Influence of Rutin, Sinapic Acid, and Naringenin on Binding of Tyrosine Kinase Inhibitor Erlotinib to Bovine Serum Albumin Using Analytical Techniques Along with Computational Approach

A 3D copper (II) coordination polymer based on sulfanilic acid ligand (CP 1) for efficient biomolecular interaction with bovine serum albumin: spectroscopic, molecular modelling and DFT analysis

Several biochemical reactions occur during the interaction of metal complexes and proteins due to conformational modifications in the structure of the protein, which provide fundamental knowledge of the effect, mechanism, and transport of many drugs throughout the body. Here, we report the synthesis, identification, and impact of the 3-dimensional Copper(II)sulfanilic acid coordination polymer (CP 1) on interactions with bovine serum albumin (BSA). The CP 1 was synthesized via a simple hot stirring method, and the single crystal XRD confirms the effective bonding interactions between metal and organic ligand, forming a crystalline polymeric chain and the topological study shows the sql type of underlying net topology. Powder XRD, Fourier transform infrared spectroscopy, and thermogravimetric analysis were also performed. Moreover, DFT/B3LYP calculations provide chemical precision for the resulting complex. Further, the changes that occur in the secondary structure of protein when CP 1 binds with BSA as well as its binding capacity were investigated via circular dichroism analysis and spectroscopic methods such as UV-absorption spectroscopy and fluorescence spectroscopy, respectively. The CP 1/BSA complex melting point was also measured, and its temperature-dependent heat denaturation was studied along with molecular docking.Communicated by Ramaswamy H. Sarma.

Investigating the Serum Albumin Binding Behavior of Naphthalimide Based Fluorophore Conjugates: Spectroscopic and Molecular Docking Approach

In the present study, naphthalimide-pyrazole-benzothiazole based fluorescent analogs were synthesized by substituting different primary and secondary amines on the naphthalimide nucleus and were evaluated for their sensitivity and selectivity towards serum albumin. Among various synthesized analogues compound 25 showed the most significant change with serum albumin and was further studied for selective detection and mode of interaction with serum albumin. Here, we compared the binding interaction of fluorescent probe 25 for variation/detection of two 76 % structurally resembling proteins HSA and BSA, by spectroscopic experiments. The compound shows more selectivity for HSA and BSA with a higher binding constant and evident visible change in the emission spectra of two serum albumins among different bioanalytes. The mode of interaction of 25 with human serum albumin and bovine serum albumin was investigated by FT-IR, circular dichroism, and DLS techniques to find out the change in the microenvironment and variation in the structure of serum albumin proteins. Higher binding affinity and specific selectivity of 25 with a limit of detection of 0.69 μM and 1.4 μM towards HSA and BSA compared to other bioanalytes make it a significant fluorescent probe for quantitatively detecting serum albumins at the very early stage of many fatal diseases.

In-Vitro Study of the Binding of Atorvastatin with Adenine using Multi-Spectroscopic Approaches

Atorvastatin-an oral lipid regulating drug is a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase), which is the rate determining enzyme for cholesterol synthesis. Adenine is a purine nucleobase that is found in deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) to generate genetic information. The binding mechanism of atorvastatin and adenine was studied for the first time utilizing various techniques, including UV-visible spectrophotometry, spectrofluorimetry, synchronous fluorescence spectroscopy (SF), Fourier transform infrared (FTIR), fluorescence resonance energy transfer (FRET), and metal ion complexation. The fluorescence spectra of the complex indicated that atorvastatin is bound to adenine via hydrophobic interaction through a spontaneous binding process, and the fluorescence quenching mechanism was found to be static quenching with a binding constant of 1.4893 × 104 Lmol-1 at 298 K. Various temperature settings were used to investigate thermodynamic characteristics, such as binding forces, binding constants, and the number of binding sites. The interaction parameters, including the standard enthalpy change (ΔHο) and standard entropy change (ΔSο) were calculated using Van't Hoff's equation to be 42.82 kJmol-1 and 208.9 Jmol-1K-1, respectively. The findings demonstrated that the adenine- atorvastatin binding was endothermic. Furthermore, the results of the experiments revealed that some metal ions (K+, Ca+2, Co+2, Cu+2, and Al+3) facilitate the binding interaction between atorvastatin and adenine. Slight changes are observed in the FTIR spectra of adenine, indicating the binding interaction between adenine and atorvastatin.

Insights into the binding of buspirone to human serum albumin using multi-spectroscopic and molecular docking techniques

Buspirone is an anxiolytic drug that plays a significant role in managing anxiety disorders and alleviating their symptoms as well. Several techniques were utilized to study the interaction between buspirone and human serum albumin under physiological conditions, including UV-vis absorption spectroscopy, fluorescence emission spectroscopy, circular dichroism, Fourier transform infrared spectroscopy (FT-IR), equilibrium dialysis, and molecular docking. The results of this study demonstrated that buspirone quenched the intrinsic fluorescence of human serum albumin through a mixed mechanism. Moreover, the binding constants (Kb), the quenching constants (Ksv), and thermodynamic parameters were calculated at various temperatures. The binding process of buspirone to human serum albumin showed a cooperative binding pattern, confirmed by the Scatchard diagram and Hill coefficient. Molecular docking results showed that buspirone interacted with the IIA, IIIA, and IIB subdomains of human serum albumin and slightly changed its conformation. It was also found that hydrophobic forces played a major role in this interaction. This study consequently proves that BSH as a drug can be transported by blood albumin. Additionally, due to its ratiometric response in absorbance upon binding to a biological target, HSA can be used as a molecular probe to follow biomolecular interactions.

Comprehending the intermolecular interaction of dacomitinib with bovine serum albumin: experimental and theoretical approaches

Dacomitinib (DAC), as a member of tyrosine kinase inhibitors is primarily used to treat non-small cell lung cancer. The intermolecular interaction between DAC and bovine serum albumin (BSA) was comprehended with the help of experiments and theoretical simulations. The outcomes indicated that DAC quenched the endogenous fluorescence of BSA through static quenching mode. In the binding process, DAC was preferentially inserted into the hydrophobic cavity of BSA subdomain IA (site III), and a fluorescence-free DAC-BSA complex with molar ratio of 1:1 was generated. The outcomes confirmed that DAC had a stronger affinity on BSA and the non-radiative energy transfer occurred in the combination process of two. And, it can be inferred from the outcomes of thermodynamic parameters and competition experiments with 8-aniline-1-naphthalenesulfonic acid (ANS) and D-(+)- sucrose that hydrogen bonds (H-bonds), van der Waals forces (vdW) and hydrophobic forces had a significant impact in inserting DAC into the hydrophobic cavity of BSA. The outcomes from multi-spectroscopic measurements that DAC could affect the secondary structure of BSA, that was, α-helix content decreased slightly from 51.0% to 49.7%. Moreover, the combination of DAC and BSA led to a reduction in the hydrophobicity of the microenvironment around tyrosine (Tyr) residues in BSA while had little influence on the microenvironment of around tryptophan (Trp) residues. The outcomes from molecular docking and molecular dynamics (MD) simulation further demonstrated the insertion of DAC into site III of BSA and hydrogen energy and van der Waals energy were the dominant energy of DAC-BSA stability. In addition, the influence of metal ions (Fe3+, Cu2+, Co2+, etc.) on the affinity of the system was explored.Communicated by Ramaswamy H. Sarma.

Spectroscopy and molecular simulation on the interaction of Nano-Kaempferol prepared by oil-in-water with two carrier proteins: An investigation of protein-protein interaction

In this work, the interaction of human serum albumin (HSA) and human holo-transferrin (HTF) with the prepared Nano-Kaempferol (Nano-KMP) through oil-in-water procedure was investigated in the form of binary and ternary systems by the utilization of different spectroscopy techniques along with molecular simulation and cancer cell experiments. According to fluorescence spectroscopy outcomes, Nano-KMP is capable of quenching both proteins as binary systems by a static mechanism, while in the form of (HSA-HTF) Nano-KMP as the ternary system, an unlinear Stern-Volmer plot was elucidated with the occurrence of both dynamic and static fluorescence quenching mechanisms in the binding interaction. In addition, the two acquired Ksv values in the ternary system signified the existence of two sets of binding sites with two different interaction behaviors. The binding constant values of HSA-Nano KMP, HTF-Nano-KMP, and (HSA-HTF) Nano-KMP complexes formation were (2.54 ± 0.03) × 104, (2.15 ± 0.02) × 104 and (1.43 ± 0.04) × 104M-1at the first set of binding sites and (4.68 ± 0.05) × 104 M-1 at the second set of binding sites, respectively. The data of thermodynamic parameters confirmed the major roles of hydrogen binding and van der Waals forces in the formation of HSA-Nano KMP and HTF-Nano KMP complexes. The thermodynamic parameter values of (HSA-HTF) Nano KMP revealed the dominance of hydrogen binding and van der Waals forces in the first set of binding sites and hydrophobic forces for the second set of binding sites. Resonance light scattering (RLS) analysis displayed the existence of a different interaction behavior for HSA-HTF complex in the presence of Nano-KMP as the ternary system. Moreover, circular dichroism (CD) technique affirmed the conformational changes of the secondary structure of proteins as binary and ternary systems. Molecular docking and molecular dynamics simulations (for 100 ns) were performed to investigate the mechanism of KMP binding to HSA, HTF, and HSA-HTF. Next to observing a concentration and time-dependent cytotoxicity, the down regulation of PI3K/AkT/mTOR pathway resulted in cell cycle arrest in SW480 cells.

Biophysical insights on the interaction of anticoagulant drug dicoumarol with calf thymus-DNA: deciphering the binding mode and binding force with thermodynamics

The biological activity of drugs is exhibited due to their interactions with bio-receptors. Dicoumarol (DIC) is a natural hydroxycoumarin and a well-known anticoagulant. DNA is the genetic material and one of the targets of numerous drugs. The interaction of DIC with calf-thymus DNA (ct-DNA) has been studied using different biophysical techniques and docking studies. The binding constant in the order of 103 to 104 M-1 was observed from spectroscopic studies. Thermodynamic studies at 4 different temperatures revealed the spontaneity of the interaction with the entropy-driven process. Marker displacement studies with competitive markers of intercalators (ethidium bromide) and groove binders (Hoechst 33258) confirmed the groove-binding nature of DIC in DNA. The groove-binding mode of DIC was complemented by different studies like viscosity measurements, DNA melting, and the effect of KI on the binding. A minor perturbation in the DNA viscosity and no significant change in the DNA melting temperature (Tm) after binding with DIC further confirms the groove binding mode. The effect of KI on the DIC and DIC-DNA system suggested the absence of DIC intercalation. The absence of significant electrostatic force was revealed from the ionic-strength effect study. Binding-induced conformational variation in ct-DNA was absent in circular dichroism studies. Molecular docking studies suggested the position of DIC within the minor groove of ct-DNA, covering three base pairs long. The outcome of this report may help in understanding the pharmacodynamics and pharmacokinetics of dicoumarol analogs and related molecules.Communicated by Ramaswamy H. Sarma.

Comparing the interactions of nitrendipine with lysozyme or human serum albumin and the effects of vitamin C and naringin on these interactions by spectroscopy and molecular docking methods

The interactions between drugs and proteins play a pivotal role in determining the pharmacological effects and disposition of drugs within the human body. This study focuses on exploring the interaction between nitrendipine and lysozyme/human serum albumin. Spectroscopic analysis indicated a compound static quenching, indicative of the formation of stable complexes between the drug and proteins. The addition of vitamin C or naringin resulted in a decrease of the binding constant between nitrendipine and lysozyme/human serum albumin. The presence of these compounds may disrupt the interactions between the drug and proteins, potentially leading to an increased concentration of free nitrendipine in the bloodstream. Nitrendipine binds more easily to human serum albumin at 310 K, and human serum albumin has an average binding site ratio with nitrendipine approximately 0.1 higher than that with lysozyme. Vitamin C has a greater impact on the binding constant of nitrendipine to human serum albumin and lysozyme. Compared to the binary system of proteins with the drug, the ternary system with the addition of vitamin C at 310 K reduces the binding constants of lysozyme and human serum albumin by 85%. In conclusion, this study explores the significance of considering drug-protein interactions in understanding drug behavior and potential drug-food interactions.

Assessment of the Binding of Pseudallecin A to Human Serum Albumin with Multi-Spectroscopic Analysis, Molecular Docking and Molecular Dynamic Simulation

The binding of pseudallecin A (PA), a potential antibiotic with strong inhibitory activities against Gram-positive Escherichia coli and Gram-negative Staphylococcus aureus, to human serum albumin (HSA) was explored. The interaction between them was assessed by multi-spectroscopic analysis, binding site competitive analysis, molecular docking and molecular dynamic simulation, showing the results as follows: PA effectively quenched the innate fluorescence of HSA by a static quenching process, formed a complex at a molar ratio of approximately 1 : 1 and performed an effective non-radiative energy transfer; the binding of PA to HSA was a spontaneous exothermic reaction driven by enthalpy with strong affinity and had a slight effect on the conformation of HSA; PA bound at site III of HSA and hydrogen bonds were the major binding forces to maintain the stability of the PA-HSA complex. Molecular dynamic simulation was performed to calculate the root mean square deviation (RMSD), root mean square fluctuation (RMSF) and radius of gyration (Rg) for this complex and effectively supported the spectroscopic outcome. These results meant that the delivery and distribution of PA as a water-insoluble molecule can be efficiently accomplished via HSA in human blood and, it has a good potential for future drug application and pharmacological development.

Binding of flavonoids to yeast aldehyde dehydrogenase: a molecular mechanism and computational approach

The interaction of three flavonoids, apigenin, fisetin and quercetin with yeast aldehyde dehydrogenase, ALDH was studied by spectroscopic and molecular docking methods. A combination of both static and dynamic processes interaction mechanism for the binding of flavonoids with ALDH was found. The interaction takes place with moderate binding and the interaction was driven by hydrophobic contacts. The microenvironments of the fluorescent amino acids changed upon flavonoids binding. The distances between ALDH and flavonoids determined by Förster Resonant Energy Transfer (FRET) confirmed the results obtained by fluorescence. The structure of ALDH against thermal denaturation was stabilized by apigenin and destabilized by fisetin and quercetin. Molecular docking simulation showed that all flavonoids bind to the same site of ALDH and confirmed the moderate binding straight found in fluorescence.Communicated by Ramaswamy H. Sarma.

Assessment on binding characteristics of ethiprole and a model protein bovine serum albumin (BSA) through various spectroscopic techniques integrated with computer simulation

To investigate the binding characteristics of pesticide ethiprole (ETP) with serum albumin is of great significance for pathological analysis of pesticide poisoning, gene mutation, and clinical detection. In present work, the binding characteristics of ETP with a model protein BSA has been estimated by means of multi-spectroscopic approaches integrated with computer simulation. The outcomes testified that the intrinsic fluorescence of BSA was mainly quenched by ETP in a static quenching mode and the stable ETP-BSA complex with the stoichiometry of 1:1 and the binding constant of 6.81 × 103 M-1 (298 K) was produced. The outcomes revealed that ETP combined preferentially to the subdomain IIA (Site I) of BSA and caused the decline in the content of α-helix of BSA and the enhancement in the hydrophobicity of environment centered on Trp residues. The outcomes of experimental and theoretical studies provide the sufficient evidence about the driving forces for the complexation of ETP with BSA, which included van der Waals forces (vdW), hydrogen bonding (H-bonding) interaction, and hydrophobicity. Simultaneously, the theoretical calculation results also confirmed the existence of the significant changes in the physicochemical natures of ETP including molecular conformation, dipole moment, frontier orbital energy, and the atomic charge distribution, which was a responsible for the complexation with BSA.Communicated by Ramaswamy H. Sarma.

Evaluation of the Possible Pathways Involved in the Protective Effects of Quercetin, Naringenin, and Rutin at the Gene, Protein and miRNA Levels Using In-Silico Multidimensional Data Analysis

Flavonoids are secondary metabolites that are non-essential for plant growth or survival, and they also provide numerous health benefits to humans. They are antioxidants that shield plants from the ill effects of ultraviolet light, pests, and diseases. They are beneficial to health for several reasons, including lowering inflammation, boosting cardiovascular health, and lowering cancer risk. This study looked into the physicochemical features of these substances to determine the potential pharmacological pathways involved in their protective actions. Potential targets responsible for the protective effects of quercetin, naringenin, and rutin were identified with SwissADME. The associated biological processes and protein-protein networks were analyzed by using the GeneMANIA, Metascape, and STRING servers. All the flavonoids were predicted to be orally bioavailable, with more than 90% targets as enzymes, including kinases and lyases, and with common targets such as NOS2, CASP3, CASP9, CAT, BCL2, TNF, and HMOX1. TNF was shown to be a major target in over 250 interactions. To extract the "biological meanings" from the MCODE networks' constituent parts, a GO enrichment analysis was performed on each one. The most important transcription factors in gene regulation were RELA, NFKB1, PPARG, and SP1. Treatment with quercetin, naringenin, or rutin increased the expression and interaction of the microRNAs' hsa-miR-34a-5p, hsa-miR-30b-5p, hsa-let-7a-5p, and hsa-miR-26a-1-3p. The anticancer effects of hsa-miR-34a-5p have been experimentally confirmed. It also plays a critical role in controlling other cancer-related processes such as cell proliferation, apoptosis, EMT, and metastasis. This study's findings might lead to a deeper comprehension of the mechanisms responsible for flavonoids' protective effects and could present new avenues for exploration.

Binding of dicoumarol analog with DNA and its antioxidant studies: A biophysical insight by in-vitro and in-silico approaches

DNA is the major target for a number of pharmaceutical drugs. The interaction of drug molecules with DNA plays a major role in pharmacokinetics and pharmacodynamics. Bis-coumarin derivatives have diverse biological properties. Here, we have explored the antioxidant activity of 3,3'-Carbonylbis (7-diethylamino coumarin) (CDC) using DPPH, H₂O_2, and superoxide scavenging studies followed by its binding mode in calf thymus-DNA (CT-DNA) using several biophysical methods including molecular docking. CDC exhibited comparable antioxidant activity to standard ascorbic acid. The UV-Visible and fluorescence spectral variations indicate the CDC-DNA complex formation. The binding constant in the range of 10⁴ M^-1 was obtained from spectroscopic studies at room temperature. The fluorescence quenching of CDC by CT-DNA suggested a quenching constant (K_SV) of 10³ to 10⁴ M^-1 order. Thermodynamic studies at 303, 308, and 318 K revealed the observed quenching as a dynamic process besides the spontaneity of the interaction with negative free energy change. Competitive binding studies with site markers like ethidium bromide, methylene blue, and Hoechst 33258 reflect CDC's groove mode of interaction. The result was complemented by DNA melting study, viscosity measurement, and KI quenching studies. The ionic strength effect was studied to interpret the electrostatic interaction and found its insignificant role in the binding. Molecular docking studies suggested the binding location of CDC within the minor groove of CT-DNA, complementing the experimental result.

Probing the binding of morin with alpha-2-macroglobulin using multi-spectroscopic and molecular docking approach : Interaction of morin with α2M

Alpha-2-macroglobulin (α2M) is an essential antiproteinase that is widely distributed in human plasma. The present study was aimed at investigating the binding of a potential therapeutic dietary flavonol, morin, with human α2M using a multi-spectroscopic and molecular docking approach. Recently, flavonoid-protein interaction has gained significant attention, because a majority of dietary bioactive components interact with proteins, thereby altering their structure and function. The results of the activity assay exhibited a 48% reduction in the antiproteolytic potential of α2M upon interaction with morin. Fluorescence quenching tests unequivocally confirmed quenching in the fluorescence of α2M in the presence of morin, conforming complex formation and demonstrating that the binding mechanism involves a dynamic mode of interaction. Synchronous fluorescence spectra of α2M with morin showed perturbation in the microenvironment around tryptophan residues. Furthermore, structural changes were observed through CD and FT-IR, showing alterations in the secondary structure of α2M induced by morin. FRET further supports the results of the dynamic mode of quenching. Moderate interaction is shown by binding constant values using Stern-Volmer's fluorescence spectroscopy. Morin binds to α2M at 298 K with a binding constant of 2.7 × 104 M-1, indicating the strength of the association. The α2M-morin system was found to have negative ΔG values, which suggests that the binding process was spontaneous. Molecular docking also reveals the different amino acid residues involved in this binding process, revealing that the binding energy is -8.1 kcal/mol.

Toxicity Study and Binding Analysis of Newly Synthesized Antifungal N-(4-aryl/cyclohexyl)-2-(pyridine-4-yl carbonyl) hydrazinecarbothioamide Derivative with Bovine Serum Albumin

The presence of the p-aryl/cyclohexyl ring in the N-(4-aryl/cyclohexyl)-2-(pyridine-4-yl carbonyl) hydrazine carbothioamide derivative (2C) is reported to enhance the antifungal properties when compared to those of itraconazole. Serum albumins present in plasma bind and transport ligands, including pharmaceuticals. This study explored 2C interactions with BSA using spectroscopic methods such as fluorescence and UV-visible spectroscopy. In order to acquire a deeper comprehension of how BSA interacts with binding pockets, a molecular docking study was carried out. The fluorescence of BSA was quenched by 2C via a static quenching mechanism since a decrease in quenching constants was observed from 1.27 × 10⁵ to 1.14 × 10⁵. Thermodynamic parameters indicated hydrogen and van der Waals forces responsible for the BSA-2C complex formation with binding constants ranging between 2.91 × 10⁵ and 1.29 × 10⁵, which suggest a strong binding interaction. Site marker studies displayed that 2C binds to BSA's subdomains IIA and IIIA. Molecular docking studies were conducted to further comprehend the molecular mechanism of the BSA-2C interaction. The toxicity of 2C was predicted by Derek Nexus software. Human and mammalian carcinogenicity and skin sensitivity predictions were associated with a reasoning level of equivocal, inferring 2C to be a potential drug candidate.

Potential toxic effects of sulfonamides antibiotics: Molecular modeling, multiple-spectroscopy techniques and density functional theory calculations

Sulfonamide antibiotics (SAs) are widely used in medicine, animal husbandry and aquaculture, and excessive intake of SAs may pose potential toxicity to organisms. The toxicological mechanisms of two classical SAs, sulfamerazine (SMR) and sulfamethoxazole (SMT), were investigated by molecular docking, DFT and multi-spectroscopic techniques using HSA and BSA as model proteins. The quenching of HSA/BSA endogenous fluorescence by SMR was higher than that by SMT due to the stronger binding effect of the pyrimidine ring on HSA/BSA compared to the oxazole ring, and that result was consistent with that predicted by DFT calculations. Thermodynamic parameters show that the binding of SAs to HSA/BSA is an exothermic process that proceeds spontaneously (ΔG < 0). Marker competition experiments illustrate that the binding site of SMR/SMT on serum albumin is located in subdomain IIIA. The combination of SAs and HSA/BSA is mainly realized by hydrogen bond and hydrophobic interaction, and the concept is also supported by molecular modeling. The reduced α-helix content of HSA/BSA induced by SMR/SMT indicates a greater stretching of the protein α-helix structure of the SMR/SMT-HSA/BSA. The results could provide useful toxicological information on the hazards of SAs in response to growing concern that SAs may pose a toxic threat to organisms.

Deciphering the nature of binding of dexlansoprazole with DNA: Biophysical and docking approaches

Drugs, in general, exhibit their pharmacological activity in binding with intracellular targets. Numerous anticancer and antibacterial drugs target DNA as one of their primary intracellular targets. Dexlansoprazole (DLP) is a heterocyclic compound containing benzimidazole moiety and a proton pump inhibitor used to treat gastroesophageal reflux disease. The interaction of dexlansoprazole with calf thymus DNA (ct-DNA) has been studied using biophysical methods. The UV-Visible studies revealed a binding constant of 2.15 ± 0.3 × 104 M^-1 which is close to the value of 2.44 ± 0.3 × 10⁴ M^-1 obtained from the fluorescence studies. Competitive displacement studies using the fluorescence spectroscopic method with ethidium bromide and Hoechst as DNA markers suggested the groove binding mode of DLP in ct-DNA. The groove binding mode of DLP in ct-DNA was complemented by the results of viscosity and DNA melting studies. Further studies on the effect of ionic strength and potassium iodide on DLP binding with ct-DNA supported the observed binding mode. Circular dichroism studies reflected no significant conformational variation in ct-DNA after the interaction. The binding mode obtained from the experimental studies was corroborated by the molecular docking studies that showed the position of DLP in the minor groove of ct-DNA along with the receptor interface restudies involved in the interaction.

An insight into the interaction between Indisulam and human serum albumin: Spectroscopic method, computer simulation and in vitro cytotoxicity assay

Indisulam (IDM) is a sulfanilamide anticancer agent and has been identified as a molecular glue recently. It shows potential for novel therapies development and brings more hope for curing human diseases. The affinity between molecular glues and plasma protein makes it significant to understand the characteristics of such substances. Therefore, the interaction between IDM and human serum albumin (HSA) was explored through solvent experiments, computer simulation experiments, enzyme kinetics experiments, and cell viability assay. The results revealed that IDM and HSA spontaneously formed stable binary complex with the binding constant of the order 10⁵ M^-1. IDM inserted in the site I of HSA, resulting the change in HSA secondary structure. And π electrons in IDM's benzene rings, as well as van der Waals forces and the H-bond, all helped to stabilize the HSA-IDM complex. The results of molecular dynamic simulation (MD) corresponded with the results from solvent experiment well. For instance, there were approximately 1-5 H-bonds between IDM and HSA. Lys199 and Arg218 were crucial energy contributors in the binding process. The esterase-like activity experiment confirmed that IDM inhibited the catalytic activity of HSA. In addition, cell experiment revealed that serum albumin can significantly reduce the cytotoxicity of IDM towards human embryonic kidney 293T (HEK293T) cells.

Association Mechanism and Conformational Changes in Trypsin on Its Interaction with Atrazine: A Multi- Spectroscopic and Biochemical Study with Computational Approach

Atrazine (ATR) is a herbicide globally used to eliminate undesired weeds. Herbicide usage leads to various adverse effects on human health and the environment. The primary source of herbicides in humans is the food laced with the herbicides. The ATR binding to trypsin (TYP) was investigated in this study to explore its binding potential and toxicity. In vitro interaction of ATR with TYP was studied using multi-spectroscopic methods, molecular docking, and enzyme kinetics to explore the mechanism of binding for the TYP-ATR system. The TYP-ATR complex revealed binding constants (10³ M^-1), suggesting a moderate binding. The free energy for the TYP-ATR complexes was negative, suggesting a spontaneous interaction. Thermodynamic parameters enthalpy (ΔH) and entropy (ΔS) obtained positive values for the TYP-ATR system suggesting hydrophobic interactions in the binding process. Micro-environmental and conformational changes in TYP molecules were induced on interaction with ATR. Reduced catalytic activity of TYP was observed after interaction with ATR owing to the changes in the secondary structure of the TYP.

A Comprehensive Investigation of Interactions between Antipsychotic Drug Quetiapine and Human Serum Albumin Using Multi-Spectroscopic, Biochemical, and Molecular Modeling Approaches

Quetiapine (QTP) is a short-acting atypical antipsychotic drug that treats schizophrenia or manic episodes of bipolar disorder. Human serum albumin (HSA) is an essential transport protein that transports hormones and various other ligands to their intended site of action. The interactions of QTP with HSA and their binding mechanism in the HSA-QTP system was studied using spectroscopic and molecular docking techniques. The UV-Vis absorption study shows hyperchromicity in the spectra of HSA on the addition of QTP, suggesting the complex formation and interactions between QTP and HSA. The results of intrinsic fluorescence indicate that QTP quenched the fluorescence of HSA and confirmed the complex formation between HSA and QTP, and this quenching mechanism was a static one. Thermodynamic analysis of the HSA-QTP system confirms the involvement of hydrophobic forces, and this complex formation is spontaneous. The competitive displacement and molecular docking experiments demonstrated that QTP is preferentially bound to HSA subdomain IB. Furthermore, the CD experiment results showed conformational changes in the HSA-QTP system. Besides this, the addition of QTP does not affect the esterase-like activity of HSA. This study will help further understand the credible mechanism of transport and delivery of QTP via HSA and design new QTP-based derivatives with greater efficacy.