Fluorescence Spectroscopic Studies Research Articles

Examining Terpyridine Ligand Binding Interactions with Cobalt and Aluminium: Synthesis, ADME Assessment, Reversibility, and DFT Analysis.

This article emphasizes the influence of pyridine ring substitutions in 2,2':6',2″-terpyridine unit, allowing for precise adjustment of ligand properties. This study explores terpyridine-based molecular systems, with its unique coordination properties assessed against a range of competing metal ions, highlighting the specific affinity of the terpyridine ligand towards aluminium (Al) and cobalt (Co) detection in Acetonitrile-water (ACN-H2O) mixed solvent (80:20). The terpyridine-based probe's structural component is meticulously designed and detailed investigated to understand their influence on sensing performance. Synthesised probes are characterised using NMR, IR, UV-Vis spectroscopy, and mass spectrometry. Such modifications present ample opportunities to customise the attributes and applications of resultant metal complexes. The interaction between the terpyridine-based probes and target metal ions is investigated through various experimental methods, including fluorescence spectroscopy and UV studies along with unassisted discernment of Cobalt through Naked-Eye. Observation turns out that the limit of detection is 4.4 × 10-8mol/L for cobalt and 4 × 10-7mol/L for aluminium and coordination features Showing the binding stoichiometry to be 1:1 for R1. ADME Studies have been performed to analyse pharmacokinetic and biological actions. DFT calculations were performed to investigate the molecular probe's coordination features and its corresponding metal complex.

Investigating the binding of fluorescent probes to a trypanosomal-tRNA synthetase: A fluorescence spectroscopic and molecular dynamics study.

Given the high prevalence of Chagas disease in the Americas, we targeted the unique arginyl-tRNA synthetase of its causative agent Trypanosoma cruzi. Among their many possible uses, naphthalene-derived fluorescent ligands, such as ANS and bis-ANS, may be employed in pharmacokinetic research. Although ANS and bis-ANS have become prominent fluorescent probes for protein characterization, the structural and spectroscopic characteristics of protein-ANS/bis-ANS complexes remain largely unknown. Both fluorescent dyes bind to either the folded or partially folded hydrophobic regions of proteins. Additionally, they serve to identify molten globule-like intermediates. These probes have been used to study the folding problems of protein structures and the mechanisms of protein-protein interactions. ANS and bis-ANS exhibited significant enhancement and blue shift in their emission spectra upon binding to TcArgRS, the primary enzyme responsible for attaching l-arginine to its corresponding tRNA. Through fluorescence spectroscopy and computational studies, we concluded that bis-ANS binds more tightly to TcArgRS and that ATP affects bis-ANS fluorescence signal. Thus, these probes are useful resources for studying the intricate intermolecular relationships between proteins in terms of their structure, function, and mechanism. Our study provides a framework for identifying the hydrophobic regions present in TcArgRS. The utilization of hydrophobic patches on proteins for drug targeting is noteworthy because they can assist in identifying regions on the surface of proteins that are likely to interact with ligands. These patches help identify hotspot residues that play a vital role in determining binding affinity. Drugs are mainly small and hydrophobic in nature, and they target protein surfaces which have complementary properties. In this study, we elucidated the potential of TcArgRS as a target for combating trypanosomal diseases and extending life expectancy.

Molecular Interactions of the Antimicrobial Peptide Tritrpticin with Mixed Nanoaggregates: A Fluorescence Spectroscopy Study.

Tritrpticin (TRP3) is a peptide belonging to the cathelicidin family and has a broad spectrum of antimicrobial activity. However, this class of biomolecules can be easily degraded in the body, making it necessary to use an efficient transport system. The ability to form stable nanostructures from the interaction of glycyrrhizin saponin with the pluronic polymer F127 was demonstrated, forming mixed biopolymeric micelles, highly promising as drug carriers. The present work sought to understand the physicochemical interaction of the antimicrobial peptide TRP3 with the mixed polymeric micelle made from pluronic F127 and the saponin glycyrrhizin. The interaction of tritrpticin with mixed nanostructured micelles was evaluated through fluorescence spectroscopy and fluorescence quenching with acrylamide. The experiments were performed at room temperature (25 ± 1°C), adopting an excitation wavelength set to 280 nm and emission between 300 and 500 nm, with a slit of 5 nm. The interaction of the cationic peptide tritrpticin with the mixed biopolymeric micelles was observed through the blue shift of the fluorescence emission to shorter wavelengths, proving the change of tryptophan to a more hydrophobic environment. Through the fluorescence suppression technique, it was possible to indicate the location of the peptide in the mixed micelles, proving tritrpticin to be partially inserted inside them. It was concluded that tritrpticin interacted with mixed nanostructured micelles, forming a promising system for biotechnological applications.

Substituent effect in protein binding, optical, electrochemical, and antimicrobial properties of dipyrazinylpyridine ligands

A series of 2,6-di(pyrazine-2-yl)pyridine (dppy) ligands 1–4 of varying substituents of different electronic nature (-NMe2, -OMe,–Me, and -Cl) in the 4-position of the pyridine moiety has been designed and synthesized to study the binding behavior of the dppy ligands towards Bovine Serum Albumin (BSA), a low-cost serum albumin protein. The interaction between ligands 1–4 and BSA has been studied using UV-Visible and fluorescence spectroscopy and molecular docking studies. The fluorescence of BSA was found to be quenched in the presence of all the ligands 1–4, in which ligand 1, having the most electron donating group NMe2, exhibits the maximum binding affinity towards BSA. The interaction between ligands 1–4 and BSA was found to be static and spontaneous in nature. Further, the effect of substituents on the photophysical, thermal, and electrochemical properties of the dppy ligands has also been studied. Structure optimization and theoretical studies have been conducted to acquire a deeper understanding of the ligands’ nature. The trend of the energy gaps between the HOMO and the LUMO of the synthesized ligands 1–4, calculated from the electrochemical analysis, has been reflected in the theoretical observations. Moreover, the ligands were also tested against different bacterial and fungal strains, and ligands containing electron-donating–NMe2 and–OMe groups were quite active in both bacterial and fungal studies. The ligand 4, having the–CH3 group, showed moderate activity against fungal strains.

Structural modification of lipid membranes by polyphenols: A fluorescence spectroscopy study.

The present study investigates the molecular mechanisms of polyphenol-lipid interactions and their impact on membrane properties. Using pyrene and DPH as reporter molecules, we examined the impact of quercetin, curcumin, gallic, and salicylic acids on membranes composed of phosphatidylcholine (PC) and its mixtures with phosphatidylglycerol (PG), cardiolipin (CL), and cholesterol (Chol). Quercetin was found to increase the lipid order without affecting the lipid bilayer free volume, indicating interactions near the membrane surface. In turn, curcumin exhibited more complex effects, reducing free volume in PC but increasing it in PG vesicles, reflecting its amphiphilic structure and variable penetration depth. Gallic and salicylic acids selectively increased free volume at the membrane core without influencing lipid order at the upper regions of lipid bilayer. The results obtained demonstrate that polyphenol structure and lipid composition dictate the resultant pattern of polyphenol-membranes interactions, which may have implications for drug delivery and nutraceutical design.

The Calcium-Dependent Antibiotics: Structure-Activity Relationships and Determination of Their Lipid Target.

The calcium-dependent antibiotics (CDAs) are a group of seven closely related membrane-active cyclic lipopeptide antibiotics (cLPAs) first isolated in the early 1980s from the fermentation broth of Streptomyces coelicolor. Their target was unknown, and the mechanism of action is uncertain. Herein, we report new routes for the synthesis of CDA4b and its analogues, explore the structure-activity relationships at its lipid tail and at positions 3, 9, and 11, and determine the CDAs' lipid target. A CDA4b analogue in which the epoxide group in CDA's 6-carbon lipid was replaced with a cyclopropyl group was 4-fold more active than CDA4b which suggests that the epoxide group is not acting as an electrophile to form a covalent bond with CDA4b's target. The activity of this cyclopropyl analogue was significantly increased by extending the length of the lipid to 10 carbons. Studies with analogues in which d-HOAsn9 is replaced with d-Asn9 or d-Ser9 reveal that the hydroxy group of the d-HOAsn9 residue is not crucial for CDAs' activity, while the amide moiety is important for activity. The l-Trp residue at position 11 could be replaced with l-kynurenine (l-Kyn) without significant loss of activity, while replacing the d-Trp residue at position 3 with d-Kyn resulted in a significant loss of activity. MIC values determined in the presence and absence of exogenous phospholipids and fluorescence spectroscopy studies using natural CDAs and CDA4b analogues containing Kyn and model membranes revealed that the CDAs' primary lipid target is cardiolipin, a target that is unique among the broader class of known calcium-dependent antibiotics.

Naphthalene Diimide-Embedded Donor-Acceptor Carbon Nanohoops: Photophysical, Photoconductive, and Charge Transport Properties.

Designing the architecture of donor-acceptor (D-A) pairs is an effective strategy to tailor the electronic structure of conjugated macrocycles for optoelectronic devices. Herein, we present the synthesis of three D-A nanohoops NDI-[n]CPP (n = 7, 8, 9) containing a naphthalene diimide (NDI) unit as an acceptor and [n]cycloparaphenylenes ([n]CPPs) moieties as donors. The D-A characteristics of NDI-[7-9]CPPs were substantiated through absorption and fluorescence spectroscopic studies, electrochemical investigations, and computational analysis. The device investigations demonstrated that the D-A nanohoops NDI-[7-9]CPPs can serve as the photoconductive layer and demonstrate a significant generation of photocurrent with a fast response upon exposure to light. The magnitude of photocurrent shows high dependence on the size of their rings, with an increasing tendency as the ring size decreases. The generation of photocurrent in free acceptor-based CPP has rarely been reported in the previous literature. Significantly, the C60 complexes of NDI-[7-9]CPPs exhibited a marked enhancement in photocurrent under identical conditions; in particular, the photocurrent of C60⊂NDI-[7]CPP is ca. 3.5 times greater than that of NDI-[7]CPP alone. Furthermore, the potential applications of NDI-[7-9]CPPs in electron- and hole-transport devices have also been explored, revealing the clear evidence of their bipolar behavior as an active charge transport layer.

Molecular insights into the aspartate protease Plasmepsin II activity inhibition by fluoroquinolones: A pathway to antimalarial drug development

Plasmepsin II (PlmII) belongs to the aspartate proteases and is involved in hemoglobin degradation in Plasmodium falciparum. Due to its critical role in the survival of the Plasmodium, PlmII is considered as a potent drug target for antimalarial therapy. We have done recombinant protein production of pro-plasmepsin II (Pro-plmII). Pro-PlmII was further activated to mature form (mPlmII) and its activity was confirmed by enzyme kinetics studies. The fluorescence spectroscopic and isothermal titration calorimetric studies show that fluoroquinolone-based antibiotic drugs norfloxacin, ciprofloxacin, and sparfloxacin bind with mPlmII. Molecular docking results show that only norfloxacin and ciprofloxacin are able to bind at the active site of mPlmII via hydrogen binding and hydrophobic interactions. Enzyme kinetics analysis reveals that norfloxacin and ciprofloxacin effectively inhibit mPlmII activity, while sparfloxacin does not exhibit any inhibitory effect on the enzyme's catalytic function. The two methyl groups on the 3rd and 5th carbon atoms of the piperazine ring make sparfloxacin unable to go inside mPlmII and bind at its active site. Overall, the results here suggested that fluoroquinolone-based antibiotic drugs norfloxacin, and ciprofloxacin, can be repurposed as antimalarial inhibitors targeting aspartic proteases. These findings contribute to pave the way for potential therapeutic interventions targeted at malaria.

Tau destabilization in a familial deletion mutant K280 accelerates its fibrillization and enhances the seeding effect.

Tauopathies cover a range of neurodegenerative diseases in which natively unfolded tau protein aggregates and spreads in the brain during disease progression. To gain insights into the mechanism of tau structure and spreading, here, we examined the biochemical and cellular properties of human full-length wild-type and familial mutant tau, ΔK280, with a deletion at lysine 280. Our results showed that both wild-type and mutant tau are predominantly monomeric by analytical ultracentrifugation. The mutant tau may lose intramolecular contacts and is significantly destabilized assessed by cross-linking mass spectrometry and urea denaturation. Moreover, the mutant tau displayed accelerated fibril formation compared to the wild-type tau. Upon cross-seeding, the wild-type tau was seeded more easily by wild-type seeds than mutant seeds showing that homotypic seeding is more efficient. The wild-type tau was successfully converted to fibrils with mutant signatures by mutant seeds. Live cell cross-correlation fluorescence spectroscopy studies indicated that wild-type tau forms trimeric species and the mutant tau forms a larger assembly and processes higher cell-to-cell transmission. Overall, these findings shed light on the fundamental mechanisms of tau structure/stability, aggregation, and seeding to facilitate future therapeutic development for tauopathies.

Versatile Benzophenone Derivatives: Broad Spectrum Antibiotics, Antioxidants, Anticancer Agents and Fe(III) Chemosensor

ABSTRACTBenzophenone is a versatile molecular scaffold that has been extensively explored in medicinal chemistry because of its propensity to exhibit a wide range of biological activities. This study represents a new azide (5) and triazole (6) compounds that were synthesized and well characterized by using FTIR, 1H and 13C NMR spectroscopy and mass spectrometry. UV‐vis and fluorescence spectroscopic studies identified the sensitivity of compound 6 towards Fe(III) with no substantial interference from other metal ions. LOD values for recognition of Fe(III) were found to be 7.94 × 10−5 and 3.67 × 10−7 M, respectively. The biological studies of the compounds (5 and 6) depicted the antibacterial activity against Bacillus subtilis, Staphylococcus aureus and Pseudomonas aeruginosa with the minimum inhibitory concentration range of antibiotics 0.12–6.2 mg/mL. Molecular docking experiments with various bacterial proteins demonstrated that compounds 5 and 6 possessed very low binding energies of −10.39 and −9.14 kcal mol−1 respectively. Both the compounds showed excellent cytotoxic activities against HeLa cells (cervical cell line). Further, the antioxidant quality of compound 6 has been analysed.

Designing of amiloride loaded citrate functionalized amorphous silica nanoparticles to investigate its genotoxic and cytotoxic potential

In the present work, silica-based nanocarrier for the anticancer drug, amiloride have been synthesized and characterized using various physicochemical techniques. The aim of this work emphasis on investigating the physicochemical properties and cytotoxic effects of citrate-functionalized amiloride loaded silica nanoparticles. Silica nanoparticles synthesis was carried out via condensation reaction, then coated by tris sodium citrate, followed by their functionalization using amiloride through EDC-NHS reaction. SEM and HR-XRD analysis indicated the formation of amorphous spherical silica nanoparticles. The existence of citrate coating was evident from FT-IR and TGA results, which were supported by DLS and zeta potential studies. The formation of amiloride conjugated citrate coated silica nanoparticles (SiNPs-Cit@Ami) was confirmed by the DLS, Zeta potential and UV-Visible spectroscopy. Size of SiNPs-Cit@Ami nanoparticles was found to be around 80nm using TEM. Additionally, these nanoparticles showed high loading efficiency and time-dependent release of amiloride. DNA binding studies were examined using UV–Visible, Fluorescence spectroscopic and Competitive fluorescence studies. The results indicate that SiNPs-Cit@Ami bind to Ct-DNA via minor groove binding mode. Furthermore, the cytotoxic effect of SiNPs-Cit@Ami on HepG2 cell lines was found to be higher than amiloride alone. Our findings suggest that SiNPs-Cit@Ami can be employed as a promising candidate for cancer mitigation.

Hydrates of N-((10-Chloroanthracen-9-yl)methyl)-3-(1H-imidazol-1-yl)propan-1-ammonium Cobalt(II), Copper(II), and Zinc(II) 2,6-Pyridinedicarboxylate: Reversible Crystallization.

In a quest to explore interconvertible assemblies of hydrates of cobalt(II), copper(II), and zinc(II) 2,6-pyridinedicarboxylate (26-pdc), complexes having cation of a chloro-substituted analogue N-{(10-chloroanthracen-9-yl)methyl}-3-(1H-imidazol-1-yl)propan-1-amine were investigated. In the case of cobalt and copper complexes, a crystallized stable hydrate and a less stable methanol hydrate were guided by concentration-dependent crystallizations. The unit-cells of the crystals of the methanol hydrates of the two cobalt and copper complexes each belong to the P1̅ space group but have different stoichiometries as well as large differences in packing. These hydrates could be reversibly crystallized in a predictable manner. The unit-cell volumes of the methanol hydrate of the cobalt complex were four-times smaller than that of the respective stable form (C2/c space group), whereas similar hydrates of the copper complex had a two-times smaller unit-cell volume than that of the stable form. The cations of the stable forms assembled together and formed zigzag ladder-like chains. The spaces present in between the assembled chains were filled with clusters of face to face stacked anions. The transformation to stable form required a bottom-up building process of the unit-cell starting from a smaller unit-cell of the less stable hydrates. Fluorescence spectroscopic studies showed the possibility of two forms of assemblies of the zinc-complex in solution, but crystallization had yielded only the stable form.

Microwave-assisted synthesis, characterization and molecular docking of two C2-symmetric Schiff bases as fluorescent dye for silk fibroin

Using non-cytotoxic fluorescent materials for staining Bombyx mori silk fibroin holds great promise for tissue engineering and regenerative medicine, as it could be used as a scaffold and monitor for cell growth. Here, we report the microwave-assisted synthesis of two fluorescent Schiff bases in short reaction time and good yields. Detailed characterization of the synthesized compounds using NMR (1H, 13C NMR, and 2D NMR experiments), HRMS (DART+), UV/Vis, fluorescence spectroscopy, and X-ray diffraction studies. The Schiff base molecular structures showed a non-planar arrangement with the C2 point group. Both compounds showed low cytotoxicity on colon carcinoma cells (Caco2, ATCCHTB-37) at different concentrations (1 to 5 μg/mL). Notably, Schiff bases exhibit good fluorescent staining of Bombyx mori silk fibroin by the immersion method and were analyzed by confocal microscopy. The fluorescent staining ability of the Schiff bases toward the silk fibroin was explored by molecular docking, where two predominant binding sites were identified, and H-bonding and other polar interactions were found to stabilize the binding modes of the compounds. From the remarkable findings and to the best of our knowledge, this is the first report on Schiff bases as a fluorescent dye of this biomaterial.

Unveiling the Ultrafast Excitation Energy Transfer in Tetraarylpyrrolo[3,2-b]pyrrole-BODIPY Dyads.

We have synthesized two dyads (dyad 1 and 2) comprising of tetraarylpyrrolo[3,2-b]pyrrole (TAPP) and BODIPY. In dyad 1, two BODIPYs are directly connected with TAPP moiety whereas in dyad 2, BODIPYs are connected through phenylethynyl linkers. TAPP is a blue energy donor which is easy to synthesize and functionalize as compared to other well-known blue energy donors like pyrene, perylene etc. This is the first report of using TAPP as an energy donor in BODIPY based dyad molecules. Complete quenching of TAPP fluorescence in the dyads suggests fast energy transfer from TAPP to BODIPY unit (ETE~99.9 %). Ultrafast fluorescence and transient absorption spectroscopic studies of dyad 1 showed TAPP to BODIPY energy transfer in 125 fs (kET=8.0×1012 s-1) which is one of the fastest energy transfer events in BODIPY based dyad reported so far. Whereas, in dyad 2, energy transfer is almost four times slower (480 fs, kET=2.1×1012 s-1). These results were rationalized by theoretical Förster formulations. This study shows that suitably matched optical properties of TAPP and BODIPY dyes along with their easy syntheses will be the key to develop highly efficient energy transfer systems in future for multiple applications.

Probing host guest inclusion complex and its applications by biophysical approach subsequently optimized by molecular docking

Herein, we explored the construction of a supramolecular encapsulated complex between Nile blue (NB) and p-sulfonatothiacalix[4]arene (TSC4X). The developed inclusion complex (NB-TSC4X) was established by fluorescence spectroscopy, TGA, FTIR, 1H NMR, and Docking studies. Benesi-Hildebrand calculation showed a linear plot that indicated a 1:1 stoichiometric ratio having a fairly high stability constant of 2720 M−1 in the solution phase. Docking analysis helps us to find out the optimized structure of the inclusion complex. Finally, the binding interaction of the inclusion complex with bovine serum albumin (BSA) was evaluated. In brief, this work uncloses a new strategy to enhance the performance of fluorescent dye.

Spectroscopic characterization of triazine based covalent organic framework tempted changes in the structure of hemoglobin

The present study aims to understand changes in the Hemoglobin (Hb) structure in the presence of a triazine based covalent organic framework (COF) through spectroscopic characterization. Covalent Organic Frameworks (COFs) due to their unique properties have been utilized in diverse fields including bio-applications. Utilization of COFs for conjugate formation with proteins will lead to the integration of biology and framework materials that can help in the development of bioconjugates for advanced bio-based applications such as diagnostics, therapeutics, and bioengineering. However, vital is to have a fundamental understanding of protein conformation in protein-COF conjugate. Herein, a triazine based COF has been synthesized via solvothermal method, termed TATF-COF which has been utilized for the formation of a conjugate with hemoglobin (Hb). Thereafter, studies have been performed to understand Hb structure in the presence of TATF-COF. Results from UV–vis, Fluorescence, and UV-CD spectroscopy studies revealed that in the presence of TATF-COF, there was a slight alteration in the Hb structure due to binding interactions between them and conjugate formation. Moreover, micrographs obtained from electron microscopy displayed formation of conjugate between Hb and TATF-COF result of binding interactions. DLS and zeta potential results also revealed conjugate formation due to binding interactions between TATF-COF and Hb. Thermal stability of Hb was also maintained as TATF-COF had insignificant effect on the Tm value of Hb. Overall, there was a slight alternation in the Hb native conformation due to binding interactions, however, TATF-COF was compatible with Hb as the protein’s native structure was well-preserved.

Synthesis, characterization, and application of pyrene-based chalcones AIEgens for cellular and intracellular activity

Herein, we described the design and synthesis of MAN-Br, MAN-I and MAN-OH, a novel pyrene-based chalcones with aggregation induced emission (AIE), DFT, and cellular imaging properties. MAN-Br, and MAN-I exhibited AIE in DMSO-water mixture and this was confirmed by fluorescence spectroscopy studies. These three compounds MAN-Br, MAN-I and MAN-OH was investigated by computational analysis in which their HUMO-LUMO, optimized geometry, molecular electrostatic potential (MEP) are included. The synthesized AIE compound MAN-Br, and MAN-I was found to be non-toxic and promising candidate for biological studies. Cell imaging experiments reveals that MAN-Br, and MAN-I can effectively enhance the signal-to-noise ratio of imaging by reducing the interference from background due to their impressive AIE characteristics. This work will provide guidance for the construction of biological applications on the base of AIE-active compounds, which offers multiple opportunities for multiple clinical applications under hypoxic conditions.

Biogenic synthesis of porous CuO nanoparticles: Synergistic effects in photocatalytic dye degradation and electrochemical energy storage applications

This study explores the biogenic synthesis of CuO nanoparticles functionalized with Solanum nigrum, using Acalypha indica leaf extract as a reducing agent. The biogenically synthesized CuO nanoparticles were comprehensively characterized by various analytical techniques, involves X-ray diffraction analysis (XRD), BET surface area analysis (BET), energy-dispersive X-ray spectroscopy (EDAX), X-ray photoelectron spectroscopy (XPS), UV–Visible spectral analysis (UV), Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy, electrochemical analysis, and linear sweep voltammetry studies. The XRD analysis revealed end centered monoclinic phase with a 10 nm average crystalline size. BET analysis showed a mesoporous structure with a surface area of 11.54 m2/g. XPS and EDAX confirmed the presence of Cu2+ and O2− ions. SEM and TEM images indicated spherical, and porous nanostructures. UV–Visible spectroscopy identified an active optical range of 508–518 nm (2.40–2.45 eV), suggesting potential photocatalytic activity. The photocatalytic degradation efficiencies of Methylene blue (98.8 %) and Rhodamine B (95 %) were achieved after 100 min of irradiation. Antimicrobial tests demonstrated effectiveness against Staphylococcus aureus, E. coli, Shigella flexneri, and Candida tropicalis. The nanoparticles exhibited notable cytotoxicity against colorectal cancer cells with IC50 values of 58.66 μg/ml. Additionally, a symmetric supercapacitor electrode using these nanoparticles achieved a specific capacitance of 375 Fg−1 at the current density of 1 Ag−1. This research underscores the versatile applications of biogenic CuO nanoparticles in photocatalysis, antimicrobial treatments, cancer therapy, and energy storage.

An insight for the interaction of Aceclofenac with hemoglobin using spectroscopic, electrochemical and in silico approaches

The interactions between protein and ligand are crucial to practically every biological function in the body, and investigations of these interactions are critical from the perspective of logical medication development. In this work, several biophysical methods like UV–Visible spectroscopy, fluorescence spectroscopy, and in-silico studies have been explored to examine the interaction between aceclofenac and haemoglobin. Spectrofluorimetric data confirmed the static nature of the protein quenching mechanism caused by the medication. ΔG for the formation of the complex via the interaction was found to be − 12.65 kJ/mol. Molecular docking showed a strong interaction between aceclofenac and hemoglobin with a binding energy of − 31.79 kJ/mol. Further, molecular dynamics simulations using Gromacs were run to investigate the stability of the protein with and without aceclofenac, and the ΔG for the formation of the complex (hemoglobin-aceclofenac) is − 105.09 kJ/mol with an error of 13.51 kJ/mol. Spectroscopic and in-silico calculations indicate the feasible binding of the aceclofenac with hemoglobin. Further, the interaction of haemoglobin with aceclofenac was studied by cyclic voltammetry.Graphical

Bioinorganic Chemistry Meets Microbiology: Copper(II) and Zinc(II) Complexes Doing the Cha-Cha with the C-t-CCL-28 Peptide, Dancing till the End of Microbes.

The necessity to move away from conventional antibiotic therapy has sparked interest in antimicrobial peptides (AMPs). One fascinating example is human CCL-28 chemokine produced by acinar epithelial cells in the salivary glands. It can also be released into the oral cavity with saliva, playing a crucial role in oral protection. The C-terminal domain of CCL-28 possesses antifungal and antibacterial properties, which are likely linked to membrane disruption and enzyme leakage. Studies suggest that AMPs can become more potent after they have bound Cu(II) or Zn(II). In many cases, these ions are essential for maximizing effectiveness by altering the peptides' physicochemical properties, such as their local charge or structure. The examined peptide binds Cu(II) and Zn(II) ions very effectively, forming equimolar complexes. Metal ion binding affinity, coordination mode, and antimicrobial activity strongly depend on the pH of the environment. Coordination modes have been proposed based on the results of potentiometric titrations, spectroscopic studies (UV-visible, electron paramagnetic resonance and circular dichroism at different path lengths), and mass spectrometry. The antimicrobial properties of the Cu(II) and Zn(II) complexes with the C-terminal fragment of CCL-28 chemokine have been assessed against fungal and bacterial strains, demonstrating exceptional activity against Candida albicans at pH 5.4. Moreover, the complex with Zn(II) ions shows the same activity against theStreptococcus mutans bacterium as chloramphenicol, a commonly used antibiotic. Cyclic voltammetry proposed a probable antimicrobial mechanism of the studied Cu(II) complex through the formation of reactive oxygen species, which was also confirmed by tests with ascorbic acid in UV-vis and fluorescence spectroscopic studies.