tyrosyl-tRNA Synthetase Research Articles

Antimicrobial Potential of Sphaeranthus indicus Against Staphylococcus aureus: A Computational Approach

Sphaeranthus indicus is one of the multipurpose medicinal plants widely used as antimicrobial, wound-healing, anti-arthritics, immunostimulant, immunomodulatory, neuroleptic, etc. activities. Computer-aided drug discovery/design (CADD) methods have been developed to identify the promising compounds with advantage over complexity, cost, time consumption, risk and may lead to their development as drugs. The aim of this study is to evaluate the antimicrobial potential of phytochemicals from Sphaeranthus indicus through Molecular docking and ADMET prediction. In this study, 54 bioactive compounds from Sphaeranthus indicus were tested against four bacterial target protein tyrosyl tRNA synthetase, Dihydrofolate reductase, Gyrase B and sortase A of Staphylococcus aureus to determine the potential antimicrobial activity of Sphaeranthus indicus. This study is investigated with the help of molecular docking study and ADMET prediction method. 14 compounds were found as potential inhibitor of Staphylococcus aureus by inhibiting either one or four target protein. These compounds were found to be safe and have good ADMET properties and showed promising potentials that may lead to their development as drugs target against Staphylococcus aureus.

Structural Fluctuation in Homodimeric Aminoacyl-tRNA Synthetases Induces Half-of-the-Sites Activity.

Enzymatic activity is regulated by various mechanisms to ensure biologically proper functions. Notable instances of such regulation in homodimeric enzymes include "all-of-the-sites activity" and "half-of-the-sites activity". The difference in these activities lies in whether one or both of the subunits are simultaneously active. Owing to its uniqueness, the mechanism of half-of-the-sites activity has been widely investigated. Consequently, structural asymmetry derived from cooperative motion is considered to induce half-of-the-sites activity. In contrast, recent investigations have suggested that subunit-intrinsic properties or structural fluctuation also induces structural asymmetry. Hence, the mechanism underlying half-of-the-sites activity has not been completely elucidated. Additionally, most previous studies have focused only on half-of-the-sites activity. Therefore, by comparing the structural and dynamical properties of two representative homodimers exhibiting all-of-the-sites and half-of-the-sites activities, respectively, we attempted to elucidate the mechanism of half-of-the-sites activity. Specifically, all-atom molecular dynamics simulations were applied to lysyl-tRNA synthetase and tyrosyl-tRNA synthetase. Our analysis revealed that structural fluctuation is sufficient to induce structural asymmetry in addition to the well-established factor of cooperative motion. Considering that structural fluctuation is a common characteristic of any enzyme, it could be a general factor in half-of-the-sites activity.

Pyrimidine appended heterocycles: synthesis, characterization, and biological evaluation

A new class of pyrimidine-based heterocycles has been successfully synthesized via a simple and efficient way starting from 2-keto-thiophene (1). The α,β-unsaturated ketone (chalcone) (3) was first synthesized by treating the ketone (1) with 4-methoxy benzaldehyde (2), followed by treating with amino formamidine hydrochloride to afford the intermediate pyrimidine moiety (4) which was converted to amide functionalized pyrimidines (5a–e), pyrimidine-2-imines (6a–e) and thiophene tethered pyrimidine-imidazoles (7a–e). The structures assigned to the new compounds are confirmed by IR, NMR, and MS studies. The newly synthesized compounds were subjected to a molecular docking study with the protein of Staphylococcus aureus (PDB ID: 1JIJ), for antioxidant and antibacterial activity. The compounds 5a, 6a, 6b, and 7d were found to show hydrogen bond interaction with active site amino acid residues with the binding energy of −8,08, −8.39, −8.64, and −8.02 kJ/mol, respectively, and may act as potential inhibitors of bacterial tyrosyl-tRNA synthetases. The biological study envisioned that the synthesized compound 7b has shown potent antioxidant properties with 74.07% scavenging activity at 400 µg/mL and compound 6b was found to exhibit excellent antibacterial activity with 16, 20, 21, and 22 mm zone of inhibition against S. aureus, Escherichia coli, Salmonella paratyphi-A and Bacillus subtilis bacterial strains, respectively.

Identification of Essential Oils Morrocan Pulicaria Mauritanica Phytochemical Compounds, In-Silico and In Vitro Investigation of Antibacterial and Antioxidant Activity.

A study was conducted to analyze the essential oil ofPulicariamauritanica(PMEO) and investigate its antibacterial and antioxidant properties using in vitro and in-silico methods. The essential oil was extracted using the hydrodistillation technique, and its chemical composition was identified via GC/MS analysis. The chemical composition of oil shows that the major components of PMEO arecarvotanacetone(67.92%) followed by 2,5-dimethoxy-p-cymene (3.62%), eucalyptol (1.76%) and tetrahydrocarvone (1.32%). The antibacterial and antioxidant effects against DPPH free radicals andferric reducingpower were tested using the in vitro microdilution method. The antibacterial activity showed a strong sensitivity againstBacillus subtilisandProteus mirabiliswith an inhibition zone of (22.33 ± 1.78 mm and 19.3 ± 0.68 mm, respectively; the lowest MIC and MBC values were (MIC=MBC=1.56 mg/mL). However, computational studies were carried out using molecular docking studies. The study of the interaction nature between (PMEO) essential oil and tyrosyl-tRNA synthetase fromStaphylococcus aureusaids in understanding the antibacterial properties of essential oil molecules and their mechanism of action. The in-silico toxicity and pharmacokinetics results show that 4-candidate molecules have potential antibacterial drugs andsuggeststhat PMEO could be a source of natural antioxidants and antibacterial agents.

Assessment of silver and graphitic carbon nitride doped cadmium selenide quantum dots as an efficient dye degrader and antibacterial agent: In silico molecular docking analysis

This study demonstrates the synthesis of co-precipitated cadmium selenide (CdSe) quantum dots (QDs) doped with (2 and 4 wt %) of silver (Ag) and fixed quantity of graphitic carbon nitride (g-C3N4) for catalytic as well as antibacterial potential with molecular docking (MD) analysis. Comprehensive characterizations investigated the structural composition, surface morphology, elemental composition, and optical properties. XRD revealed the multiple phases (hexagonal and cubic) of CdSe with a notable rise in the diffraction peaks intensity upon doping. The optical studies demonstrated the range of absorption peaks, which increased upon doping confirmed through band gap energies significantly altered. TEM study revealed that a sheet of g-C3N4 overlapped with CdSe QDs, and certain nanorod-like structures emerged after Ag doping. HR-TEM was employed for the d-spacing computation of prepared samples and exposed a decreasing trend as the Ag concentration increased. Furthermore, the catalytic activity (CA) performed against RhB dye showed maximum results in the acidic medium with a higher concentration of Ag into g-C3N4 doped CdSe. The efficient bactericidal efficacy was evaluated against S. aureus bacteria with the highest inhibition zone of 13.75 mm for 4% Ag doping, which was further explained by investigating their inhibitory effects on DNA gyrase and tyrosyl-tRNA synthetase via MD.

In silico Identification of Potential Inhibitors against Staphylococcus aureus Tyrosyl-tRNA Synthetase.

Drug-resistant Staphylococcus aureus (S. aureus) has spread from nosocomial to community-acquired infections. Novel antimicrobial drugs that are effective against resistant strains should be developed. S. aureus tyrosyl-tRNA synthetase (saTyrRS) is considered essential for bacterial survival and is an attractive target for drug screening. The purpose of this study was to identify potential new inhibitors of saTyrRS by screening compounds in silico and evaluating them using molecular dynamics (MD) simulations. A 3D structural library of 154,118 compounds was screened using the DOCK and GOLD docking simulations and short-time MD simulations. The selected compounds were subjected to MD simulations of a 75-ns time frame using GROMACS. Thirty compounds were selected by hierarchical docking simulations. The binding of these compounds to saTyrRS was assessed by short-time MD simulations. Two compounds with an average value of less than 0.15 nm for the ligand RMSD were ultimately selected. The longtime (75 ns) MD simulation results demonstrated that two novel compounds bound stably to saTyrRS in silico. Two novel potential saTyrRS inhibitors with different skeletons were identified by in silico drug screening using MD simulations. The in vitro validation of the inhibitory effect of these compounds on enzyme activity and their antibacterial effect on drug-resistant S. aureus would be useful for developing novel antibiotics.

On the potential activity of hyaluronic acid as an antimicrobial agent: experimental and computational validations.

This century has seen the rise of antibiotic resistance as a significant public health problem. In addition, oxidative stress may also be a factor in selecting resistant strains of bacteria. The current study analyzed microbially produced hyaluronic acid's antibacterial activity and antioxidant activity. It had significant antibacterial action against strains of Staphylococcus aureus and Escherichia coli, with the IC50 value obtained being 487.65µgmL-1 for antioxidant assay. Our molecular docking investigations of hyaluronic acid on tyrosyl-tRNA synthetase (Staphylococcus aureus: -6.13kcal/mol, Escherichia coli: -5.79kcal/mol) and topoisomerase II DNA gyrase (Staphylococcus aureus: -5.02kcal/mol, Escherichia coli: -4.90kcal/mol) confirmed the ligands' possible binding mode to the appropriate targets' sites. We also employed molecular dynamics simulation and showed that HA binds more strongly with 1JIL (-85.455 ± 12.623kJ/mol) compared to 2YXN (-49.907 ± 64.191kJ/mol), 5CDP (-47.285 ± 13.925kJ/mol), and 6RKS (-45.306 ± 21.338kJ/mol). We also report that the ligand forms several hydrogen bonds in molecular simulation, implying regular interaction with key residues of the enzymes. The results in this study indicate the potential use of HA in the vast field of applications having both asthetic and medicinal values.

Murine nuclear tyrosyl-tRNA synthetase deficiency leads to fat storage deficiency and hearing loss

Aminoacyl-tRNA synthetases are fundamental to the translation machinery with emerging roles in transcriptional regulation. Previous cellular studies have demonstrated tyrosyl-tRNA synthetase (YARS1 or TyrRS) as a stress response protein through its cytosol-nucleus translocation to maintain cellular homeostasis. Here, we established a mouse model with a disrupted TyrRS nuclear localization signal, revealing its systemic impact on metabolism. Nuclear TyrRS deficiency (YarsΔNLS) led to reduced lean mass, reflecting a mild developmental defect, and reduced fat mass, possibly due to increased energy expenditure. Consistently, YarsΔNLS mice exhibit improved insulin sensitivity and reduced insulin levels, yet maintain normoglycemia, indicative of enhanced insulin action. Notably, YarsΔNLS mice also develop progressive hearing loss. These findings underscore the crucial function of nuclear TyrRS in the maintenance of fat storage and hearing and suggest that aminoacyl-tRNA synthetases' regulatory roles can affect metabolic pathways and tissue-specific health. This work broadens our understanding of how protein synthesis interconnects metabolic regulation to ensure energy efficiency.

Synthesis, Structural Characterization, and Computational Studies of Novel Co(II) and Zn(II) Fluoroquinoline Complexes for Antibacterial and Antioxidant Activities.

Research into heterocyclic ligands has increased in popularity due to their versatile applications in the biomedical field. Quinoline derivatives with their transition metal complexes are popular scaffolding molecules in the ongoing pursuit of newer and more effective bioactive molecules. Subsequently, this work reports on the synthesis and possible biological application of new Zn(II) and Co(II) complexes with a bidentate quinoline derivative ligand (H2 L), [(H2 L):(E)-2-(((6-fluoro-2-((2-hydroxyethyl)amino)quinolin-3-yl)methylene)amino)ethanol]. The ligand and its metal complexes were structurally characterized by spectroscopic methods (1H NMR, 13C NMR, Fourier transform infrared (FTIR), UV-vis, fluorescence, and mass spectroscopy), as well as by thermogravimetric and elemental analysis methods. The spectroscopic findings were further supported by density functional theory (DFT) and time-dependent (TD)-DFT calculations. The biological application was examined by investigating the inhibitory action of the complexes against bacterial strains using diffusion and agar dilution methods, and their profiles against two Gram-positive and Gram-negative bacterial strains were supported by molecular docking analysis. To rationalize the in vitro activity and establish the possible mechanism of action, the interactions and binding affinity of the ligand and complexes were investigated against three different bacterial enzymes (Escherichia coli DNA gyrase (PDB ID 6f86), E. coli dihydrofolate reductase B (PDB ID: 7r6g), and Staphylococcus aureus tyrosyl-tRNA synthetase (PDB ID: 1JIJ)) using AutoDock with the standard protocol. The MIC value of 0.20 μg/mL for zinc complex against E. coli and associated binding affinities -7.2 and -9.9 kcal/mol with DNA gyrase (PDB ID 6f86) and dihydrofolate reductase B (PDB ID: 7r6g), as well as the MIC value of 2.4 μg/mL for cobalt(II) complex against Staphylococcus aureus and the associated binding affinity of -10.5 kcal/mol with tyrosyl-tRNA synthetase (PDB ID: 1JIJ), revealed that the complexes' inhibitory actions were strong and comparable with those of the standard drug in the experiments. In addition, the ability of the new quinoline-based complexes to scavenge 1,1-diphenyl-picrylhydrazyl radicals was investigated; the findings suggested that the complexes exhibit potent antioxidant activities, which may be of therapeutic significance.

Synthesis, characterization, and biological evaluation of novel cobalt(II) complexes with β-diketonates: crystal structure determination, BSA binding properties and molecular docking study.

In order to discover a new antibiotic drug with better or similar activity of the already existing drugs, a series of novel cobalt(II) complexes with β-diketonate as ligands is synthesized and tested on four strains of bacteria and four species of fungi. All compounds showed notable antimicrobial activityagainst all tested strains. More importantly, some cobalt(II) complexes displayed greater activity than ketoconazole. It is important to notice that on the tested strains Mucor mucedo and Penicillium italicum complex 2B showed five times better activity compared to ketoconazole, while complex 2D had two times better activity on Penicillium italicum strain compared to ketoconazole. Moreover, investigations with bovine serum albumin were performed. Investigations showed that the tested complexes have an appropriate affinity for binding to bovine serum albumin. In addition, the molecular docking study was performed to investigate more specifically the sites and binding mode of the tested cobalt(II) complexes with β-diketonate as ligands to bovine serum albumin, tyrosyl-tRNA synthetase, topoisomerase II DNA gyrase, and cytochrome P450 14 alpha-sterol demethylase. In conclusion, all the results indicated the great prospective of the novel cobalt complexes for some potential clinical applications in the future.

Synergistic effects of barium and PVP-doped Zn–Al layered double hydroxide for catalytic and antibacterial applications with molecular docking studies

Zinc-aluminum layered double hydroxide (Zn–Al LDH) doped with 3 wt% of polyvinyl pyrrolidone (PVP) and various concentrations (2 and 4 wt%) of barium (Ba) doped PVP-LDH were synthesized by co-precipitation method to effectively remove rhodamine-B (RhB) dye from wastewater and investigate its antibacterial properties against S. aureus. The composition and morphology of the layered structure were confirmed employing several characterization techniques: X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). Dopants into LDH enhanced oxygen vacancies, increasing the number of active sites and demonstrating superior capability to degrade RhB dye. The results also revealed that doped LDH effectively inhibits the biofilm formation of S. aureus bacteria. The 4 wt% Ba doped sample exhibited a maximal degradation (93.92 %) in basic medium and 72.66 % antimicrobial efficiency against S. aureus. To confirm the effectiveness of PVP and Ba-doped LDH as antimicrobial agents, molecular docking investigations were carried out targeting the DNA gyrase and tyrosyl-tRNA synthetase enzymes of S. aureus.

Native Aminoacyl-tRNA Synthetase/tRNA Pair Drives Highly Efficient Noncanonical Amino Acid Incorporation in Escherichia coli.

Site-specific noncanonical amino acid (ncAA) mutagenesis in living cells has traditionally relied on heterologous, nonsense-suppressing aminoacyl-tRNA synthetase (aaRS)/tRNA pairs that do not cross-react with their endogenous counterparts. Such heterologous pairs often perform suboptimally in a foreign host cell since they were not evolutionarily optimized to function in the foreign environment. This suboptimal performance restricts the number of ncAAs that can be simultaneously incorporated into a protein. Here, we show that the use of an endogenous aaRS/tRNA pair to drive ncAA incorporation can offer a potential solution to this limitation. To this end, we developed an engineered Escherichia coli strain (ATMY-C321), wherein the endogenous tyrosyl-tRNA synthetase (TyrRS)/tRNA pair has been functionally replaced with an archaeal counterpart, and the release factor 1 has been removed to eliminate competing termination at the UAG nonsense codons. The endogenous TyrRS/tRNACUATyr pair exhibits remarkably efficient nonsense suppression in the resulting cell, relative to established orthogonal ncAA-incorporation systems in E. coli, allowing the incorporation of an ncAA at up to 10 contiguous sites in a reporter protein. Our work highlights the limitations of orthogonal translation systems using heterologous aaRS/tRNA pairs and offers a potential alternative involving the use of endogenous pairs.

Antibacterial, antibiofilm, and chemical profiles of Ammi visnaga L. and Foeniculum vulgare mill. Essential oils, and ADMET, molecular docking investigation of essential oils major components

This study determined chemical profiles, antibacterial and antibiofilm activities of the essential oils (EOs) obtained by A. visnaga aerial parts and F. vulgare fruits. Butanoic acid, 2-methyl-, 3-methylbutyl ester (38.8%), linalyl propionate (34.7%) and limonene (8.5%) resulted as main constituents of A. visnaga EO. In F. vulgare EO trans-anethole (76.9%) and fenchone (14.1%) resulted as main components. The two EOs were active against five bacterial strains (Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus) at different degrees. The MIC values ranged from 5 ± 2 to 10 ± 2 μL/mL except for S. aureus (MIC >20 μL/mL). EOs exhibited inhibitory effect on the formation of biofilm up to 53.56 and 48.04% against E. coli and A. baumannii, respectively and activity against bacterial metabolism against A. baumannii and E. coli, with biofilm-inhibition ranging from 61.73 to 73.55%. The binding affinity of the identified components was estimated by docking them into the binding site of S. aureus gyrase (PDB code 2XCT) and S. aureus tyrosyl-tRNA synthetase (PDB code 1JIJ). trans-Anethole and butanoic acid, 2-methyl-, 3-methylbutyl ester showed relatively moderate binding interactions with the amino acid residues of S. aureus tyrosyl-tRNA synthetase. In addition, almost all predicted compounds possess good pharmacokinetic properties with no toxicity, being inactive for cytotoxicity, carcinogenicity, hepatotoxicity, mutagenicity and immunotoxicity parameters. The results encourage the use of these EOs as natural antibacterial agents in food and pharmaceutical industries.

Development of orthogonal aminoacyl-tRNA synthetase mutant for incorporating a non-canonical amino acid

Genetic code expansion involves introducing non-canonical amino acids (ncAAs) with unique functional groups into proteins to broaden their applications. Orthogonal aminoacyl tRNA synthetase (aaRS), essential for genetic code expansion, facilitates the charging of ncAAs to tRNA. In this study, we developed a new aaRS mutant from Methanosaeta concilii tyrosyl-tRNA synthetase (Mc TyrRS) to incorporate para-azido-l-phenylalanine (AzF). The development involved initial site-specific mutations in Mc TyrRS, followed by random mutagenesis. The new aaRS mutant with amber suppression was isolated through fluorescence-activated cell sorting. The M. concilii aaRS mutant structure was further analyzed to interpret the effect of mutations. This research provides a novel orthogonal aaRS evolution pipeline for highly efficient ncAA incorporation that will contribute to developing novel aaRS from various organisms.

Investigating the molecular interactions of 11-substituted-1-(4-chlorophenyl)-8H-indolo[3,2-c][1,2,4]triazolo[3,4-a]isoquinolines for Antimicrobial Potential: Synthesis, Spectral, In vitro and In silico study interpretations

Indole molecules are one of the important scaffolds in the discovery and development of new drugs. We herein described a synthesis of new 11-substituted-1-(4-chlorophenyl)-8H-indolo[3,2-c][1,2,4]triazolo[3,4-a]isoquinoline 6 (a-h). Structures of the newly synthesized compounds were confirmed by making use of spectroscopic techniques like IR, NMR and mass. The DFT calculations were taken for the selected molecules using CAM-B3LYP hybrid functional with a 6–31+g(d) all-electron basis set using the Gaussian 09 package. The drug-likeness calculations were explained for the synthesized derivatives. The compounds 6b, 6c and 6 g exhibited excellent antibacterial, antifungal and anti-TB activities against tested pathogens at MIC 3.125 μg/ml. Furthermore, molecular docking studies of these compounds against S. aureus Gyrase (PDB ID:2XCT), Staphylococcus aureus tyrosyl-tRNA synthetase (PDB ID:1JIJ), and Mycobacterium tuberculosis enoyl reductase (INHA) (PDB ID:4TZK), revealed the potential binding mode of the ligands to the site of the appropriate targets. Finally, drug likeness and SAR studies were disclosed. Lastly, the protein stability, fluctuations of APO-Protein, and protein-ligand complexes were investigated through molecular dynamics simulations studies using Desmond Maestro 11.3 and potential lead molecules were identified.

Novel hybrid thiazoles, bis-thiazoles linked to azo-sulfamethoxazole: Synthesis, docking, and antimicrobial activity

The reaction of sulfamethoxazolehydrazonoyl chloride with thiosemicarbazones, bis-thiosemicarbazones, or 4-amino-3-mercapto-1,2,4-triazole in dioxane in the presence of triethylamine as a basic catalyst at reflux resulted in the regioselective synthesis of thiazoles and bis-thiazoles linked to azo-sulfamethoxazole as novel hybrid molecules. The structures of the new compounds were confirmed using a range of spectra. Each compound's antibacterial properties were evaluated using the agar well-diffusion technique, and most of them demonstrated significant potency. In silico investigations revealed that the described compounds had strong interactions with the binding sites of MurE ligase, tyrosyl-tRNA synthetase, and dihydropteroate synthase, demonstrating inhibitory activity.

Bio-capped multifunctional CuO nanoparticles via Knautia arvensis for dye removal, antibacterial and antifungal efficiency, and molecular docking

Copper oxide nanoparticles (CuONPs) synthesized using Knautia arvensis flower extract in an environmentally friendly and one-step procedure were characterized by UV–vis, FT-IR, SEM and DLS. The in vitro antibacterial and antifungal activities of CuONPs were determined using E. coli, S. aureus and A. niger. In silico antibacterial and antifungal evaluation of CuONPs were performed by molecular docking analysis using chitin deacetylase of A. niger, topoisomerase IV of E. coli and tyrosyl-tRNA synthetase of S. aureus. The best binding energy was determined using these microbial targets in molecular docking analyses and the antimicrobial mechanisms between the microorganism and the CuONP were elucidated. The degradation potential of Remazol brilliant blue R (RBBR) and Napthol blue black (NBB) dyes in the presence of CuONPs were investigated. The peak obtained at 289 nm as a result of UV–vis analysis revealed the presence of CuONPs. The spherical morphology of CuONPs and the particle size varying between 88–289 nm were visualized by SEM. DLS analysis pointed out the mean diameter of CuONPs was 189 nm along with the PDI value of 0.324. The 600 and 595 cm−1 vibrations attained in the FT-IR spectroscopy showed the presence of CuONPs. In addition, the presence of phenolic compounds found in the plant extract responsible for bio-capping of copper ions into CuONPs were enlightened by the FT-IR analysis. Dye degradation activity of CuONPs was found as 69% and 71% using NBB and RBBR at 50 °C in 90 min, respectively. Antifungal and antibacterial interactions of CuONPs with chitin deacetylase of A. niger, topoisomerase IV of E. coli and tyrosyl-tRNA synthetase of S. aureus were analyzed in order to reveal the antimicrobial mechanisms of CuONPs and it was found that CuONPs demonstrate significant interactions with those proteins with binding energies −7.25, −7.14 and −7.89 kcal mol−1, respectively.

Competitive Inhibition of Okanin against Plasmodium falciparum Tyrosyl-tRNA Synthetase.

Malaria is a severe disease that presents a significant threat to human health. As resistance to current drugs continues to increase, there is an urgent need for new antimalarial medications. Aminoacyl-tRNA synthetases (aaRSs) represent promising targets for drug development. In this study, we identified Plasmodium falciparum tyrosyl-tRNA synthetase (PfTyrRS) as a potential target for antimalarial drug development through a comparative analysis of the amino acid sequences and three-dimensional structures of human and plasmodium TyrRS, with particular emphasis on differences in key amino acids at the aminoacylation site. A total of 2141 bioactive compounds were screened using a high-throughput thermal shift assay (TSA). Okanin, known as an inhibitor of LPS-induced TLR4 expression, exhibited potent inhibitory activity against PfTyrRS, while showing limited inhibition of human TyrRS. Furthermore, bio-layer interferometry (BLI) confirmed the high affinity of okanin for PfTyrRS. Molecular dynamics (MD) simulations highlighted the stable conformation of okanin within PfTyrRS and its sustained binding to the enzyme. A molecular docking analysis revealed that okanin binds to both the tyrosine and partial ATP binding sites of the enzyme, preventing substrate binding. In addition, the compound inhibited the production of Plasmodium falciparum in the blood stage and had little cytotoxicity. Thus, okanin is a promising lead compound for the treatment of malaria caused by P. falciparum.

Design, Synthesis, Biological Evaluation and in Silico Studies of Curcumin Pyrrole Conjugates.

Curcumin conjugated heterocyclic compounds are potent candidates with drug likeness against various bacterial pathogens. A set of curcumin-based pyrrole conjugates (CPs) were synthesized and characterized by FT-IR, 1H and 13C NMR and HR-MS techniques. The results of free radical scavenging activity of the synthesized CPs, evaluated by FRAP and CUPRAC assays, showed the potency of these compounds as effective antioxidants. CP3 exhibits the highest antioxidant activity amongst the CPs. The bactericidal efficacy of CPs was screened against ESKAP bacterial pathogens, and CPs were found to possess better antibacterial property than curcumin, specifically against staphylococcus aureus bacteria. In addition, serum albumin (BSA and HSA) binding interaction of these CPs were determined by UV-visible and fluorescence spectrophotometric techniques. In-silico molecular docking study was performed to determine the binding patterns of molecular targets against Staphylococcus aureus tyrosyl tRNA synthetase, and serum albumin proteins. The structure-activity relationship showed that the presence of multiple phenolic hydroxyl groups, and electron withdrawing groups on the structure of CP molecule, enhances its antioxidant and antibacterial activity, respectively.

Boosting BDNF in muscle rescues impaired axonal transport in a mouse model of DI-CMTC peripheral neuropathy

Charcot-Marie-Tooth disease (CMT) is a genetic peripheral neuropathy caused by mutations in many functionally diverse genes. The aminoacyl-tRNA synthetase (ARS) enzymes, which transfer amino acids to partner tRNAs for protein synthesis, represent the largest protein family genetically linked to CMT aetiology, suggesting pathomechanistic commonalities. Dominant intermediate CMT type C (DI-CMTC) is caused by YARS1 mutations driving a toxic gain-of-function in the encoded tyrosyl-tRNA synthetase (TyrRS), which is mediated by exposure of consensus neomorphic surfaces through conformational changes of the mutant protein. In this study, we first showed that human DI-CMTC-causing TyrRSE196K mis-interacts with the extracellular domain of the BDNF receptor TrkB, an aberrant association we have previously characterised for several mutant glycyl-tRNA synthetases linked to CMT type 2D (CMT2D). We then performed temporal neuromuscular assessments of YarsE196K mice modelling DI-CMT. We determined that YarsE196K homozygotes display a selective, age-dependent impairment in in vivo axonal transport of neurotrophin-containing signalling endosomes, phenocopying CMT2D mice. This impairment is replicated by injection of recombinant TyrRSE196K, but not TyrRSWT, into muscles of wild-type mice. Augmenting BDNF in DI-CMTC muscles, through injection of recombinant protein or muscle-specific gene therapy, resulted in complete axonal transport correction. Therefore, this work identifies a non-cell autonomous pathomechanism common to ARS-related neuropathies, and highlights the potential of boosting BDNF levels in muscles as a therapeutic strategy.