Secondary Structure Of BSA Research Articles

A novel approach to chiral separation: thermo-sensitive hydrogel membranes.

The application of membrane technology for separating chiral compounds is hindered due to the restricted availability of chiral recognition sites on the membrane surface. In this study, we propose a novel approach for chiral separation through a selector (bovine serum albumin, BSA) mediated thermo-sensitive membrane system. A thermo-sensitive hydrogel-coated membrane (termed PDTAN) was developed by anchoring poly(N-isopropylacrylamide) (PNIPAm) onto a polyethersulfone (PES) membrane through an adhesive and hydrophilic dopamine hydrochloride (PDA)/tannic acid (TA)/chitosan (Chi) intermediate layer. The results demonstrate outstanding chiral separation efficiency, achieving αL/D = 3.30 for D-phenylalanine (D-Phe) rejection at 40 °C on a BSA-mediated PDTAN membrane system, with significant stability and minimal fouling, surpassing previous findings. Moreover, the PDTAN membrane altered the selective properties of recognition sites in BSA, transitioning from rejecting L-Phe to rejecting D-Phe. Analysis using fourth-order derivative UV-vis, circular dichroism (CD), and in situ Fourier transform infrared spectroscopy (FTIR) techniques revealed a transition in the secondary structure of BSA from α-helix to β-sheet as the temperature increased. This transition, facilitated by hydrogen bonding between BSA and PNIPAm, enabled selective recognition of D-Phe, demonstrating a distinct shift in chiral recognition properties. Importantly, with D-Phe adsorbed onto β-sheet structures of BSA, hydrogen-bond interactions between BSA and the PDTAN membrane were significantly reduced, thereby minimizing membrane fouling and achieving the durability of membrane-based chiral separation.

Kinetic and thermodynamic aspects on the interaction of serum albumin with sodium hydrosulfite: Spectroscopic and molecular docking methods

Sodium hydrosulfite is a sulfur-containing food additive that is used as a decolorizing agent in the sugar industry to purify syrup and remove natural color compounds obtained from sugar beet, sugar cane, and color compounds created during production. Recent studies show gastrointestinal, aspiration, skin and eye complications from excessive use of sulfur-containing compounds. According to recent studies and the importance of investigating the interaction of food additives with biological molecules, we also investigated the binding properties of sodium hydrosulfite to blood serum albumin through UV–Vis spectroscopy, fluorescence spectroscopy, competitive binding experiments, Fourier transform infrared spectrometry (FT-IR), surface plasmon resonance (SPR), and molecular simulation analysis. According to the results, Sodium hydrosulfite decreased the fluorescence intensity of BSA through both static and dynamic quenching mechanisms after forming a complex with BSA. The results of synchronous fluorescence and FT-IR demonstrated that the microenvironment and the secondary structure of BSA were changed in the presence of sodium hydrosulfite. The negative values of ΔH° and ΔS° indicated that van der Waals force or hydrogen bonding is the main factor of binding between sodium hydrosulfite and BSA. The result of UV–Vis spectroscopy confirmed the binding of sodium hydrosulfite to BSA. Binding constant decreases from 13.06 to 0.24 (103 M−1) with increasing temperature, which indicates a decrease in complex formation owing to the interaction of sodium hydrosulfite with BSA. Molecular docking experiments confirm the binding tendency of sodium hydrosulfite to a cavity between domains II and III (Site I and Site II) through residues Cys460, Cys476, Asn457, Arg483, Lys204, and Ala200 with a binding energy of −12.86 kJ mol−1.

Investigation of the separate and simultaneous bindings of warfarin and fenofibrate to bovine serum albumin

Lipid-lowering drugs are often taken with anticoagulant drugs in hyperlipidemia patients. Fenofibrate (FNBT) and warfarin (WAR) are common clinical lipid-lowering drugs and anticoagulant drugs, respectively. A study of binding affinity, binding force, binding distance, and binding sites was performed to determine the interaction mechanism between drugs and carrier proteins (bovine serum albumin, BSA), as well as their effects on BSA conformation. Both FNBT and WAR can form complexes with BSA by van der Waals force and hydrogen bonds. WAR had a stronger fluorescence quenching effect on BSA, a stronger binding affinity, and greater effects on BSA conformation than FNBT. According to fluorescence spectroscopy and cyclic voltammetry, co-administration of drugs decreased one drug's binding constant to BSA and increased its binding distance. This suggested that each drug's binding to BSA was disturbed by each other, as well as each drug's binding ability to BSA was altered by the other. It was demonstrated that co-administration of drugs had greater effects on the secondary structure of BSA and microenvironment polarity surrounding amino acid residues, using multiple spectroscopy techniques, such as ultraviolet spectroscopy, Fourier transform infrared spectroscopy, and synchronous fluorescence spectroscopy.

Mixed ligand octahedral Zn(II) complex of N^N^O donor tridentate Schiff base ligand and N^N donor bidentate bipyridine ligand: Synthesis, characterization, biological activity and cytotoxicity

AbstractTridentate NNO donor Schiff base ligand and its mixed ligand zinc(II) complex were synthesized stoichiometrically and characterized by electronic, infrared, mass spectral techniques and elemental analysis. To understand the DNA binding ability, the complex was investigated by various analytical and spectroscopic techniques in presence of calf thymus DNA (CT‐DNA). The binding studies showed that the zinc complex interacts with DNA by groove binding mode with intrinsic binding strength of 2.11 × 105 M−1 and with bovine serum albumin the complex showed dynamic quenching attributed for changes in the secondary structure of BSA with efficient interaction. The MCF‐7 cell line studies of the zinc(II) complex with 90.8 μM IC50 value revealed that the complex is effective for the breast cancer cell line and has a potential as anticancer drug. Furthermore, the tridentate ligand and its mixed ligand zinc complex were screened for antibacterial and antifungal activities, which showed better antimicrobial activity for complex.

Exploration of the binding between cuminol and bovine serum albumin through spectroscopic, molecular docking and molecular dynamics methods

Cuminol (4-Isopropylbenzyl alcohol), found in the essential oils of several plant sources, is an important constituent of several cosmetics formulations. The interaction of cuminol with model plasma protein bovine serum albumin was studied in this paper. The experimental studies were mainly carried out using fluorescence spectrophotometry aided with UV visible and CD spectroscopies. Intrinsic fluorescence measurements showed that there was a weak binding between cuminol and BSA. The mechanism of binding involved static quenching with around 1:1 binding. The binding was chiefly supported by hydrophobic forces although a little contribution of hydrogen bonding was also found in the interaction and the values of enthalpy change were negative with positive entropy change. The secondary structure of BSA didn’t change significantly in presence of low concentrations of cuminol, however, partial unfolding of the former taken place when the concentration of the latter increased. Molecular docking analyses showed cuminol binds at the intersection of subdomains IIA and IIIA, i.e. its binding site is in between Sudlow sites I and II. Molecular dynamics simulations results have shown that BSA forms a stable complex with cuminol and the structure of the former didn’t change much in presence of later. Communicated by Ramaswamy H. Sarma

Features of the Secondary Structure of BSA – Containing Protein Complexes, Isolated from Milk of High Temperature Processing

Present paper describes features of the component composition in the secondary structure of BSA–containing protein complexes isolated from ultra-pasteurized (UHT), sterilized (SHT) and powdered (DRY) milk. We have found β – sheets to present in all complexes investigated. However, the smallest number of such components have been revealed in samples derived from sterilized milk with less β – sheets in 1621–1626 cm–1 region. The composition study of the complexes originated from UHT milk has shown random coils to be the rarest in them. When considering the structure of the complexes isolated from powdered milk, the α – 310 – heliсes were more characteristic for such samples, then the α – helix. Moreover, during spray–drying, the number of random structures increase with a simultaneous decrease in the number of β – sheets, whereas in UHT – and SHT – processing the number of random structures is inversely proportional to the number of α – helices.

Evaluation of the antiglycating potential of thymoquinone and its interaction with BSA

Thymoquinone (TQ) is a bioactive component of medicinal plant, Nigella sativa. It has been identified as promising anti-inflammatory and anti-analgesic properties. In the present study, the TQ has been investigated for physiological interaction as well as binding properties with serum albumin and their thermodynamic parameters at different temperatures. Glycation process was checked with the measurement of fructosamine content, carbonyl content and total advanced glycated end products. The aggregation of amyloid β-structure was measured with Thioflavin-T and the secondary structure of BSA was observed by circular dichroism (CD) in glycated and thermal treated samples. The results indicate that the TQ showed binding interaction (both static and dynamic) with BSA (K b= 18.31 × 107 M −1 at 293 K) and suppression of glycated products. The glycation-induced and thermal aggregation were prevented and the secondary structure of BSA was maintained. Therefore, these findings suggest that TQ may be used for a therapeutic drug for antiglycation as well as anti-aggregation. Communicated by Ramaswamy H. Sarma

Glycyrrhizic Acid Scavenges Reactive Carbonyl Species and Attenuates Glycation-Induced Multiple Protein Modification: An In Vitro and In Silico Study.

The current study is aimed at studying the inhibitory effect of glycyrrhizic acid (GA) on D-ribose-mediated protein glycation via various physicochemical analyses and in silico approaches. Being a potent free radical scavenger and a triterpenoid saponin, GA plays a vital role in diminishing the oxidative stress and thus could be an effective inhibitor of the nonenzymatic glycation process. Our data showed that varying concentrations of GA inhibited the in vitro BSA-AGEs via inhibiting the formation of fructosamines, fluorescent AGEs, scavenging protein carbonyl and hydroxymethyl furfural (HMF) content, and protection against D-ribose-induced modification of BSA as evident by increased free Arg and Lys residues in GA-treated Gly-BSA samples. Moreover, GA also attenuated D-ribose-induced alterations in the secondary structure of BSA by protecting the α-helix and β-sheet conformers and amide-I band delocalization. In addition, GA attenuated the modification in β-cross amyloid structures of BSA and in silico molecular interaction study too showed strong binding of GA with higher number of Lys and Arg residues of BSA and binding energy (ΔG) of -8.8 Kcal/mol, when compared either to reference standard aminoguanidine (AG)-BSA complex (ΔG: -4.3 Kcal/mol) or D-ribose-BSA complex (ΔG: -5.2 Kcal/mol). Therefore, GA could be a new and favorable inhibitor of the nonenzymatic glycation process that ameliorates AGEs-related complications via attenuating the AGE formation and glycation-induced multiple protein modifications with a reduced risk of adverse effects on protein structure and functionality; hence, it could be investigated at further preclinical settings for the treatment and management of diabetes and age-associated complications.

Spectral and molecular modelling studies of sulfadoxine interaction with bovine serum albumin

The present study is focused on the binding interaction of sulfadoxine with bovine serum albumin under simulated physiological conditions using spectrofluorimetry. Various spectroscopic and other methods like UV–vis, Raman, FTIR, CD, lifetime measurement, cyclic voltammetry were also employed during the course of study. It was noticeable that sulfadoxine did quench the intrinsic fluorescence of BSA via static quenching process. UV–vis study enabled the calculation of association constant, Kass for the interaction of BSA and sulfadoxine. The change in the secondary structure of BSA and binding mechanism was investigated with the spectral and docking studies. The meticulous investigation of competitive binding sites using various probes was studied and it was clear that drug binding was non-specific. Effect of some co-existent drugs and metal ions were examined which may help in the controlled release of drugs.

Multi-spectroscopic approaches combined with theoretical calculation to explore the intermolecular interaction of telmisartan with bovine serum albumin

Intermolecular interaction of telmisartan (TMST), an angiotensin II receptor antagonist with bovine serum albumin was explored in vitro by the means of multi-spectral approaches such as UV absorption, stead-state fluorescence, synchronous fluorescence, 3-D fluorescence, and infrared spectroscopies in combination with theoretical calculation. The UV absorption and steady-state fluorescence studies manifested that BSA interacted with TMST leading to the fluorescence of both BSA and TMST were quenched through a static quenching manner. It can be found that a TMST-BSA complex with the stoichiometric ratio of 1:1 was formed and the binding constant (Kb) was 7.26 × 103 M−1 at 298 K(close to 104 M−1), suggesting TMST was a moderate affinity on BSA, and its value diminished with the rising temperature, predicating the binding interaction of TMST with BSA was an exothermic reaction. The results from the competitive exploration and molecular modeling have confirmed that TMST primarily inserted into the hydrophobic cavity between sub-domain IIA and IIB of BSA. The calculated ΔH and ΔS values on the base of van't Hoff equation were −40.02 kJ·mol−1 and −60.46 J·mol−1·K−1, meaning that hydrogen bonds and van der Waals force played dominating roles in the TMST–BSA system. The results of FT-IR spectra suggested that the alteration in the secondary structure of BSA like the decline in the contents of α-helix and β-sheets and the increase in the random coil. Meantime, the obvious variety in the configuration of TMST occurred after binding to fit the configuration of binding pocket.

Investigation of binding interactions between BSA and [EPMpyr][Sal] through spectroscopy studies, thermophysical and thermodynamic properties

The intensity of research, probing the interactions between proteins and ionic liquid (IL), has been increasing and parallels the fast-growing applications of ILs in biotechnology. The specific aspects which have attracted the involvement of researchers are stabilization, separation, biochemical and enzymatic reactions of proteins. In this work the synthesis of IL, epoxypropyl and N-methyl substituted 2‑oxopyrrolidinium cation with salicylate anion, [EPMpyr][Sal], and its interaction with aqueous BSA{BSA(aq)-[EPMpyr][Sal]}. Measurements of thermophysical properties (density (ρ), and speed of sound (u)) showed that both moderately strong and weak interactions occur on treatment of BSA with that chosen IL. H-bond formation, dipole-dipole interactions and ionic interactions occurring in this system were investigated via thermophysical and thermodynamic properties as well as spectroscopic data. Thermodynamic data (excess molar volume (VmE), isentropic compressibility (ks), deviation in isentropic compressibility (∆ks) and intermolecular free length (Lf)) showed that there were stronger interaction between IL and BSA at higher temperature. The data from all the studies were correlated with Redlich Kister polynomial equation. The blue shift observed in the fluorescent spectra was interpreted to indicate that thetryptophan (Trp) residue of BSA moves to a more hydrophobic environment. It was also observed that the addition of more IL to BSA resulted in denaturation of BSA due to high hydrophobic nature of IL. Circular dichroism studies show that there were significant changes in the fine structure of BSA on interaction with IL. From the FTIR spectra the position of H-bond in the secondary structure of BSA was deduced.

Spectroscopic exploration of interaction between PEG-functionalized Ag2S nanoparticles with bovine serum albumin

The introduction of nanoparticles into biological fluids often leads to the formation of biocorona over the surface of nanoparticles. For the effective use of nanoparticles in biological applications it is very essential to understand their interactions with proteins. Herein, we investigated the interactions of Poly ethylene glycol capped Ag2S nanoparticles with Bovine Serum Albumin by spectroscopic techniques. By the addition of Ag2S nanoparticles, a ground state complex is formed. The CD spectroscopy reveals that the secondary structure of BSA is altered by complexation with PEG-Ag2S nanoparticles, while the overall tertiary structure remains closer to that of native BSA.

Dynamic analysis of the interactions between Si/SiO2 quantum dots and biomolecules for improving applications based on nano-bio interfaces

Due to their outstanding properties, quantum dots (QDs) received a growing interest in the biomedical field, but it is of major importance to investigate and to understand their interaction with the biomolecules. We examined the stability of silicon QDs and the time evolution of QDs – protein corona formation in various biological media (bovine serum albumin, cell culture medium without or supplemented with 10% fetal bovine serum-FBS). Changes in the secondary structure of BSA were also investigated over time. Hydrodynamic size and zeta potential measurements showed an evolution in time indicating the nanoparticle-protein interaction. The protein corona formation was also dependent on time, albumin adsorption reaching the peak level after 1 hour. The silicon QDs adsorbed an important amount of FBS proteins from the first 5 minutes of incubation that was maintained for the next 8 hours, and diminished afterwards. Under protein-free conditions the QDs induced cell membrane damage in a time-dependent manner, however the presence of serum proteins attenuated their hemolytic activity and maintained the integrity of phosphatidylcholine layer. This study provides useful insights regarding the dynamics of BSA adsorption and interaction of silicon QDs with proteins and lipids, in order to understand the role of QDs biocorona.

Investigating the structural integrity of Bovine serum albumin in presence of newly synthesized metallosurfactants

Bovine Serum Albumin is major transport protein and is often used as a drug carrier in body organs. Knowledge of its binding with metallosurfactant can significantly influence the biodistribution of metallodrugs. Current work demonstrated a facile method to prepare four different double chained metallosurfactants containing Fe, Co, Ni and Cu as part of their counter ion. The as-synthesized metallosurfactants were characterized using FTIR, AAS, TGA and XRD in solid form. The aggregation of these metallosurfactants in aqueous medium was investigated through conductivity, surface tension and SAXS. Further, we have investigated their binding with BSA through different analytical methods The effect of concentration of metallosurfactants on the primary and secondary structure of BSA was further examined by SDS-PAGE and Circular dichroism, respetively. It is found that at premicellar concentration, the primary structure of BSA was not affected but the secondary structure i.e. α-helical structure of BSA was altered as shown by circular dichroism. Interestingly, post micellar concentration of metallosurfactants shows the pronounced effect on the primary and secondary structure of BSA. SAXS study also supports the fact of unfolding of protein and its wrapping around the micelles. Zeta potential describes the electrical charge and stability of the protein in the presence of different concentration of metallosurfactant. Along with, it was found that presence of protein delays the aggregation behavior of metallosurfactant, as a sign of binding of BSA with metallosurfactant.

Effects of Excipient Interactions on the State of the Freeze-Concentrate and Protein Stability.

The physical state of excipients in freeze-dried formulations directly affects the stability of the active pharmaceutical ingredient (API). Crystallization of trehalose and mannitol in frozen solutions has been shown to be a function of composition. However, to date a detailed study of the effect of concentrations of the API and other excipients on the crystallinity of mannitol and trehalose in frozen solutions has not been reported. The crystallinity of mannitol and trehalose in frozen solutions was characterized by Differential Scanning Calorimetry, X-ray diffractometry, and FTIR spectroscopy. The secondary structure of BSA was probed by FTIR, and Circular Dichroism spectroscopy in frozen and thawed solutions, respectively. Trehalose crystallization was accompanied by unfolding of BSA. BSA delayed and reduced the extent of mannitol and trehalose crystallization. Similar effects were observed upon adding D2O (≥5% w/w) and low concentrations of polysorbate 20 (≤0.2% w/w) with retention of BSA in its native conformation. At high BSA to trehalose mass ratio, the protein could stabilize itself in the frozen state, but unfolded upon thawing. The API and other excipients, in a concentration-dependent manner, influenced the physical state of the freeze concentrate as well as the stability of the API.

Synthesis, electronic structure and molecular docking of new organometallic palladium (II) complexes with intercalator ligands: The influence of bridged ligands on enhanced DNA/serum protein binding and in vitro antitumoral activity

Novel organometallic palladium(II) complexes [Pd2{(C,N)C12H8NH2)}2(μ-dppf)Cl2] (2) [Pd2{(C,N)C12H8NH2)}2(μ-dpp)Cl2] (3) [1,1-bis(diphenylphosphine)-ferrocene (dppf), 1,3-Bis(4-pyridyl)propane (bpp)] have been synthesized, fully characterized by elemental analysis, multi-nuclear (1H,31P{1H},13C{1H}) NMR and IR spectroscopic techniques and their biological activities such as anti-tumoral activity and DNA-protein interactions have been investigated. The crystal structure of (2), established by X-ray diffraction, shows that the dppf ligand is bound to the two palladium atoms in bridged form. The interaction of the complexes with calf thymus DNA (CT-DNA) has been explored by UV–Vis spectroscopy, emission titration and thermal denaturation (Tm) methods, which have revealed that these complexes interact with DNA through intercalation mode. Competitive studies with methylene blue (MB) have shown the ability of the complexes to displace the DNAbound MB, suggesting a competition with MB. Furthermore, the microenvironment and the secondary structure of BSA are changed in the presence of the complexes. Competitive binding using Warfarin, Digoxin and site markers, which have definite binding sites, demonstrated that the complexes bind to site I on BSA. Notably, the complexes exhibit significant in vitro selective cytotoxicity against two human cancer cell lines (JURKAT and SKOV3) with IC50 values varying from 2.3 to 6.7 μM. This indicates that they are more active than cisplatin and showing low cytotoxic activity on normal cells. Finally, molecular modelling studies have been conducted to determine the binding site of the DNA and BSA with the complexes.

Spectroscopic profile of surfactant functionalized CdSe quantum dots and their interaction with globular plasma protein BSA

Herein, we report on the differential structural and optical properties of CdSe quantum dots (QDs) (size group 2.5 and 3.5nm) which were synthesized with four different surfactant coatings using hot-injection method. The surface functionalization led to change in the morphology of agglomerated QDs that generated structures such as tetrapods, clusters and networks. Steady state fluorescence showed capping dependent changes in the quantum yield. In particular, QDs formed with TX-100 (Triton X-100) coating, revealed highest quantum yield, compared to QDs synthesized with oleic acid (OA), and three other surfactants (CTAB, DTAB and SDS). These functionalized QDs were interacted with model plasma protein BSA which revealed the protein-QD binding order: BSA-QD1 (2.5nm)<BSA-QD2 (3.5nm). Maximum binding occurred with DTAB coated QDs. Such interaction led to considerable loss in the secondary structure of BSA. The surface ligands could control the passivation of surface states and non-radiative energy loss pathways.

Inhibition Mechanism of Calcium Oxalate Crystal Growth by Cooperation Influence of Colloidal Selenium Nanoparticles and Bovine Serum Albumin

This study investigated the effect of colloidal selenium nanoparticles modified with bovine serum albumin (nanoSe0–BSA) on the crystal phase and morphology of CaC2O4 and explained the cooperative inhibition mechanism of nanoSe0 and BSA on the crystallization of CaC2O4. The results were compared with those for nanoSe0 and BSA individually. NanoSe0 could induce the formation of oval or spherical calcium oxalate monohydrate (COM) crystals at high concentrations. BSA could induce the formation of hexagonal plate-shaped COM crystals at low concentrations and the formation of thin diamond-shaped COM crystals and mixed hydrates with cracks at high concentrations. NanoSe0–BSA showed additive effects on CaC2O4 crystal growth. NanoSe0–BSA could induce the formation of mixed hydrates with more surface cracks and obvious voids at relatively low BSA concentrations. These mixed hydrates were considered to be calcium oxalate trihydrate (COT) or calcium oxalate dihydrate (COD) crystals containing BSA or nanoSe0–BSA. These results were a consequence of the interaction of nanoSe0 with BSA. UV–vis, circular dichroism, and FT-IR spectra indicated that the binding of nanoSe0 to BSA induces a change in the secondary structure of BSA and forms the complex. The nanoSe0–BSA binding constant (2.257 × 104 L mol–1) and number of binding sites (1.13) were calculated from the data of fluorescence spectra.

A mononuclear zinc(II) complex with piroxicam: Crystal structure, DNA- and BSA-binding studies; in vitro cell cytotoxicity and molecular modeling of oxicam complexes

A new mononuclear Zn(II) complex, trans-[Zn(Pir)2(DMSO)2], where Pir− is 4-hydroxy-2-methyl-N-2-pyridyl-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide (piroxicam), has been synthesized and characterized. The crystal structure of the complex was obtained by the single crystal X-ray diffraction technique. The interaction of the complex with DNA and BSA was investigated. The complex interacts with FS-DNA by two binding modes, viz., electrostatic and groove binding (major and minor). The microenvironment and the secondary structure of BSA are changed in the presence of the complex. The anticancer effects of the seven complexes of oxicam family were also determined on the human K562 cell lines and the results showed reasonable cytotoxicities. The interactions of the oxicam complexes with BSA and DNA were modeled by molecular docking and molecular dynamic simulation methods.

A rare dihydroxo copper(ii) complex with ciprofloxacin; a combined experimental and ONIOM computational study of the interaction of the complex with DNA and BSA

A rare mononuclear Cu(II) complex, trans-[Cu(cip)2(OH)2]·2CH3OH·6H2O, where cip+/− is a zwitterionic form (+H2N–⋯–COO−) of ciprofloxacin, has been synthesized and characterized by spectroscopic methods and X-ray crystallography. In vitro studies (UV-Vis spectroscopy, emission titration, voltammetric techniques, and gel electrophoresis) show that the complex interacts with calf-thymus DNA (CT-DNA) via an intercalative binding mode. The microenvironment and the secondary structure of BSA are changed in the presence of the complex. Also, our Own N-layered Integrated molecular Orbital and molecular Mechanics (ONIOM) method, based on the hybridization of QM/MM methodology, was carried out to investigate the interaction of the complex with DNA and BSA. The calculated electronic interaction energy of the complex with DNA in the gas phase and water is −64.358 and −56.685 kcal mol−1, respectively. The calculated interaction of the complex with BSA is −54.231 kcal mol−1. The theoretical data confirm the experimental results with respect to the mechanism of binding and binding constants. Finally, the calculations indicate that the QM/MM is a more precise method than the docking method for determination of the electronic interaction energies because of two reasons: (I) it considers the complex quantum mechanically in calculations, and (II) it accounts for the polarization of the wave function of the complex by the charge distribution of the molecular mechanical part (DNA and BSA).