Interaction Of Bovine Serum Albumin Research Articles

Exploring albumin-sulfonephthalein dyes interactions by a chemometric-assisted and multi-technique equilibria analysis in solution

Albumin is undoubtedly the most studied protein thanks to its widespread diffusion and biochemistry; despite its binding ability towards different dyes, provoking dye’s colour change, has been exploited for decades for quantification purposes, the joint effect of working pH, ionic strength, and dye’s pKa still remains only sporadically discussed. In the present study, the interaction of Bovine Serum Albumin (BSA) with five dyes belonging to the sulfonephthalein group, Bromophenol Blue (BPB, pKa = 3.75), Bromocresol Green (BCG, pKa = 4.42), Chlorophenol Red (CPR, pKa = 5.74), Bromocresol Purple (BCP, pKa = 6.05) and Bromothymol Blue (BTB, pKa = 6.72), is investigated at four working pH values (3.5, 6.0, 7.5 and 9.0) and two ionic strength conditions by UV–Vis spectroscopy. Principal Component Analysis is then applied to rationalize dye behavior upon BSA addition at each pH value and to summarize the protein effect on dyes’ spectral features, identifying three general behaviors. The most relevant systems are then submitted to further characterization involving a solution equilibria study aimed at determining conditional binding constants for the selected DSA-dye adducts and fluorescence, CD, and 1H NMR spectroscopy to evaluate the binding effect on the species involved.

Effect of irradiated nonionic surfactant on drug-protein binding

In this work, the effect of γ-irradiated surfactants on drug–protein binding has been assessed. Irradiated aqueous solutions of Pluronic F-127, Pluronic L-35, Tween 20, and Tween 80 surfactants were used. Gamma irradiation was carried out for three different doses, to these four surfactants viz., 6, 30, and 36 kGy. Two drugs, Ornidazole (ONZ) and Telmisartan (TMS) were used for the binding study. The effect of four irradiated surfactants in the presence of drug – Bovine serum albumin (BSA) protein was analyzed. The drug solutions in methanol-aqueous media were combined with BSA in the initial step. In the next two succeeding steps, drug–BSA interaction in the presence of unirradiated and irradiated surfactants were carried out. The results of drug-BSA due to addition of irradiated and unirradiated surfactants were compared. The interaction processes were assessed through UV Spectroscopy, DLS, zeta potential, turbidity, and docking studies. Improved binding was observed for both the drugs and four surfactants for irradiated surfactants as determined from the binding constant values using UV spectroscopic studies. The DLS measurements demonstrated no general trend of increase or decrease in micellar size with absorbed dose. The binding and change in the size of micelles were observed to be highly drug and surfactant-specific. Among the four surfactants, irradiated Pluronic F-127 showed higher binding affinity. To the best of our knowledge, this is the first report on the effect of γ-irradiated surfactant on drug–BSA interaction. This can be applied to other drug–protein systems to tune their interaction to the required level. Communicated by Ramaswamy H. Sarma

Clarifying the role of carboxyl functionality in squaraines towards aggregation and self-assembly through photophysical characterization and BSA interactions

The demand for near-infrared (NIR) probes with robust and stable fluorescence signals has surged, driven by their applications in optical sensing and bioimaging. Squraine dyes as NIR fluorescent probes have gained significant traction. However, understanding their behavior in aqueous media is important for their successful application. Herein we report the synthesis and photophysical characterization of carboxy-functionalized unsymmetrical squaraine dyes capable of light absorption and emission in the near-infrared (NIR) wavelength region. Structural variations in alkyl chain length, and spacer chain length between the primary chromophore and –COOH group were systematically introduced to investigate their impact on self-assembly in aqueous media leading to dye aggregation and their differential interactions with Bovine Serum Albumin (BSA) as a model protein. In phosphate buffer (PB) the absorption intensity decreased drastically along with pronounced shoulders due to dye aggregation leading to complete fluorescence quenching. However, in the presence of BSA, the intensity of shoulder bands reduced coupled with a sharp increase in the absorption associated with monomeric dye with the increasing concentration of BSA, indicating the prevention of dye aggregation owing to dye-BSA interactions. The prevention of dye aggregation due to dye-BSA interaction also led to a tremendous increase in the fluorescence intensities as a function of the increasing BSA concentrations. Site-selective study off BSA showed that these dyes bind preferably at Site-II using hydrophilic interactions. Thus, these dyes show great potential as FRET or fluorescent on/off probes for biosensing, non-covalent labeling of proteins, and fluorescent probes for bioimaging.

Unveiling the antimicrobial potency and binding interaction between sulfonamide substituted Schiff’s bases and BSA protein: An integrated experimental and theoretical approach

Sulfonamide derived Schiff’s bases encompass significant properties such as antifungal, anti-inflammatory, anticancer, antibacterial, antiproliferative, and antioxidant and hold a central position in therapeutics and diagnostics. Hence, it is essential to comprehend their interconnection with carrier proteins such as Bovine serum albumin (BSA). Herein, two different sulfonamide derived Schiff’s base derivatives,N'-(2,5-Dimethoxybenzylidene)-4-methylbenzenesulfonohydrazide SB-1 and N'-(3-Bromo-4-methoxybenzylidene)-4-methylbenzenesulfonohydrazide SB-2 were synthesized by reacting respectivealdehydes with p-toluenesulfonyl hydrazide as the amine counterpart in absolute ethanol and structurally characterized by FT-IR,1H and13C NMR, elemental analyses, thermogravimetric analysis (TGA), mass spectrometry and single-crystal X-ray crystallography. The binding interactions between BSA andSB-1 and SB-2were made by employing UV–vis. absorption and fluorescence spectroscopy. Information about the binding constant was obtained from the absorbance enhancement and fluorescence quenching of BSA in the presence ofSB-1 and SB-2respectively. However, the binding efficiency ofSB-1was found to be superior to that of BSA in comparison toSB-2. The antibacterial potential ofSB-1 and SB-2 wastested on E. coliandS. aureus using thewell diffusion method.In silicoADME properties forSB-1 and SB-2were checked to assess their stability. The binding mechanisms to the specific enzymes associated with the BSA interaction and the antibacterial capabilities of theSB-1 and SB-2were further supported by molecular docking calculations. The detailed studies provide comprehensive data to support the utility of prepared Schiff’s bases as potential biomarkers in therapeutics.

Synthesis, characterization, and BSA binding studies of newfangled 2-phenylacetohydrazide derivatives

Five 2-phenylacetohydrazide derivatives (BPAH = N′-benzylidene-2-phenylacetohydrazide, HBPAH = N’-(2-hydroxybenzylidene)-2-phenylacetohydrazide), PPAH = 2-phenyl-N′-3-phenylallylideneacetohydrazide, FMPAH = N’-(furan-2-ylmethylene)-2-phenylaceto hydrazide and EPAH = N′-ethylidene-2-phenylacetohydrazide were synthesized by the condensation of 2-phenylacetohydrazide with the corresponding aldehyde. The synthesized compounds were characterized by FTIR, 1D, and 2D NMR spectroscopy. The structure of the BPAH and PPAH were analyzed by single crystal X-ray diffraction analysis and in both crystallized compounds, the molecules adopted trans geometry around the –CN- (imine) functional group. To explore the pharmacological significance of these compounds, the binding ability of these compounds with Bovine Serum Albumin (BSA) was investigated using fluorescence spectroscopy. BPAH and PPAH showed the highest binding ability while EPAH, HBPAH, and FMPAH had lower binding ability to BSA molecules. Thermodynamic parameters ΔG, ΔH°, and ΔS° demonstrated that interactions of BSA with compounds BPAH, EPAH, FMAH, and HBPAH were exothermic while for PPAH it was endothermic. The negative enthalpy and entropy of the compounds BPAH, EPAH, FMAH, and HBPAH indicated that van der Waals' forces and hydrogen bonding played a major role in stabilizing the BSA binding with the molecules. Hydrophobic interactions were predominant in the binding of PPAH with BSA tends to interact with two sets of BSA binding sites with an increase in temperature.

Investigating the binding interaction of quinoline yellow with bovine serum albumin and anti-amyloidogenic behavior of ferulic acid on QY-induced BSA fibrils

Protein aggregation induces profound changes in the structure along with the conformation of the protein, and is responsible for the pathogenesis of a number of neurodegenerative conditions such as Huntington’s, Creutzfeldt–Jacob, Type II diabetes mellitus, Alzheimer’s, etc. Numerous multi-spectroscopic approaches and in-silico experiments were utilized to investigate BSA’s biomolecular interaction and aggregation in the presence of quinoline yellow. The present research investigation evaluated the interaction of BSA with the food colorant (QY) at two different pH (7.4 and 2.0). The development of the BSA-QY complex was established with UV visible and fluorescence spectroscopy. The quenching of fluorescence upon the interaction of BSA with QY revealed the static nature of quenching mechanism. The Kb value obtained from our result is 4. 54 × 10−4 M−1. The results from the competitive site marker study infer that quinoline yellow is binding with the sub-domain IB of bovine serum albumin, specifically on site III. Three-dimensional fluorescence and synchronous fluorescence spectroscopy were applied for monitoring the alterations in the microenvironment of BSA upon the addition of quinoline yellow. The results from turbidity and RLS studies showed that higher concentrations of QY (80–400 µM) triggered bovine serum albumin (BSA) aggregation at pH 2.0. At pH 7.4, QY couldn’t manage to trigger bovine serum albumin aggregation, perhaps because of the repulsion between negatively charged dye (QY) and anionic bovine serum albumin. The results from far-UV CD, Congo Red, and scanning electron microscopy implicate that the QY-induced aggregates exhibit amyloid fibril-like structures. Molecular docking results revealed that hydrophobic interactions, hydrogen bonding, and Pi-Sulfur interactions contribute to QY-induced aggregation of BSA. Further, the amyloid inhibitory potential of ferulic acid (FA), a phenolic acid on QY-induced aggregation of BSA, has also been assessed. The QY-induced amyloid fibrils are FA-soluble, as confirmed by turbidity, RLS, and far-UV CD studies. Far-UV CD results showed that FA retains α helix and inhibits cross β sheet formation when the BSA samples were pre-incubated with increasing concentrations of FA (0–500 µM). Our findings conclude that QY dye successfully stimulates BSA aggregation, but ferulic acid inhibits QY-induced aggregation of BSA. Thus, FA can serve as a therapeutic agent and can help in the treatment of various amyloid-related conditions.

Biophysical insight into the binding mechanism of 1,3-benzodioxole-based lidocaine tagged ionic liquids with BSA: An in-silico, and spectroscopic studies

The interaction between bio-macromolecules and drugs has attracted significant interest for several decades due to their pharmacokinetics and pharmacological implications. Ionic liquids have a major importance in the development of effective drugs that can majorly target and bind to the proteins present in the body. A slight disturbance in the micro-environment of protein induced by a drug can alter the conformations of proteins to lead them to work differently. The interaction of ionic liquids with proteins present in blood such as HSA (Human Serum Albumin) and BSA (Bovine Serum Albumin) provides useful evidence for synthesizing API-based liquid drug and their delivery. In this study, the interaction of BSA with LPAc & LPOT ILs (LPAc: N-(benzo[d][1,3]dioxol-5-ylmethyl)-2-((2,6-dimethylphenyl)amino)-N,N-diethyl-2-oxoethan-1-aminium acetate and LPOT: N-(benzo[d][1,3]dioxol-5-ylmethyl)-2-((2,6-dimethylphenyl)amino)-N,N-diethyl-2-oxoethan-1-aminiumtrifluoromethane sulfonate) using spectroscopic methods like UV–visible, fluorescence, CD spectroscopy, computational studies (molecular docking, MD simulation studies, and ADMET studies). UV–vis spectra showed a slight rise in absorbance intensity with the addition of ionic liquid. A static quenching of BSA with blue shift was observed according to fluorescence spectra on the addition of ionic liquids (LPAc & LPOT) and conformational alterations of BSA were observed by analyzing CD spectra. LPAc and LPOT showed strong binding with BSA with molecular docking scores of −330.2 and −365.2 kcal/mol respectively. The molecular dynamic simulation and in-silico pharmacological and pharmacokinetics studies support the spectroscopic study and molecular docking results inferring that LPOT ionic liquid showed strong binding interactions with BSA. In-vitro studies against A549 cell lines showed that both LAPc and LPOT ionic liquids had antiproliferative properties and LPOT has better anticancer activity as inferred by IC50 value: 38.83 and may be further useful for drug design as cancer therapeutic.

Exploration of the intermolecular isoproturon–bovine serum albumin combination: Biophysical and computational prospects

Isoproturon (IPU), a selective systemic herbicide that is frequently applied to eradicate large-leaved weeds and annual grasses in agricultural fields. However, the accumulation of IPU residues during food production might negatively affect on human and animal health. To comprehend the impact of IPU on the mankind and environment, the interaction analysis of IPU with plasma protein is crucial. This work used a variety of techniques, including fluorescence, UV–vis absorption, computational docking and dynamics simulation to extensively examine the combination of IPU with bovine serum albumin (BSA) under typical physiological settings. IPU quenched the BSA fluorescence and form the IPU–BSA complex through a static process. A weak binding affinity was anticipated (binding constant = 4.68–2.48 × 103 M−1) for IPU–BSA interaction. Thermodynamic results revealed that the IPU–BSA binding reaction was a spontaneous process, predominantly governed by hydrogen bonds, van der Waals and hydrophobic forces, which was well supported by molecular docking analysis. Synchronous and three-dimensional fluorescence spectral results exhibited microenvironmental fluctuations near the protein’s Trp and Tyr residues with added IPU, but inclusion of IPU to BSA was observed to enhance the protein’s thermal constancy. Site marker displacement results demonstrated that IPU desirably binds to BSA at site II. An in silico findings also unveiled the primary binding arrangement of IPU was placed at site II of BSA and surrounded by hydrophobic and polar residues. Molecular dynamics simulation results suggested the IPU–BSA complex persisted compact and stable.

Synthesis of an Aryl-Semicarbazone-Based Cu(II) Complex for DNA and BSA Interaction and Anti-Cancer Activity against Human Cervix Uteri Carcinoma

The current study provides an in-depth analysis of the biological properties of a Cu(II) complex (C22H24Cu2N6O10) obtained from an aryl-semicarbazone ligand derived (L) from the condensation of 2,4-dihydroxy acetophenone and semicarbazide. The binding behavior of this complex with calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) protein was explored using a combination of experimental and theoretical approaches. The results suggest that the complex binds with CT-DNA via a partial intercalation, and hydrophobic interaction. However, the complex binds to BSA protein predominantly through hydrogen bonding or van der Waals interactions rather than hydrophobic interactions. The molecular docking methodology was carried out to substantiate the experimental finding. Furthermore, the in vitro cytotoxicity study was conducted on human cervix uteri carcinoma (SiHa cancerous cell) lines upon exposure to the complex, and the findings reveal a considerable decrease in cell viability, when compared to the control. Overall, this study provides a comprehensive understanding of the biological potential of the Cu(II) complex and its potential as an anti-cancer agent.

Probing the biomolecular interactions of oxidized Ti3C2Tx nanosheets: How surface chemistry influences serum protein binding

Ti3C2Tx has promising applications in the biomedical field due to its biocompatibility, hydrophilicity, and antibacterial activity. However, its effects on health are still being explored. This study analyzes the interaction of bovine serum albumin (BSA) with Ti3C2Tx at different levels of oxidation. Zeta potential measurements showed that the colloidal stability of Ti3C2Tx varied with the degree of oxidation, with unoxidized Ti3C2Tx (U-Ti3C2Tx) being the most stable, followed by fully oxidized Ti3C2Tx (F-Ti3C2Tx) and partially oxidized Ti3C2Tx (P-Ti3C2Tx). UV–Vis absorption and fluorescence spectroscopy confirmed that the formation of Ti3C2Tx-BSA complexes resulted in fluorescence quenching. In addition, synchronous fluorescence spectroscopy, Fourier transform infrared spectroscopy and circular dichroism showed that the interaction between F-Ti3C2Tx and BSA altered the secondary conformation of BSA, and that U-Ti3C2Tx had a weaker effect on the conformation of BSA. Molecular docking results emphasized that hydrogen bonding is the main driving force between Ti3C2Tx and BSA.

The effect of fatty acids, ionic strength, and electric fields on the microscopic dynamics of BSA aggregates

This paper presents the microscopic dynamics of the concentrated suspensions of bovine serum albumin (BSA) proteins and their aggregates by dynamic light scattering (DLS) experiments. The effects of fatty acids binding to BSA, as well as the ionic strength and weak electric field, are discussed for affecting the stability of BSA suspensions against calcium-induced aggregation. By variation of the ionic strength, in the absence of an external electric field, DLS experiments show that monomer–BSA interactions (in the essentially fatty acid-free case) are overall repulsive but that, nevertheless, aggregation occurs to some extent. Also, the diffusive properties of different types of BSA are explored under an applied low-AC electric field by means of in situ electric small-angle depolarized DLS experiments, which reveal a significant decrease of the translational BSA–monomer diffusion coefficient with increasing frequency, while the aggregates indicate orientational motion via rotation on applying an electric field. These observations are interpreted in terms of (localized) orientation interactions obtained as oscillations in the intermediate scattering correlation function, as well as the anomalous slower relaxations as resulting in effective (collective) dynamics between monomeric BSA and their protein aggregates.

Unveiling the Three-Step Model for the Interaction of Imidazolium-Based Ionic Liquids on Albumin.

The effect of the ionic liquids (ILs) 1-methyl-3-tetradecylimidazolium chloride ([C14MIM][Cl]), 1-dodecyl-3-methylimidazolium chloride ([C12MIM][Cl]), and 1-decyl-methylimidazolium chloride ([C10MIM][Cl]) on the structure of bovine serum albumin (BSA) was investigated by fluorescence spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, small-angle X-ray scattering (SAXS), and molecular dynamics (MD) simulations. Concerning the fluorescence measurements, we observed a blue shift and a fluorescence quenching as the IL concentration increased in the solution. Such behavior was observed for all three studied imidazolium-based ILs, being larger as the number of methylene groups in the alkyl chain increased. UV-vis absorbance measurements indicate that even at relatively small IL/protein ratios, like 1:1 or 1:2, ([C14MIM][Cl]) is able to change, at least partially, the sample turbidity. SAXS results agree with the spectroscopic techniques and suggest that the proteins underwent partial unfolding, evidenced by an increase in the radius of gyration (Rg) of the scattering particle. In the absence and presence of ([C14MIM][Cl]) = 3 mM BSA Rg increases from 29.1 to 45.1 Å, respectively. Together, these results indicate that the interaction of BSA with ILs is divided into three stages: the first stage is characterized by the protein in its native form. It takes place for protein/IL ≤ 1:2, and the interaction is predominantly due to the electrostatic forces provided by the negative charges on the surface of BSA and the cationic polar head of the ILs. In the second stage, higher IL concentrations induce the unfolding of the protein, most likely inducing the unfolding of domains I and III, in such a way that the protein's secondary structure is kept almost unaltered. In the last stage, IL micelles start to form, and therefore, the interaction with protein reaches a saturation point and free micelles may be formed. We believe that this work provides new information about the interaction of ILs with BSA.

Aggregation phenomena and physico-chemical properties of tetradecyltrimethylammonium bromide and protein (bovine serum albumin) mixture: Influence of electrolytes and temperature

It is important for biological, pharmaceutical, and cosmetic industries to understand how proteins and surfactants interact. Herein, the interaction of bovine serum albumin (BSA) with tetradecyltrimethylammonium bromide (TTAB) in different inorganic salts (KCl, K2SO4, K3PO4.H2O) has been explored through the conductivity measurement method at different temperatures (300.55 to 325.55 K) with a specific salt concentration and at a fixed temperature (310.55 K) using different salts concentrations. The extent of micelle ionization (α) and different thermodynamic parameters associated with BSA and TTAB mixtures in salt solutions were calculated. Evaluation of the magnitudes of ∆Hm0 and ∆Sm0 showed that the association was exothermic and primarily an enthalpy-operated process in all cases at lower contents of BSA, but the system became endothermic, and entropy driven in the presence of K3PO4.H2O at a relatively higher concentration of BSA. The enthalpy–entropy compensation variables were determined, which explained the types and nature of interactions between TTAB and BSA in salt media. Molecular docking analysis revealed that the main stabilizing factors in the BSA-TTAB complex are electrostatic and hydrophobic interactions. These findings aligned with the significant results obtained from the conductometry method regarding the nature and characteristics of binding forces observed between BSA and TTAB.

Synthesis, crystal structure, DNA and protein binding study of N-(4-pyridyl)-1,8-naphthalimide copper(II) complex

We have designed and synthesized 1,8-naphthalimide-based ligand N-(4-pyridyl)-1,8-naphthalimide (L) and its mixed ligand complex 1 [Cu(phen)2(L)](ClO4)2, where L = N-(4-pyridyl)-1,8-naphthalimide; phen=,10-phenanthroline. The synthesized copper complex has been structurally characterized with a single crystal X-ray determination study. The coordination geometry around the complex 1 is found to be distorted square pyramidal with N5 donor sites. The CT-DNA (calf thymus DNA) binding ability of the complex has been studied with various spectroscopic techniques such as UV–Vis and fluorescence spectroscopy. The viscosity measurements and circular dichroism (CD) spectral studies were also been studied to determine the CT-DNA binding mode. All the above studies indicate the groove binding mode of complex 1 to the CT-DNA. The interaction of bovine serum albumin (BSA) to the copper complex was investigated using fluorescence spectral studies and it is found to follow a dynamic quenching mechanism.

Quartz Crystal Microbalance Application and In Silico Studies to Characterize the Interaction of Bovine Serum Albumin with Plasma Polymerized Pyrrole Surfaces: Implications for the Development of Biomaterials.

Plasma polymerized pyrrole/iodine (PPPy/I) microparticles and bovine serum albumin (BSA) protein have shown interesting results in experimental models for the treatment of traumatic spinal cord injury. By studying the interaction between BSA and PPPy/I by a quartz crystal microbalance (QCM) and docking, we obtained important results to elucidate possible cellular interactions and promote the use of these polymers as biomaterials. These measurements were also used to characterize the adsorption process using an equilibrium constant. In addition, atomic force microscopy (AFM) was used to obtain images of the QCM surface sensors before and after BSA adsorption. Furthermore, we carried out molecular dynamics simulations and molecular docking to characterize the molecular recognition between BSA and the previously reported PPPy/I structure. For this study, we used two combinatorial models that have not been tested. Thus, we could determine the electrostatic (ΔGele) and nonelectrostatic (ΔGnonelec) components of the free binding energy (ΔGb). We demonstrated that BSA is adsorbed on PPPy/I with an adsorption constant of K = 24.35 μ-1 indicating high affinity. This observation combined with molecular docking and binding free energy calculations showed that the interaction between BSA and both combinatorial models of the PPPy structure is spontaneous.

Spectroscopic aspects on the interaction of nisin with serum albumin: thermodynamic and kinetic studies.

Nisin is a bacteriocin produced by Streptococcus and Lactococcus species and has antimicrobial activity against other bacteria. Nisin omits the need to use chemical preservatives in food due to its biological preserving properties. In the present in vitro study, we investigated nisin interaction with bovine serum albumin (BSA) using fluorescence spectroscopy and surface plasmon resonance (SPR) analysis to obtain information about the mechanisms of BSA complex formation with nisin. The BSA fluorescence intensity values gradually diminished with rising nisin concentration. The BSA fluorescence quenching analysis indicated that a combined quenching mechanism plays the main role. Finally, the Kb values were reduced with increasing temperature, which is demonstrative of nisin-BSA complex stability decrease at high temperatures. The negative values of ΔH° and ΔS° showed that hydrogen bonds and van der Waals forces are the foremost binding force between BSA and nisin. Meanwhile, the negative values of ΔG° demonstrated the exothermic and random nature of the reaction process. The results of the SPR verified the gained results through the fluorescence spectroscopy investigation, which denoted that the BSA affinity to nisin diminished upon increasing temperature. Overall, fluorescence spectroscopy and SPR results showed that the BSA interaction with nisin decreased with rising temperatures.

Mechanisms of the interaction of bovine serum albumin with quercetin

The peculiarities of the complexation of bovine serum albumin (BSA) and quercetin (Q) are shown in the article. The static mechanism of the formation of BSA-Q conjugates with the predominant effect of hydrogen bonds and hydrophobic interaction is established from fluorescence and absorption spectral data of aqueous solutions at different temperatures. The detailed analysis of an interaction of the molecules is performed in a molecular modeling procedure, including docking and molecular dynamics study. The computation results match the experimental outcome.

Structural characterization and stability of glycated bovine serum albumin-kaempferol nanocomplexes.

Kaempferol (Kae), a flavonoid is endowed with various functions. However, due to its poor water solubility and stability, its application in the food and pharmaceutical fields remains elusive. Emerging reports have emphasized the importance of bovine serum albumin (BSA), and glycosylated BSA (GBSA) prepared in the nature deep eutectic solvent system as drug delivery system carriers. In our study, ultraviolet and fluorescence spectra revealed the higher interactions of BSA and GBSA with Kae. Through analysis of Z-average diameter, zeta-potential, polydispersity index (PDI), encapsulation efficiency (EE), loading capacity (LC) of BSA-Kae nanocomplexes (NPs) and GBSA-Kae NPs, GBSA-Kae NPs showed a higher absolute value of zeta-potential and lower PDI, while its EE and LC were also higher. Structural characterization and stability analysis revealed that GBSA-Kae NPs had more stable properties. This study laid the theoretical foundation for improving the solubility and stability of Kae during its delivery and transport.

Mechanistic and kinetic aspects of Natamycin interaction with serum albumin using spectroscopic and molecular docking methods

Natamycin (NT) is a polyene natural antimycotic, which has an antimicrobial effect against yeasts and molds and is used as a preservative in the food industry. In the present study, we evaluated NT interaction with bovine serum albumin (BSA) through surface plasmon resonance (SPR) and several spectroscopic techniques, which are accompanied by a molecular docking study. According to the results, the intensity of BSA fluorescence decreased by adding different concentrations of NT. The fluorescence quenching results showed that NT reduces the intensity of BSA fluorescence by forming a complex with BSA through a hybrid quenching. Binding constant decreases from 18.73 to 2.13 (102 M−1) with increasing temperature, which indicates a decrease in complex formation owing to the interaction of NT with BSA. Negative values of ΔH° and ΔS° confirmed that van der Waals forces and hydrogen bonds are the basic forces in the interaction of NT with BSA. Moreover, increasing the equilibrium constants values with increasing temperature indicated that BSA binding to NT decreased. Finally, BSA interaction occurring with NT through Ser 109, Asp 111, Lys 114, Leu 115, Glu 424, and Arg 458 have been verified via molecular docking analysis. Attained results via SPR and fluorimetry showed that the binding constant between BSA and NT decreased when the temperature was raised.

In vitro interactions of two pesticides, propazine and quinoxyfen with bovine serum albumin: Spectrofluorometric and molecular docking investigations

Binding mechanisms of two selected pesticides, propazine (PRO) and quinoxyfen (QUI) with bovine serum albumin (BSA) was examined using fluorescence, absorption and molecular docking methods. Intrinsic fluorescence of BSA was quenched in the presence of both PRO and QUI. The quenching was ascertained to be conversely linked to temperature, which suggested the contribution of static quenching process in the PRO–BSA and QUI–BSA complex formations. This results were validated by the enhancement in absorption spectrum of BSA upon binding with PRO and QUI. Binding constant values (Kf = 9.55–0.60 × 10–3 M−1 for PRO–BSA system; Kf = 7.08–5.01 × 102 M−1 for QUI–BSA system) and number of binding site (n) values for the PRO–BSA and QUI–BSA systems at different temperatures affirmed a weak binding strength with a set of equivalent binding sites on BSA. Thermodynamic data obtained for both the PRO–BSA and QUI–BSA interactions predicted that the association process was spontaneous and non-covalent contacts such as hydrophobic interactions, van der Waals forces and hydrogen bonds participated in the binding reactions. This result was further supported by the molecular docking assessments. Three-dimensional spectral results revealed the microenvironmental alterations near tryptophan (Trp) and tyrosine (Tyr) residues in BSA by the addition of PRO and QUI. The docking analysis demonstrated the binding pattern for the PRO–BSA and QUI–BSA systems and disclosed the preferred binding site of both PRO and QUI as site I (subdomain IIA) of BSA.