Synergistic Binding Research Articles

Pillar[5]arene-based Polymer Network for Efficiently Removing Perfluorooctanoic Acid through Synergistic Binding Interactions.

Perfluorooctanoic acid (PFOA) is currently one of the most important chemicals posing environmental risks, and there is an urgent need to find methods to efficiently remove PFOA from environmental media. Here, two decaamino-pillar[5]arene-based fluorine-rich polymer networks, called FA2P-P and FA6P-P, were constructed using a convenient method. FA6P-P had an excellent ability to take up PFOA, and had a capacity of 1423 (mg PFOA) (g FA6P-P)-1, which is the second highest adsorption capacity reported for any PFOA sorbent. FA6P-P removed >99 % of the PFOA from a solution and decreased the PFOA concentration from 1000 μg L-1 in 5 min at an exceedingly low adsorbent loading of 0.7 mg L-1, giving a final PFOA concentration <4 ng L-1, which is lower than the most recent enforceable maximum concentration set by the United States Environmental Protection Agency. A high rate constant (kobs) of 55.8 g mg-1 h-1 was observed. Pillar[5]arene gives the material hydrophobic properties and also amino sites and hydrophobic chains, which are synergistic PFOA binding sites. The polymer was very stable and readily regenerated. The results indicated that pillar[5]arene-based porous organic polymer sorbents are excellent candidates for capturing PFOA.

Unraveling latent affinity of strategically designed histidine-rich biosurfactant via tannery waste bio-upcycling in environmentally-relevant lignin removal from pulp and paper industry effluent

Bioremediation of pulp and paper industry (PPI) effluent is hindered due to biorefractory lignin. Herein, we demonstrate a lignin-specific designer biosurfactant with synergistic binding sites for enhanced lignin removal from PPI effluent. The histidine rich-cationic lipoprotein biosurfactant (HR-CLB) was synthesized by Bacillus tropicus using tanning industry solid waste, animal fleshing by de novo substrate-dependent synthesis pathway. Interestingly, the HR-CLB anchored functionalized carbon (HR-CLBAFC) demonstrated a high lignin sequestration capacity of 93.2 mg/g HR-CLBAFC at optimized time, 60 min; pH, 5; temperature, 45 °C; and mass of HR-CLBAFC, 1.0 g. The sequestration was confirmed by HR-SEM, UV–Vis., FT-IR, and WCA analyses. The isotherm studies revealed the involvement of Freundlich isotherm (regression coefficient, R2: 0.988) in regulating lignin sequestration onto HR-CLBAFC with a Freundlich constant (Kf) of 16.46 ((mg/g)(L/mg)1/n). Moreover, the kinetics studies divulged the contribution of the pseudo-second-order kinetic model (R2: 0.992) in regulating the dynamic mechanism of lignin sequestration onto HR-CLBAFC with a rate constant (k2) of 0.00022 g/mg min. Additionally, the thermodynamics studies discovered a positive Gibbs free energy (ΔG: +170 kJ/mol) and entropy (ΔS°: +130 kJ/mol), indicating the involvement of chemical interaction during the sequestration. Furthermore, the mechanistic study confirmed the role of an incomplete valence shell of nitrogen in histidine centers of HR-CLB in regulating electrostatic interaction with lignin molecules during the sequestration process. Subsequently, the HR-CLBAFC applied for lignin sequestration from the real-time PPI effluent demonstrated an outstanding sequestration efficiency (>99.4%), confirming the unequivocal potential of the HR-CLBAFC matrix in lignin sequestration from real-time PPI effluent.

Synergistic C2H2 Binding Sites in Hydrogen-Bonded Supramolecular Framework for One-Step C2H4 Purification from Ternary C2 Mixture.

Purification of C2H4 from the ternary C2 hydrocarbon mixture in one step is of critical significance but still extremely challenging according to its intermediate physical properties between C2H6 and C2H2. Hydrogen-bonded organic frameworks (HOFs) stabilized by supramolecular interactions are emerging as a new kind of adsorbents that facilitate green separation. However, it remains a problem to efficiently realize the one-step C2H4 purification from C2H6/C2H4/C2H2 mixture because of the low C2H2/C2H4 selectivity. We herein report a robust microporous HOF (termed as HOF-TDCPB) with dense O atoms and aromatic rings distributed on the pore surface which provide C2H6 and C2H2 preferred environment simultaneously. Dynamic breakthrough experiments indicate that HOF-TDCPB can not only obtain high-purity C2H4 from binary C2 mixture, but also firstly realize one-step C2H4 purification from ternary C2H6/C2H4/C2H2 mixture, with the C2H4 productivity of 3.2 L/kg (>99.999 %) for one breakthrough cycle. Furthermore, HOF-TDCPB displays outstanding stability in air, organic solvents and water, which endow it excellent cycle performance even under high-humidity conditions. Theoretical calculations indicate that multiple O sites on pore channels can create synergistic binding sites for C2H2, thus affording overall stronger multipoint interactions.

Synergistic C2H2 Binding Sites in Hydrogen‐Bonded Supramolecular Framework for One‐Step C2H4 Purification from Ternary C2 Mixture

AbstractPurification of C2H4 from the ternary C2 hydrocarbon mixture in one step is of critical significance but still extremely challenging according to its intermediate physical properties between C2H6 and C2H2. Hydrogen‐bonded organic frameworks (HOFs) stabilized by supramolecular interactions are emerging as a new kind of adsorbents that facilitate green separation. However, it remains a problem to efficiently realize the one‐step C2H4 purification from C2H6/C2H4/C2H2 mixture because of the low C2H2/C2H4 selectivity. We herein report a robust microporous HOF (termed as HOF‐TDCPB) with dense O atoms and aromatic rings distributed on the pore surface which provide C2H6 and C2H2 preferred environment simultaneously. Dynamic breakthrough experiments indicate that HOF‐TDCPB can not only obtain high‐purity C2H4 from binary C2 mixture, but also firstly realize one‐step C2H4 purification from ternary C2H6/C2H4/C2H2 mixture, with the C2H4 productivity of 3.2 L/kg (&gt;99.999 %) for one breakthrough cycle. Furthermore, HOF‐TDCPB displays outstanding stability in air, organic solvents and water, which endow it excellent cycle performance even under high‐humidity conditions. Theoretical calculations indicate that multiple O sites on pore channels can create synergistic binding sites for C2H2, thus affording overall stronger multipoint interactions.

Neutralisation resistance of SARS-CoV-2 spike-variants is primarily mediated by synergistic receptor binding domain substitutions

ABSTRACT The evolution of SARS-CoV-2 has led to the emergence of numerous variants of concern (VOCs), marked by changes in the viral spike glycoprotein, the primary target for neutralising antibody (nAb) responses. Emerging VOCs, particularly omicron sub-lineages, show resistance to nAbs induced by prior infection or vaccination. The precise spike protein changes contributing to this resistance remain unclear in infectious cell culture systems. In the present study, a large panel of infectious SARS-CoV-2 mutant viruses, each with spike protein changes found in VOCs, including omicron JN.1 and its derivatives KP.2 and KP.3, was generated using a reverse genetic system. The susceptibility of these viruses to antibody neutralisation was measured using plasma from convalescent and vaccinated individuals. Synergistic roles of combined substitutions in the spike receptor binding domain (RBD) were observed in neutralisation resistance. However, recombinant viruses with the entire spike protein from a specific VOC showed enhanced resistance, indicating that changes outside the RBD are also significant. In silico analyses of spike antibody epitopes suggested that changes in neutralisation could be due to altered antibody binding affinities. Assessing ACE2 usage for entry through anti-ACE2 antibody blocking and ACE2 siRNA revealed that omicron BA.2.86 and JN.1 mutant viruses were less dependent on ACE2 for entry. However, surface plasmon resonance analysis showed increased affinity for ACE2 for both BA.2.86 and JN.1 compared to the ancestral spike. This detailed analysis of specific changes in the SARS-CoV-2 spike enhances understanding of coronavirus evolution, particularly regarding neutralising antibody evasion and ACE2 entry receptor dependence.

The Chemistry of Metal–Organic Frameworks for Multicomponent Gas Separation

AbstractAdsorbents‐based gas separation technologies are regarded as the potential energy‐efficient alternatives towards current thermal‐driven methods, and the study on multi‐component gas separation is essential to deepen our understanding of the adsorbents for practical use. Relative to the ideal two‐component mixtures, both the adsorption behavior and separation mechanisms are obviously more complex in multiple gas mixtures due to their close or even overlapped sizes and properties. The emergence of metal–organic frameworks with controllable pore size and pore chemistry provides the platform for the tailor‐made pore structure to satisfy the harsh requirements of multi‐component gas separation. This minireview highlights the recent advance of multi‐component gas separation using metal–organic frameworks, including multiple impurities removal and selective molecular capture. Combining with the typical cases of hydrocarbon separations (C2, C4, and C8), the detailed discussion about the developed strategies (e.g. self‐adaptive binding sites, multiple binding spaces, synergistic binding sites, synergistic sorbent separation technology, gate‐opening effect, size and thermodynamic combine effect) that are adaptive to different scenarios would be provided. The review will conclude with our perspective on the existing barriers and the future direction of this topic.

Modelling the mechanisms of antibody mixtures in viral infections: the cases of sequential homologous and heterologous dengue infections.

Antibodies play an essential role in the immune response to viral infections, vaccination or antibody therapy. Nevertheless, they can be either protective or harmful during the immune response. Moreover, competition or cooperation between mixed antibodies can enhance or reduce this protective or harmful effect. Using the laws of chemical reactions, we propose a new approach to modelling the antigen-antibody complex activity. The resulting expression covers not only purely competitive or purely independent binding but also synergistic binding which, depending on the antibodies, can promote either neutralization or enhancement of viral activity. We then integrate this expression of viral activity in a within-host model and investigate the existence of steady-states and their asymptotic stability. We complete our study with numerical simulations to illustrate different scenarios: firstly, where both antibodies are neutralizing and secondly, where one antibody is neutralizing and the other enhancing. The results indicate that efficient viral neutralization is associated with purely independent antibody binding, whereas strong viral activity enhancement is expected in the case of purely competitive antibody binding. Finally, data collected during a secondary dengue infection were used to validate the model. The dataset includes sequential measurements of virus and antibody titres during viremia in patients. Data fitting shows that the two antibodies are in strong competition, as the synergistic binding is low. This contributes to the high levels of virus titres and may explain the antibody-dependent enhancement phenomenon. Besides, the mortality of infected cells is almost twice as high as that of susceptible cells, and the heterogeneity of viral kinetics in patients is associated with variability in antibody responses between individuals. Other applications of the model may be considered, such as the efficacy of vaccines and antibody-based therapies.

Achieving Record C2H2 Packing Density for Highly Efficient C2H2/C2H4 Separation with a Metal–Organic Framework Prepared by a Scalable Synthesis in Water

AbstractAdsorptive C2H2/C2H4 separation using metal–organic frameworks (MOFs) has emerged as a promising technology for the removal of C2H2 (acetylene) impurity (1 %) from C2H4 (ethylene). The practical application of these materials involves the optimization of separation performance as well as development of scalable and green production protocols. Herein, we report the efficient C2H2/C2H4 separation in a MOF, Cu(OH)INA (INA: isonicotinate) which achieves a record C2H2 packing density of 351 mg cm−3 at 0.01 bar through high affinity towards C2H2. DFT (density functional theory) calculations reveal the synergistic binding mechanism through pore confinement and the oxygen sites in pore wall. The weakly basic nature of binding sites leads to a relatively low heat of adsorption (Qst) of approximately 36 kJ/mol, which is beneficial for material regeneration and thermal management. Furthermore, a scalable and environmentally friendly synthesis protocol with a high space‐time yield of 544 kg m−3 day−1 has been developed without using any modulating agents. This material also demonstrates enduring separation performance for multiple cycles, maintaining its efficacy after exposure to water or air for three months.

Achieving Record C2H2 Packing Density for Highly Efficient C2H2/C2H4 Separation with a Metal-Organic Framework Prepared by a Scalable Synthesis in Water.

Adsorptive C2H2/C2H4 separation using metal-organic frameworks (MOFs) has emerged as a promising technology for the removal of C2H2 (acetylene) impurity (1%) from C2H4 (ethylene). The practical application of these materials involves the optimization of separation performance as well as development of scalable and green production protocols.Herein, we report the efficient C2H2/C2H4 separation in a MOF, Cu(OH)INA (INA: isonicotinate) which achieves a record C2H2 packing density of 351 mg cm-3 at 0.01 bar through high affinity towards C2H2. DFT (density functional theory) calculations reveal the synergistic binding mechanism through pore confinement and the oxygen sites in pore wall.The weakly basic nature of binding sites leads to a relatively low heat of adsorption (Qst) of approximately 36 kJ/mol, which is beneficial for material regeneration and thermal management. Furthermore, a scalable and environmentally friendly synthesis protocol with a high space-time yield of 544 kg m-3 day-1 has been developed without using any modulating agents. This material also demonstrates enduring separation performance for multiple cycles, maintaining its efficacy after exposure to water or air for three months.

The Chemistry of Metal-Organic Frameworks for Multicomponent Gas Separation.

Adsorbents-based gas separation technologies are regarded as the potential energy-efficient alternatives towards current thermal-driven methods, and the study on multi-component gas separation is essential to deepen our understanding of the adsorbents for practical use. Relative to the ideal two-component mixtures, both the adsorption behavior and separation mechanisms are obviously more complex in multiple gas mixtures due to their close or even overlapped sizes and properties. The emergence of metal-organic frameworks with controllable pore size and pore chemistry provides the platform for the tailor-made pore structure to satisfy the harsh requirements of multi-component gas separation. This minireview highlights the recent advance of multi-component gas separation using metal-organic frameworks, including multiple impurities removal and selective molecular capture. Combining with the typical cases of hydrocarbon separations (C2, C4, and C8), the detailed discussion about the developed strategies (e.g. self-adaptive binding sites, multiple binding spaces, synergistic binding sites, synergistic sorbent separation technology, gate-opening effect, size and thermodynamic combine effect) that are adaptive to different scenarios would be provided. The review will conclude with our perspective on the existing barriers and the future direction of this topic.

The αC-β4 loop controls the allosteric cooperativity between nucleotide and substrate in the catalytic subunit of protein kinase A

Allosteric cooperativity between ATP and substrates is a prominent characteristic of the cAMP-dependent catalytic subunit of protein kinase A (PKA-C). This long-range synergistic action is involved in substrate recognition and fidelity, and it may also regulate PKA’s association with regulatory subunits and other binding partners. To date, a complete understanding of this intramolecular mechanism is still lacking. Here, we integrated NMR(Nuclear Magnetic Resonance)-restrained molecular dynamics simulations and a Markov State Model to characterize the free energy landscape and conformational transitions of PKA-C. We found that the apoenzyme populates a broad free energy basin featuring a conformational ensemble of the active state of PKA-C (ground state) and other basins with lower populations (excited states). The first excited state corresponds to a previously characterized inactive state of PKA-C with the αC helix swinging outward. The second excited state displays a disrupted hydrophobic packing around the regulatory (R) spine, with a flipped configuration of the F100 and F102 residues at the αC-β4 loop. We validated the second excited state by analyzing the F100A mutant of PKA-C, assessing its structural response to ATP and substrate binding. While PKA-CF100A preserves its catalytic efficiency with Kemptide, this mutation rearranges the αC-β4 loop conformation, interrupting the coupling of the two lobes and abolishing the allosteric binding cooperativity. The highly conserved αC-β4 loop emerges as a pivotal element to control the synergistic binding of nucleotide and substrate, explaining how mutations or insertions near or within this motif affect the function and drug sensitivity in homologous kinases.

The αC-β4 loop controls the allosteric cooperativity between nucleotide and substrate in the catalytic subunit of protein kinase A.

Allosteric cooperativity between ATP and substrates is a prominent characteristic of the cAMP-dependent catalytic subunit of protein kinase A (PKA-C). This long-range synergistic action is involved in substrate recognition and fidelity, and it may also regulate PKA's association with regulatory subunits and other binding partners. To date, a complete understanding of this intramolecular mechanism is still lacking. Here, we integrated NMR(Nuclear Magnetic Resonance)-restrained molecular dynamics simulations and a Markov State Model to characterize the free energy landscape and conformational transitions of PKA-C. We found that the apoenzyme populates a broad free energy basin featuring a conformational ensemble of the active state of PKA-C (ground state) and other basins with lower populations (excited states). The first excited state corresponds to a previously characterized inactive state of PKA-C with the αC helix swinging outward. The second excited state displays a disrupted hydrophobic packing around the regulatory (R) spine, with a flipped configuration of the F100 and F102 residues at the αC-β4 loop. We validated the second excited state by analyzing the F100A mutant of PKA-C, assessing its structural response to ATP and substrate binding. While PKA-CF100A preserves its catalytic efficiency with Kemptide, this mutation rearranges the αC-β4 loop conformation, interrupting the coupling of the two lobes and abolishing the allosteric binding cooperativity. The highly conserved αC-β4 loop emerges as a pivotal element to control the synergistic binding of nucleotide and substrate, explaining how mutations or insertions near or within this motif affect the function and drug sensitivity in homologous kinases.

Deep eutectic solvent-functionalized amorphous UiO-66 for efficient extraction and ultrasensitive analysis of perfluoroalkyl substances in infant milk powder

In this study, a convenient and effective method for determination of perfluoroalkyl substances (PFASs) in infant formula was developed based on a novel dispersive solid-phase extraction using deep eutectic solvent-functionalized amorphous UiO-66 (DES/aUiO-66) as sorbent. The synthesis of materials could be achieved without the use of complex and environmentally unfriendly procedures. Parameters were systematically investigated to establish a simple, fast, and efficient green pretreatment method. The method demonstrated high sensitivity, good precision, a detection limit of 0.330–0.529 ng·kg−1, and low matrix effects (< 12.8%). The mechanism for this material was elucidated by ab initio molecular dynamics (AIMD) simulations and quantum chemistry calculations. The presence of massive pore structures and collectively synergistic binding sites facilitated affinity adsorption toward PFASs. Finally, this method was applied to the monitoring of PFASs in 10 actual milk powder samples. This groundbreaking approach opens new possibilities for the advancement of analytical techniques and food safety monitoring.

Assembly process of locust bean gum and xanthan gum for synergistic gelling revealed by atomic force microscopy

Synergistic interaction gels (SIGs) have become attractive in food industry due to their ability to modify rheology features, realize safe swallowing and apply as fat simulants. Locust bean gum (LBG) and xanthan give rise to SIG, however, their assembly process remain elusive. This work demonstrated that, in xanthan-rich system, xanthan chains transformed into helical structure and aggregated into thick bundles upon cooling. Subsequently they bound with LBG clusters, constructing a xanthan-like 3D gel network. However, in LBG-rich system, LBG chains gradually dissociated from clusters and associated into helical structure during cooling (“dissociation-association” process), forming an LBG-like “sea-island” structure. With further cooling, LBG continued to undergo “dissociation-association” process, along with specifically binding by xanthan chains (helical structure or thick bundles), generating thick grid contour lines and larger sparse gel network. The enthalpy change values indicated that with the decrease of xanthan content, synergistic binding extent was increased and then decreased, reaching the maximum at LBG: xanthan ratio of 7:3. This was responsible for the increment of G′, gel hardness, and capacity to accumulate energy for the weak shear-induced structure for LBG/xanthan SIGs. This study serves to facilitate the design and production of SIGs with the requisite performance characteristics.

Sea Anemone-Inspired Conducting Polymer Sensing Platform for Integrated Detection of Tumor Protein Marker and Circulating Tumor Cell.

Combining the detection of tumor protein markers with the capture of circulating tumor cells (CTCs) represents an ultra-promising approach for early tumor detection. However, current methodologies have not yet achieved the necessary low detection limits and efficient capture. Here, a novel polypyrrole nanotentacles sensing platform featuring anemone-like structures capable of simultaneously detecting protein biomarkers and capturing CTCs is introduced. The incorporation of nanotentacles significantly enhances the electrode surface area, providing abundant active sites for antibody binding. This enhancement allows detecting nucleus matrix protein22 and bladder tumor antigen with 2.39 and 3.12 pg mL-1 detection limit, respectively. Furthermore, the developed sensing platform effectively captures MCF-7 cells in blood samples with a detection limit of fewer than 10 cells mL-1, attributed to the synergistic multivalent binding facilitated by the specific recognition antibodies and the positive charge on the nanotentacles surface. This sensing platform demonstrates excellent detection capabilities and outstanding capture efficiency, offering a simple, accurate, and efficient strategy for early tumor detection.

Ratiometric Fluorescence Aptasensor of Allergen Protein Based on Multivalent Aptamer-Encoded DNA Flowers as Fluorescence Resonance Energy Transfer Platform.

Life-threatening allergic reactions to food allergens, particularly peanut protein Ara h1, are a growing public health concern affecting millions of people worldwide. Thus, accurate and rapid detection is necessary for allergen labeling and dietary guidance and ultimately preventing allergic incidents. Herein, we present a novel ratiometric fluorescence aptasensor based on multivalent aptamer-encoded DNA flowers (Mul-DNFs) for the high-stability and sensitive detection of allergen Ara h1. The flower-shaped Mul-DNFs were spontaneously packaged using ultralong polymeric DNA amplicons driven by a rolling circle amplification reaction, which contains a large number of Ara h1 specific recognition units and has excellent binding properties. Furthermore, dual-color fluorescence-labeled Mul-DNFs probes were developed by hybridizing them with Cy3- and Cy5-labeled complementary DNA (cDNA) to serve as a ratiometric fluorescence aptasensor platform based on fluorescence resonance energy transfer. Benefiting from the combined merits of the extraordinary synergistic multivalent binding ability of Mul-DNFs, the excellent specificity of the aptamer, and the sensitivity of the ratiometric sensor to avoid exogenous interference. The developed ratiometric aptasensor showed excellent linearity (0.05-2000 ng mL-1) with a limit of detection of 0.02 ng mL-1. Additionally, the developed ratiometric fluorescence aptasensor was utilized for quantifying the presence of Ara h1 in milk, infant milk powder, cookies, bread, and chocolate with recoveries of 95.7-106.3%. The proposed ratiometric aptasensor is expected to be a prospective universal aptasensor platform for the rapid, sensitive, and accurate determination of food and environmental hazards.

Biochemical and structural characterization of chlorhexidine as an ATP-assisted inhibitor against type 1 methionyl-tRNA synthetase from Gram-positive bacteria

Methionyl-tRNA synthetase (MetRS) catalyzes the attachment of l-methionine (l-Met) to tRNAMet to generate methionyl-tRNAMet, an essential substrate for protein translation within ribosome. Owing to its indispensable biological function and the structural discrepancies with human counterpart, bacterial MetRS is considered an ideal target for developing antibacterials. Herein, chlorhexidine (CHX) was identified as a potent binder of Staphylococcus aureus MetRS (SaMetRS) through an ATP-aided affinity screening. The co-crystal structure showed that CHX simultaneously occupies the enlarged l-Met pocket (EMP) and the auxiliary pocket (AP) of SaMetRS with its two chlorophenyl groups, while its central hexyl linker swings upwards to interact with some conserved hydrophobic residues. ATP adopts alternative conformations in the active site cavity, and forms ionic bonds and water-mediated hydrogen bonds with CHX. Consistent with this synergistic binding mode, ATP concentration-dependently enhanced the binding affinity of CHX to SaMetRS from 10.2 μM (no ATP) to 0.45 μM (1 mM ATP). While it selectively inhibited two representative type 1 MetRSs from S. aureus and Enterococcus faecalis, CHX did not show significant interactions with three tested type 2 MetRSs, including human cytoplasmic MetRS, in the enzyme inhibition and biophysical binding assays, probably due to the conformational differences between two types of MetRSs at their EMP and AP. Our findings on CHX may inspire the design of MetRS-directed antimicrobials in future.

Synergistic Binding of SARS-CoV-2 to ACE2 and Gangliosides in Native Lipid Membranes.

Viruses utilize cell surface glycans and plasma membrane receptors to attain an adequate attachment strength for initiating cellular entry. We show that SARS-CoV-2 particles bind to endogenous ACE2 receptors and added sialylated gangliosides in near-native membranes. This was explored using supported membrane bilayers (SMBs) that were formed using plasma membrane vesicles having endogenous ACE2 and GD1a gangliosides reconstituted in lipid vesicles. The virus binding rate to the SMBs is influenced by GD1a and inhibition of the ganglioside reduces the extent of virus binding to the membrane receptors. Using combinations of inhibition assays, we confirm that added GD1a in lipid membranes increases the availability of the endogenous ACE2 receptor and results in the synergistic binding of SARS-CoV-2 to the membrane receptors in SMBs.

In Silico Investigations on the Synergistic Binding Mechanism of Functional Compounds with Beta-Lactoglobulin.

Piceatannol (PIC) and epigallocatechin gallate (EGCG) are polyphenolic compounds with applications in the treatment of various diseases such as cancer, but their stability is poor. β-lactoglobulin (β-LG) is a natural carrier that provides a protective effect to small molecule compounds and thus improves their stability. To elucidate the mechanism of action of EGCG, PIC, and palmitate (PLM) in binding to β-LG individually and jointly, this study applied molecular docking and molecular dynamics simulations combined with in-depth analyses including noncovalent interaction (NCI) and binding free energy to investigate the binding characteristics between β-LG and compounds of PIC, EGCG, and PLM. Simulations on the binary complexes of β-LG + PIC, β-LG + EGCG, and β-LG + PLM and ternary complexes of (β-LG + PLM) + PIC, (β-LG + PLM) + EGCG, β-LG + PIC) + EGCG, and (β-LG + EGCG) + PIC were performed for comparison and characterizing the interactions between binding compounds. The results demonstrated that the co-bound PIC and EGCG showed non-beneficial effects on each other. However, the centrally located PLM was revealed to be able to adjust the binding conformation of PIC, which led to the increase in binding affinity with β-LG, thus showing a synergistic effect on the co-bound PIC. The current study of β-LG co-encapsulated PLM and PIC provides a theoretical basis and research suggestions for improving the stability of polyphenols.

Evaluation of 177Lu-Labeled Pertuzumab F(ab')2 Fragments for HER2-Positive Cancer Targeting: A Comparative In Vitro and In Vivo Study.

Background: Radiolabeled antibody fragments present a promising opportunity as theranostic agents, offering distinct advantages over whole antibodies. In this study, the authors investigate the potential of [177Lu]Lu-DTPA-F(ab')2-pertuzumab as a theranostic agent for precise targeting of human epidermal growth factor receptor 2 (HER2)-positive cancers. Additionally, the authors aim to quantitatively assess the binding synergism in the presence of cold trastuzumab. Materials and Methods: F(ab')2-pertuzumab was prepared by pepsin digestion and conjugated with a bifunctional chelator. The immunoconjugate was radiolabeled with 177Lu and characterized by chromatography techniques. Binding parameters (affinity, specificity, and immunoreactivity) and cellular binding enhancement studies were evaluated in HER2-overexpressing and triple-negative cell lines. The in vivo enhancement in tumor uptake of the radiolabeled immunoformulation was assessed in severe combined immunodeficient (SCID) mice bearing tumors, both in the presence and absence of unlabeled trastuzumab. Results: The formulation of [177Lu]Lu-DTPA-F(ab')2-pertuzumab could be prepared in high yields and with consistent radiochemical purity, ensuring reproducibility. Comprehensive in vitro and in vivo evaluation studies confirmed high specificity and immunoreactivity of the formulation toward HER2 receptors. Binding synergism of radiolabeled pertuzumab fragments in the presence of trastuzumab to HER2 receptors was observed. Conclusions: The radioformulation of [177Lu]Lu-DTPA-F(ab')2-pertuzumab holds great promise as a targeted approach for addressing HER2-positive cancers. A potentially effective strategy to amplify therapeutic efficacy involves dual epitope targeting by combining radiolabeled pertuzumab with cold trastuzumab.