Comparative Analysis of KP-HSA Complex by Spectroscopic Methods

Maciążek-Jurczyk, Małgorzata; Równicka-Zubik, J.; Dyja, Renata; Sułkowska, Anna

doi:10.12693/aphyspola.123.673

Cited by 12 publications

(6 citation statements)

References 35 publications

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“…These curves show negative deviation from linearity, mainly in the higher concentration range of indomethacin, and concave towards the x-axis. This phenomenon usually happens when there is more than one tryptophan residue with a distinct environment and different accessibility to the quencher [ 45 , 49 , 50 ], but it is well known that HSA has only one tryptophan residue located in the subdomain IIA, thus, there is a possibility of the existence of more than one binding site for indomethacin inside HSA [ 51 ], and the larger distance of secondary binding site in comparison to the primary one reduced the quenching efficiency, thus, a negative deviation in the Stern–Volmer plots could be expected [ 52 , 53 , 54 ]. Silva and coworkers have suggested that the binding of a ligand to the HSA may lead to the possible conformational change followed by the exposition of lower affinity binding sites [ 55 ].…”

Section: Resultsmentioning

confidence: 99%

Detailed Experimental and In Silico Investigation of Indomethacin Binding with Human Serum Albumin Considering Primary and Secondary Binding Sites

et al. 2023

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The interaction of indomethacin with human serum albumin (HSA) has been studied here considering the primary and secondary binding sites. The Stern–Volmer plots were linear in the lower concentration range of indomethacin while a downward curvature was observed in the higher concentration range, suggesting the presence of more than one binding site for indomethacin inside HSA due to which the microenvironment of the fluorophore changed slightly and some of its fraction was not accessible to the quencher. The Stern–Volmer quenching constants (KSV) for the primary and secondary sites were calculated from the two linear portions of the Stern–Volmer plots. There was around a two-fold decrease in the quenching constants for the low-affinity site as compared to the primary binding site. The interaction takes place via a static quenching mechanism and the KSV decreases at both primary and secondary sites upon increasing the temperature. The binding constants were also evaluated, which show strong binding at the primary site and fair binding at the secondary site. The binding was thermodynamically favorable with the liberation of heat and the ordering of the system. In principle, hydrogen bonding and Van der Waals forces were involved in the binding at the primary site while the low-affinity site interacted through hydrophobic forces only. The competitive binding was also evaluated using warfarin, ibuprofen, hemin, and a warfarin + hemin combination as site markers. The binding profile remained unchanged in the presence of ibuprofen, whereas it decreased in the presence of both warfarin and hemin with a straight line in the Stern–Volmer plots. The reduction in the binding was at a maximum when both warfarin and hemin were present simultaneously with the downward curvature in the Stern–Volmer plots at higher concentrations of indomethacin. The secondary structure of HSA also changes slightly in the presence of higher concentrations of indomethacin. Molecular dynamics simulations were performed at the primary and secondary binding sites of HSA which are drug site 1 (located in the subdomain IIA of the protein) and the hemin binding site (located in subdomain IB), respectively. From the results obtained from molecular docking and MD simulation, the indomethacin molecule showed more binding affinity towards drug site 1 followed by the other two sites.

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Section: Resultsmentioning

confidence: 99%

Detailed Experimental and In Silico Investigation of Indomethacin Binding with Human Serum Albumin Considering Primary and Secondary Binding Sites

et al. 2023

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“…It points to the dynamic mechanism of quenching. At higher concentrations, positive deviation from linearity suggests a more complex quenching process, probably an additional presence of a static component in the quenching mechanism [ 60 , 61 ]. From the linear part of a regression, F 0 /F versus [c] the K SV constant 2 × 10 4 M −1 was calculated.…”

Section: Resultsmentioning

confidence: 99%

Investigation of the Interaction between Mechanosynthesized ZnS Nanoparticles and Albumin Using Fluorescence Spectroscopy

Lukáčová Bujňáková,

Dutková,

Jakubíková

et al. 2023

Pharmaceuticals

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In this paper, ZnS nanoparticles were bioconjugated with bovine serum albumin and prepared in a form of nanosuspension using a wet circulation grinding. The stable nanosuspension with monomodal particle size distribution (d50 = 137 nm) and negative zeta potential (−18.3 mV) was obtained. The sorption kinetics and isotherm were determined. Interactions between ZnS and albumin were studied using the fluorescence techniques. The quenching mechanism, describing both static and dynamic interactions, was investigated. Various parameters were calculated, including the quenching rate constant, binding constant, stoichiometry of the binding process, and accessibility of fluorophore to the quencher. It has been found that tryptophan, in comparison to tyrosine, can be closer to the binding site established by analyzing the synchronous fluorescence spectra. The cellular mechanism in multiple myeloma cells treated with nanosuspension was evaluated by fluorescence assays for quantification of apoptosis, assessment of mitochondrial membrane potential and evaluation of cell cycle changes. The preliminary results confirm that the nontoxic nature of ZnS nanoparticles is potentially applicable in drug delivery systems. Additionally, slight changes in the secondary structure of albumin, accompanied by a decrease in α-helix content, were investigated using the FTIR method after analyzing the deconvoluted Amide I band spectra of ZnS nanoparticles conjugated with albumin. Thermogravimetric analysis and long-term stability studies were also performed to obtain a complete picture about the studied system.

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“…ANS is an extrinsic fluorescent probe with low fluorescent quantum yield in water, but it becomes much brighter in nonpolar solvents or after adsorption onto proteins with exposed hydrophobic portions . ANS can be used to study the binding properties of hydrophobic molecules onto protein because the fluorescence of ANS provides information on all of the hydrophobic binding sites of HSA . Changes in PSH monitored by ANS can be calculated by the following equation :

PSH = \frac{F_{max}}{[HSA] K_{d}^{app}}

where F max is the maximum fluorescence intensity at the saturated ANS concentration, which indicates the number of surface hydrophobic sites of HSA.…”

Section: Resultsmentioning

confidence: 99%

“…

K_{d}^{app}

is the apparent dissociation constant of ANS to HSA, and 1/

K_{d}^{app}

is the binding affinity of the ANS–HSA complex . F max and 1/

K_{d}^{app}

can be calculated by the Scatchard equation :

\frac{F}{{[ANS]}_{f r e e}} = - \frac{F}{K_{d}^{app}} + \frac{F_{max}}{K_{d}^{a p p}}

where [ANS] free is the concentration of free ANS and can be obtained from the difference between the total and bound concentration of ANS as follows :

The concentration of bound ANS can be calculated by the following equation :

{[ANS]}_{bound} = \frac{F}{B}

B can be obtained using the method of Cardamone and Puri , which assumed that a linear relationship exists between fluorescence intensity ( F ) and ANS concentration (c) ( F = B c ) in very dilute solutions of ANS (0–2.0 μM).…”

Section: Resultsmentioning

confidence: 99%

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Investigation on the Interaction of Norgestrel with Human Serum Albumin Using Spectroscopy and Molecular‐Docking Method

Wang

et al. 2016

J Biochem & Molecular Tox

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The interaction of norgestrel with human serum albumin (HSA) was investigated by spectroscopy and molecular-docking methods. Results of spectroscopy methods suggested that the quenching mechanism of norgestrel on HSA was static quenching and that the quenching process was spontaneous. Negative values of thermodynamic parameters (ΔG, ΔH, and ΔS) indicated that hydrogen bonding and van der Waals forces dominated the binding between norgestrel and HSA. Three-dimensional fluorescence spectrum and circular dichroism spectrum showed that the HSA structure was slightly changed by norgestrel. Norgestrel mainly bound with Sudlow site I based on a probe study, as confirmed by molecular-docking results. Competition among similar structures indicated that ethisterone and norethisterone affected the binding of norgestrel with HSA. CH3 in R1 had little effect on norgestrel binding with HSA. The surface hydrophobicity properties of HSA, investigated using 8-anilino-1-naphthalenesulfonic acid, was changed with norgestrel addition.

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Comparative Analysis of KP-HSA Complex by Spectroscopic Methods

Cited by 12 publications

References 35 publications

Detailed Experimental and In Silico Investigation of Indomethacin Binding with Human Serum Albumin Considering Primary and Secondary Binding Sites

Detailed Experimental and In Silico Investigation of Indomethacin Binding with Human Serum Albumin Considering Primary and Secondary Binding Sites

Investigation of the Interaction between Mechanosynthesized ZnS Nanoparticles and Albumin Using Fluorescence Spectroscopy

Investigation on the Interaction of Norgestrel with Human Serum Albumin Using Spectroscopy and Molecular‐Docking Method

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