozyme

Binding of the Iminium and Alkanolamine Forms of Sanguinarine to Lysozyme: Spectroscopic Analysis, Thermodynamics, and Molecular Modeling Studies

Investigation of Friedel‐Crafts Alkylation in the Presence of Supported Sulfonic Acid on Silica Gel

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