Weak Binding Research Articles

Glycoconjugate Vaccines: Platforms and Adjuvants for Directed Immunity.

Central to immune recognition is the glycocalyx, a glycan-rich coat on all cells that plays a crucial role in interactions that enable pathogen detection and activation of immune defenses. Pathogens and cancerous cells often display distinct glycans on their surfaces, making these saccharide antigens prime targets for vaccine development. However, carbohydrates alone generally serve as poor immunogens due to their often weak binding affinities, inability to effectively recruit T cell help, and reliance on adjuvants to induce immune activation. The introduction of glycoconjugate vaccines, initially involving the covalent coupling of carbohydrate antigens to carrier proteins, marked a pivotal advancement by facilitating neutralizing antibody production against these carbohydrate targets. Despite successes in generating glycoconjugate vaccines against certain bacterial diseases, challenges persist in creating effective vaccines against numerous intracellular pathogens and non-communicable diseases such as cancer. New developments in conjugate vaccine platforms aim to overcome these limitations by optimizing the display of glycan and T cell epitope as well as incorporating defined carbohydrate adjuvants to direct tailored immune responses. These advancements promise to improve the effectiveness of carbohydrate-based vaccines and broaden their coverage against a wide range of diseases.

Facet-Dependent Photocatalytic CO2 Reduction on TiO2 Crystals in the Presence of SO2: Role of Surface Hydroxyl.

Photocatalytic CO2 reduction to solar energy makes great sense to mitigate the greenhouse effect caused by CO2, and great efforts have been made to promote CO2 conversion efficiency. However, the effect of impurities in the photoreduction of CO2 has received relatively little attention. Here, the different CO2 photoreduction behaviors of TiO2 exposed (101) facet (TiO2-101) and (001) facet (TiO2-001) with an SO2 impurity were investigated. On TiO2-101, SO2 accelerates the deactivation of the catalyst for CO2 photoreduction activity, since SO2 mainly binds to the OHb site of TiO2-101. This site is highly susceptible to the transfer of photogenerated holes, resulting in the rapid generation of SO42-, which occupies the active site and poisons the catalyst. For TiO2-001, SO2 has relatively little negative effect on stability, as SO2 mainly binds to the weak binding site (OHt) of TiO2-001, preventing it from being oxidized to SO42-, which alleviates catalyst deactivation and ensures the continuity of CO2 reduction. This paper provides further insights into the role of SO2 in CO2 photoreduction over distinct TiO2 facets and reveals the importance of facet engineering in the photocatalytic reduction of CO2 from industrial flue gas.

Complexity associated with caprylate binding to bovine serum albumin: Dimerization, allostery, and variance between the change in free energy and enthalpy of binding.

Isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), and pressure perturbation calorimetry (PPC) were used to study different aspects of the diverse interaction between the fatty acid caprylate and bovine serum albumin (BSA). The ITC thermogram was consistent with exothermic binding to a single site on BSA, which was electrostatic but had little or no hydrophobic contribution. ITC revealed that small changes to solution conditions and temperature were associated with apparent enthalpy-entropy compensation, causing large changes in enthalpy (ΔH) during binding, but with little corresponding changes in free energy (ΔG). ITC also detected a slower endothermic interaction at a low mole ratio. Dynamic light scattering suggested that this was due to dimerization or similar self-association. DSC demonstrated that further interactions took place at higher mole ratios. This was consistent with weak binding of caprylate to multiple binding sites which had a considerable impact on the structural conformation of BSA. PPC showed that the conformational change of BSA was accompanied with a reduction in surface hydrophobicity of the protein. PPC also demonstrated that in solution caprylate's hydrocarbon tail is hidden from water as no clathrate-like water is evident, which is consistent with the lack of hydrophobic contribution during binding. Cumulatively, the three calorimetric techniques offer a comprehensive view of caprylate and BSA interactions, highlighting the role of electrostatic interaction in binding accompanied by probably dimerization and considerable structural change associated with weaker binding to BSA.

Multivalent Weak Protections Ultimately Enable Customizable DNA Grafting on Pristine Ag Colloids for Nanoplasmonics

AbstractSilver nanoparticles (AgNPs) have superior plasmonic properties surpassing other metals. However, a long‐standing difficulty in valence/density‐tunable DNA grafting of AgNPs disfavors their use in DNA‐directed nanoplasmonics. Herein a close‐to‐ideal surface protection of pristine AgNPs against various notorious stability issues of Ag is achieved based on multidentate weak nucleobase bindings of non‐programming FSDNA (fish sperm DNA). This further allows grafting of thiolated DNA with tunable valence/density on AgNPs. The end‐on format of the thiolated DNA grafts and the very thin FSDNA layer benefit DNA hybridization and plasmon coupling, respectively. Significantly promoted optical coupling and Raman enhancing are achieved. The compatibility of FSDNA‐capped AgNPs with Au enables DNA‐bonded symmetry‐broken Au−Ag heterodimers with strong near‐field coupling and an easily seen Fano‐induced feature. Our work provides a treasured freedom of using AgNPs in DNA‐programmed, better‐behaving plasmonic devices.

A DFT study on the role of excitons and electric field-induced symmetry breaking and topological properties of ZrBr

The control of band gap and topological properties is a crucial objective in the field of materials science, particularly for the application of 2D materials such as topological insulators. Zirconium monobromide (ZrBr), a topological insulator with band inversion, holds significant potential for various applications. In this study, we used Density Functional Theory (DFT) with different approximations namely, Generalized Gradient Approximation (GGA) with and without spin orbit coupling (SOC) as well as hybrid functional to investigate the electronic structure and the band gap of this compound. In addition, we introduced the excitonic effect by considering GW plus Bethe–Salpeter equation (GW-BSE) to compute the optical band gap and quasi-particle energy. We found that ZrBr present a low static dielectric function and weak exciton binding energy, generally lower than those of conventional semiconductors. This behavior is due to the reduced Coulomb interaction in the material. To further explore the material’s behavior, we apply an electric field in three directions to observe symmetry breaking and its impact on band gap tuning. This comprehensive analysis aims to explore the understanding and the potential applications of ZrBr as a topological insulator.

Fluorescent Aerolysin (FLAER) Binding Is Abnormally Low in the Clonal Precursors of Acute Leukemias, with Binding Particularly Low or Absent in Acute Promyelocytic Leukemia.

Flow cytometry plays a fundamental role in the diagnosis of leukemias and lymphomas, as well as in the follow-up and evaluation of minimally measurable disease after treatment. In some instances, such as in the case of acute promyelocytic leukemia (APL), rapid diagnosis is required to avoid death due to serious blood clotting or bleeding complications. Given that promyelocytes do not express the glycophosphatidylinositol (GPI)-anchored protein CD16 and that deficient CD16 expression is a feature of some CD16 polymorphisms and paroxysmal nocturnal hemoglobinuria (PNH), we included the GPI anchor probe FLAER aerolysin in the APL flow cytometry probe panel. Initial tests showed that FLAER binding was absent in pathological promyelocytes from APL patients but was consistently detected with high intensity in healthy promyelocytes from control bone marrow. FLAER binding was studied in 71 hematologic malignancies. Appropriate control cells were obtained from 16 bone marrow samples from patients with idiopathic thrombocytopenic purpura and non-infiltrated non-Hodgkin's lymphoma. Compared with the positive FLAER signal in promyelocytes from healthy bone marrow, malignant promyelocytes from APL patients showed weak or negative FLAER binding. The FLAER signal in APL promyelocytes was also lower than that in control myeloid progenitors and precursors from patients with other forms of acute myeloid leukemia (AML), B-cell acute lymphoblastic leukemia, or myelodysplastic syndrome. Minimal measurable disease studies performed in APL patients after treatment found normal promyelocyte expression when minimal measurable disease was negative and FLAER-negative promyelocytes when disease relapse was detected. The inclusion of FLAER in the flow cytometry diagnosis and follow-up of APL could be very helpful. Decreased FLAER binding was found in all cases of APL, confirmed by the detection of the PML-RARA fusion transcript and, to a lesser extent, in the other AMLs studied. This study also revealed FLAER differences in other acute leukemias and even between different precursors (myeloid and lymphoid) from healthy controls. However, the reason for FLAER's non-binding to the malignant precursors of these leukemias remains unknown, and future studies should explore the possible relation with an immune escape phenomenon in these leukemias.

ABTrans: A Transformer-based Model for Predicting Interaction between Anti-Aβ Antibodies and Peptides.

Antibodies against Aβ peptide have been recently approved to treat Alzheimer's disease, underscoring the importance of understanding their interactions for developing more potent treatments. Here we investigated the interaction between anti-Aβ antibodies and various peptides using a deep learning model. Our model, ABTrans, was trained on dodecapeptide sequences from phage display experiments and known anti-Aβ antibody sequences sourced from public sources. It classified the binding ability between anti-Aβ antibodies and dodecapeptides into four levels: not binding, weak binding, medium binding, and strong binding, achieving an accuracy of 0.83. Using ABTrans, we examined the cross-reaction of anti-Aβ antibodies with other human amyloidogenic proteins, revealing that Aducanumab and Donanemab exhibited the least cross-reactivity. Additionally, we systematically screened interactions between eleven selected anti-Aβ antibodies and all human proteins to identify potential off-target candidates.

Comparison of Methodologies for Absolute Binding Free Energy Calculations of Ligands to Intrinsically Disordered Proteins.

Modulating the function of Intrinsically Disordered Proteins (IDPs) with small molecules is of considerable importance given the crucial roles of IDPs in the pathophysiology of numerous diseases. Reported binding affinities for ligands to diverse IDPs vary broadly, and little is known about the detailed molecular mechanisms that underpin ligand efficacy. Molecular simulations of IDP ligand binding mechanisms can help us understand the mode of action of small molecule inhibitors of IDP function, but it is still unclear how binding energies can be modeled rigorously for such a flexible class of proteins. Here, we compare alchemical absolute binding free energy calculations (ABFE) and Markov-State Modeling (MSM) protocols to model the binding of the small molecule 10058-F4 to a disordered peptide extracted from a segment of the oncoprotein c-Myc. The ABFE results produce binding energy estimates that are sensitive to the choice of reference structure. In contrast, the MSM results produce more reproducible binding energy estimates consistent with weak mM binding affinities and transient intermolecular contacts reported in the literature.

Improving the interfacial bonding strength of a silane anticorrosion film on copper surfaces using small-molecule corrosion inhibitors

The weak binding ability of silane to copper surfaces restricts its use in copper anticorrosion. In this study, the P–OH groups in etidronic acid (HEDP) were utilized to establish chemical bonds with copper and to react with 3-mercaptopropyltrimethoxysilane (PropS-SH), serving as a bridging mechanism to enhance the anchoring of silane onto copper surfaces. Moreover, the presence of HEDP promoted the condensation of silane, leading to the formation of a denser and thicker film with outstanding corrosion resistance. SEM results indicated that the thickness of the PropS-SH/HEDP film was about 125 nm, and defects at the copper–film interface were repaired. Electrochemical tests demonstrated that the PropS-SH/HEDP film exhibited remarkable corrosion resistance, achieving an anticorrosion efficiency of 99.95 %. Immersion testing showed that the PropS-SH/HEDP film was capable of withstanding immersion in a 3.5 wt% NaCl solution for 10 days, displaying a durability 5 times greater than that of the standalone silane film.

Unconventional Electrocatalytic CO Conversion to C2 Products on Single-Atomic Pd-Agn Sites.

The electrochemical reduction of CO or CO2 into C2+ products has mostly been focused on Cu-based catalysts. Although Ag has also been predicted as a possible catalyst for the CO-to-C2+ conversion from the thermodynamic point of view, however, due to its weak CO binding strength, CO rapidly desorbs from the Ag surface rather than participates in deep reduction. In this work, we demonstrate that single-atomic Pd sites doped in Ag lattice can tune the CO adsorption behavior and promote the deep reduction of CO toward C2 products. The monodispersed Pd-Agn sites enable the CO adsorption with both Pd-atop (PdL) and Pd-Ag bridge (PdAgB) configurations, which can increase the CO coverage and reduce the C-C coupling energy barrier. Under room temperature and ambient pressure, the Pd1Ag10 alloy catalyst exhibited a total CO-to-C2 Faradaic efficiency of ~37 % at -0.83 V, with appreciable current densities and electrochemical stability, thus featuring unconventional non-Cu electrocatalytic CO-to-C2 conversion capability.

Enhancing mRNA Interactions by Engineering the Arc Protein with Nucleocapsid Domain.

Activity-regulated cytoskeleton-associated protein (Arc) forms virus-like capsids for mRNA transport between neurons. Unlike HIV-1 Group-specific Antigen (Gag), which uses its Nucleocapsid (NC) domain to bind HIV-1 genomic mRNA, mammalian Arc lacks the NC domain, and their direct mRNA binding interactions remain underexplored. This study examined rat Arc's binding to rat Arc 5' UTR (A5U), HIV-1 5' UTR (H5U), and GFP mRNAs, revealing weak binding with no significant preference. Adding the HIV-1 NC domain to rArc's C-terminus significantly improved binding to H5U, while also showing substantial binding to A5U at about 60% of its H5U level and exhibiting twice the affinity for A5U over GFP mRNA. Importantly, rArc-NC binds 3.4 times more A5U and H5U than GST-NC, indicating that rArc NTD-CA aids mRNA binding by HIV-1 NC. These findings suggest a conserved Gag protein-mRNA interaction mechanism, highlighting the potential for developing mRNA delivery systems that combine endogenous Gag NTD-CA with retroviral NC and UTRs.

A diarylheptanoid derivative mediates glycogen synthase kinase 3β to promote the porcine muscle satellite cell proliferation: Implications for cultured meat production

Skeletal muscle stem cells, or satellite cells, are vital for cultured meat production, driving proliferation and differentiation to form muscle fibers in vitro. However, these abilities are often compromised after long-term in vitro culturing due to a loss of their stemness characteristics. Therefore, effective pharmacological agents that enhance satellite cell proliferation and maintain stemness ability are needed for optimal cell growth for cultured meat production. In this study, the effects of the identified glycogen synthase kinase 3β (GSK3β) inhibitors, ASPP 049, a diarylheptanoid isolated from Curcuma comosa rhizomes, and CHIR 99021 on porcine muscle satellite cell (PMSC) proliferation and Wnt/β-catenin signaling pathway were investigated. We found that both compounds enhanced cell viability and proliferation while preserving the stemness marker, as evidenced by increased expression of the skeletal muscle stem cell marker, Pax7 protein. Molecular dynamics simulations showed that ASPP 049 and CHIR 99021 exhibited differing binding affinities, primarily through hydrophobic interactions, suggesting potential for the design of more potent inhibitors in the future. Despite its weaker binding, ASPP 049 still showed significant effects on the regulation of the Wnt/β-catenin signaling pathway via increased phosphorylation of GSK3β at Ser9 and decreased the phosphorylation of β-catenin at Ser33, Ser37, and Thr41, thereby subsequently activating Wnt transcriptional activity. This study highlights the potential of ASPP 049 and CHIR 99021 to enhance PMSC proliferation and maintain stemness ability, offering a promising avenue for improving cultured meat production.

Adsorption of Ag, Au, Cu, and Ni on MoS2: theory and experiment

Here, we present results of a computational and experimental study of adsorption of various metals on MoS2. In particular, we analyzed the binding mechanism of four metallic elements (Ag, Au, Cu, Ni) on MoS2. Among these elements, Ni exhibits the strongest binding and lowest mobility on the surface of MoS2. On the other hand, Au and Ag bond very weakly to the surface and have very high mobilities. Our calculations for Cu show that its bonding and surface mobility are between these two groups. Experimentally, Ni films exhibit a composition characterized by randomly oriented nanoscale clusters. This is consistent with the larger cohesive energy of Ni atoms as compared with their binding energy with MoS2, which is expected to result in 3D clusters. In contrast, Au and Ag tend to form atomically flat plateaued structures on MoS2, which is contrary to their larger cohesive energy as compared to their weak binding with MoS2. Cu displays a surface morphology somewhat similar to Ni, featuring larger nanoscale clusters. However, unlike Ni, in many cases Cu exhibits small plateaued surfaces on these clusters. This suggests that Cu likely has two competing mechanisms that cause it to span the behaviors seen in the Ni and Au/Ag film morphologies. These results indicate that calculations of the initial binding conditions could be useful for predicting film morphologies. In addition, out calculations show that the adsorption of adatoms with odd electron number like Ag, Au, and Cu results in 100% spin-polarization and integer magnetic moment of the system. Adsorption of Ni adatoms, with even electron number, does not induce a magnetic transition.

Observation of Three-Photon Cascaded Emission from Triexcitons in Giant CsPbBr3 Quantum Dots at Room Temperature.

Colloidal semiconductor nanocrystals have long been considered a promising source of time-correlated and entangled photons via the cascaded emission of multiexcitonic states. The spectroscopy of such cascaded emission, however, is hindered by efficient nonradiative Auger-Meitner decay, rendering multiexcitonic states nonemissive. Here we present room-temperature heralded spectroscopy of three-photon cascades from triexcitons in giant CsPbBr3 nanocrystals. We show that this system exhibits second- and third-order correlation function values, g(2)(0) and g(3)(0,0), close to unity, identifying very weak binding of both biexcitons and triexcitons. Combining fluorescence lifetime analysis, photon statistics, and spectroscopy, we can readily identify emission from higher multiexcitonic states. We use this to verify emission from a single emitter despite high emission quantum yields of multiply excited states and comparable emission lifetimes of singly and multiply excited states. Finally, we present potential pathways toward control of the photon number statistics of multiexcitonic emission cascades.

Is Public Participation Weak Environmental Regulation? Experience from China’s Environmental Public Interest Litigation Pilots

Previous studies have generally concluded that public participation lacks substantive constraints and has weak environmental regulation effects. Using China’s environmental public interest litigation (EPIL), implemented in 2015, as a quasi-natural experiment to verify the environmental effects of public participation under judicial norms, the difference-in-differences (DID) estimates in this paper show that industrial wastewater and industrial sulfur dioxide (SO2) emissions in the treated cities declined by an average of 2.76 million tons and 2.51 kilotons per year, respectively, which ultimately improved the city’s environmental quality. The results of the mechanism also show that the EPIL was able to mobilize all three parties: the public, government and enterprises. In the context of the environment as an externality product, where the interests of all the parties are difficult to coordinate, the EPIL has the advantage of overcoming conflicts of interest. Our study provides a quantitative justification for the environmental impact assessment of public litigation and contributes empirical references to overcome the weak binding defect of public participatory environmental regulation.

Allosteric degraders induce CRL5 ASB8 mediated degradation of XPO1.

The nuclear export receptor Exportin 1 (XPO1/CRM1) is often overexpressed in cancer cells resulting in aberrant localization of many cancer-related protein cargoes. The XPO1 inhibitor and cancer drug selinexor (KPT-330), and its analog KPT-185, block XPO1-cargo binding thereby restoring cargo localization. Selinexor binding induces cullin-RING E3 ubiquitin ligase (CRL) substrate receptor ASB8-mediated XPO1 degradation. Here we reveal the mechanism of inhibitor-XPO1 engagement by CRL5ASB8. Cryogenic electron microscopy (cryo-EM) structures show ASB8 binding to a large surface of selinexor/KPT-185-XPO1 that includes a three-dimensional degron unique to the drug-bound exportin. The structure explains weak XPO1-ASB8 binding in the absence of selinexor/KPT-185 that is unproductive for proteasomal degradation, and the substantial affinity increase upon selinexor/KPT-185 conjugation, which results in CRL5 ASB8 -mediated XPO1 ubiquitination. In contrast to previously characterized small molecule degraders, which all act as molecular glues, selinexor/KPT-185 binds extensively to XPO1 but hardly contacts ASB8. Instead, selinexor/KPT-185 binds XPO1 and stabilizes a unique conformation of the NES/inhibitor-binding groove that binds ASB8. Selinexor/KPT-185 is an allosteric degrader. We have explained how drug-induced protein degradation is mediated by a CRL5 system through an allosteric rather than a molecular glue mechanism, expanding the modes of targeted protein degradation beyond the well-known molecular glues of CRL4.

Afadin mediates cadherin-catenin complex clustering on F-actin linked to cooperative binding and filament curvature.

The E-cadherin-β-catenin-αE-catenin (cadherin-catenin) complex couples the cytoskeletons of neighboring cells at adherens junctions (AJs) to mediate force transmission across epithelia. Mechanical force and auxiliary binding partners converge to stabilize the cadherin-catenin complex's inherently weak binding to actin filaments (F-actin) through unclear mechanisms. Here we show that afadin's coiled-coil (CC) domain and vinculin synergistically enhance the cadherin-catenin complex's F-actin engagement. The cryo-EM structure of an E-cadherin-β-catenin-αE-catenin-vinculin-afadin-CC supra-complex bound to F-actin reveals that afadin-CC bridges adjacent αE-catenin actin-binding domains along the filament, stabilizing flexible αE-catenin segments implicated in mechanical regulation. These cooperative binding contacts promote the formation of supra-complex clusters along F-actin. Additionally, cryo-EM variability analysis links supra-complex binding along individual F-actin strands to nanoscale filament curvature, a deformation mode associated with cytoskeletal forces. Collectively, this work elucidates a mechanistic framework by which vinculin and afadin tune cadherin-catenin complex-cytoskeleton coupling to support AJ function across varying mechanical regimes.

Fabrication of PVC-based electromagnetic interference shielding composite film by positively charged SMA enhancing the dispersibility of carbon nanomaterial

To address the weak binding force and poor dispersion stability of carbon (C) nanoparticles in current non-covalent modification methods, we employed organic amine-grafted styrene maleic anhydride copolymers (SMA-N) to modify C nanoparticles (C@SMA-N) through π–π conjugation and positive charge interactions. The obtained C@SMA-N has excellent dispersion in N, N-dimethylacetamide (DMAc), which is attributed to the enhanced steric hindrance and electrostatic repulsion from the grafted organic amine chains. To study the impact of surface modification on the electromagnetic interference shielding effectiveness (EMI SE), C@SMA-N was used as a conductive filler in polyvinyl chloride (PVC) composite films, which exhibits a higher EMI SE performance than pristine C nanoparticles. Particularly, the obtained C@SMA-N using polyether amine (PEA) (C@SMA-PEA) exhibits a better EMI SE performance. By optimizing the SMA-PEA grafting parameters, the PVC/C@SMA-PEA composite films transition from insulators to conductors at a C@SMA-PEA content of 0.3 wt%. To achieve a higher EMI SE performance, the filler content, mixed filler composition, and film thickness were optimized. The results indicate that with a total filler content of 20 wt% and a mixed filler comprising fibrous form carbon nanotubes (CNT) and particles form carbon black (CB) in a 10:1 mass ratio (CB@SMA-PEA to CNT@SMA-PEA), the composite film has a thickness of 0.08 mm and an EMI SE value of 20.2 dB. Increasing the thickness to 0.2 mm enhances the EMI SE value to 31.5 dB. These findings indicate that thinner films have a higher EMI SE performance and promising application prospects in the field of electromagnetic shielding.

Cobaltabis(dicarbollide) Interaction with DNA Resolved at the Atomic Scale.

Boron neutron capture therapy represents a promising avenue for cancer treatment that requires nontoxic drugs with a high boron content efficiently distributed into cancerous cells. The metallacarborane o-cobaltabis(dicarbollide) ([COSAN]-) fulfills these requirements and constitutes an attractive candidate. Nevertheless, the interaction of this promising drug with nucleic acids, the assumed target of the biological damage, is poorly understood since contradictory results are reported in the literature. This work establishes the DNA/[COSAN]- interaction strength, mechanism, and time scale at the atomistic level by using a combination of microsecond-molecular dynamics and hybrid quantum mechanics/molecular mechanics simulations and by quantifying the absolute binding free energy. Results show that the DNA/[COSAN]- interaction is highly dependent on the ionic strength of the medium. A relatively weak DNA major groove binding (ΔGbind= -2.49 kcal/mol) driven mostly by dihydrogen B-H···H-N bonding is observed in the simulations only at a high NaCl concentration, whereas DNA intercalation mode is deemed highly unlikely.

Investigation of the molecular interaction between apraclonidine, an α2-adrenergic receptor agonist, and bovine serum albumin using fluorescence and molecular docking techniques

Apraclonidine (APR) is a potent and selective α2-adrenergic receptor agonist used in the diagnosis of Horner’s Syndrome, and the residuals of APR that accumulate in tissues of animals can cause central nervous and cardiovascular systems influences in humans. Therefore, to understand the influence of APR on human health, we examined the interaction of APR with the carrier protein in plasma, bovine serum albumin (BSA). The BSA fluorescence signal was quenched due to the APU–BSA complex formation and a weak binding affinity was estimated between APR and BSA. The inclusion of fluorescence, UV–vis absorption, molecular docking, and dynamics simulation techniques employed to broadly investigate the combination of APR with BSA at typical physiological conditions. The thermodynamic results revealed that enthalpy (ΔH0) and entropy (ΔS0) changes were computed as +11.14 kJ mol−1 and +97.56 J mol−1 K−1, respectively, which represented the binding is principally entropy-driven and the hydrophobic forces acting a significant role in the reaction. Analysis of synchronous and 3-D fluorescence signals revealed microenvironmental variations close to BSA’s Trp and Tyr residues upon APR addition. Both the competitive site marker as well as molecular docking results detected that APR exhibited a stronger binding affinity towards Drug Site 2 (DS2) compared to Drug Site 1 (DS1).