Displaying publications 61 - 80 of 256 in total

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  1. RAGE and TLRs: relatives, friends or neighbours?
    Ibrahim ZA, Armour CL, Phipps S, Sukkar MB
    Mol Immunol, 2013 Dec;56(4):739-44.
    PMID: 23954397 DOI: 10.1016/j.molimm.2013.07.008
    The innate immune system forms the first line of protection against infectious and non-infectious tissue injury. Cells of the innate immune system detect pathogen-associated molecular patterns or endogenous molecules released as a result of tissue injury or inflammation through various innate immune receptors, collectively termed pattern-recognition receptors. Members of the Toll-like receptor (TLR) family of pattern-recognition receptors have well established roles in the host immune response to infection, while the receptor for advanced glycation end products (RAGE) is a pattern-recognition receptor predominantly involved in the recognition of endogenous molecules released in the context of infection, physiological stress or chronic inflammation. RAGE and TLRs share common ligands and signaling pathways, and accumulating evidence points towards their co-operative interaction in the host immune response. At present however, little is known about the mechanisms that result in TLR versus RAGE signalling or RAGE-TLR cross-talk in response to their shared ligands. Here we review what is known in relation to the physicochemical basis of ligand interactions between TLRs and RAGE, focusing on three shared ligands of these receptors: HMGB1, S100A8/A9 and LPS. Our aim is to discuss what is known about differential ligand interactions with RAGE and TLRs and to highlight important areas for further investigation so that we may better understand the role of these receptors and their relationship in host defense.
    Matched MeSH terms: Ligands
  2. Fulltext Novel Complex of Zinc (II) Dichloroethylenediamine: Synthesis, Characterization, In-silico, and In-vitro Evaluation against Cervical Cancer Cells
    Raya I, Kartina D, Wijaya RI, Irfandi R, Abdalrazaq EA, Prihantono P, et al.
    Asian Pac J Cancer Prev, 2023 Dec 01;24(12):4155-4165.
    PMID: 38156851 DOI: 10.31557/APJCP.2023.24.12.4155
    OBJECTIVE: Cervical cancer is a malignancy originating from the cervix and often caused by oncogenic Human Papilloma Virus (HPV), specifically subtypes 16 and 18. Anticancer drugs are chemotherapeutic compounds used for cancer treatment. Therefore, this research aims to synthesize and characterize Zinc (II) dichloroethylenediamine (Zn(en)Cl2) complex, as well as determine its antiproliferative activity against HeLa cells. The Zn(en)Cl2 complex was successfully synthesized, and the antiproliferative activity was tested.

    METHODS: The synthesis involved reacting ethylenediamine and KCl with Zn metal. The complex formed was characterized using a conductometer, UV-Vis spectroscopy, FT-IR spectroscopy, and XRD, while the activity was measured against HeLa cells.

    RESULT: The synthesis yielded a 56.12% conversion with a melting point of 198-200 oC and a conductivity value of 2.02 mS/cm. The Zn(en)Cl2 complex showed potential activity against HeLa cells with an IC50 value of 898.35 µg/mL, which was evidenced by changes in the morphological structure of HeLa cells. Its interaction with DNA targets was investigated by employing molecular docking.

    CONCLUSION: The observed data indicated that the Zn(en)Cl2 complex bound to DNA at the nitrogenous base Guanine (DG) by coordinate covalent bonds. Interestingly, DG maintained interaction with the complex until the end of the docking simulation. Additionally, molecular dynamics (MD) simulation was conducted, and the results showed that Zn(en)Cl2 remained bound to the DNA binding pocket all through the process.

    Matched MeSH terms: Ligands
  3. An in silico approach towards the identification of novel inhibitors of the TLR-4 signaling pathway
    Mahita J, Harini K, Rao Pichika M, Sowdhamini R
    J Biomol Struct Dyn, 2016 Jun;34(6):1345-62.
    PMID: 26264972 DOI: 10.1080/07391102.2015.1079243
    Precise functioning and fine-tuning of Toll-like receptor 4 (TLR4) signaling is a critical requirement for the smooth functioning of the innate immune system, since aberrant TLR4 activation causes excessive production of pro-inflammatory cytokines and interferons. This can result in life threatening conditions such as septic shock and other inflammatory disorders. The TRIF-related adaptor molecule (TRAM) adaptor protein is unique to the TLR4 signaling pathway and abrogation of TRAM-mediated TLR4 signaling is a promising strategy for developing therapeutics aimed at disrupting TRAM interactions with other components of the TLR4 signaling complex. The VIPER motif from the vaccinia virus-producing protein, A46 has been reported to disrupt TRAM-TLR4 interactions. We have exploited this information, in combination with homology modeling and docking approaches, to identify a potential binding site on TRAM lined by the BB loop and αC helix. Virtual screening of commercially available small molecules targeting the binding site enabled to short-list 12 small molecules to abrogate TRAM-mediated TLR4 signaling. Molecular dynamics and molecular mechanics calculations have been performed for the analysis of these receptor-ligand interactions.
    Matched MeSH terms: Ligands*
  4. Neuropsychiatric implications of transient receptor potential vanilloid (TRPV) channels in the reward system
    Singh R, Bansal Y, Parhar I, Kuhad A, Soga T
    Neurochem Int, 2019 12;131:104545.
    PMID: 31494132 DOI: 10.1016/j.neuint.2019.104545
    Neuropsychiatric disorders (NPDs) exert a devastating impact on an individual's personal and social well-being, encompassing various conditions and brain anomalies that influence affect, cognition, and behavior. Because the pathophysiology of NPDs is multifactorial, the precise mechanisms underlying the development of such disorders remain unclear, representing a unique challenge in current neuropsychopharmacotherapy. Transient receptor potential vanilloid (TRPV) type channels are a family of ligand-gated ion channels that mainly include sensory receptors that respond to thermal, mechanical and chemical stimuli. TRPV channels are abundantly present in dopaminergic neurons, thus playing a pivotal role in the modulation of the reward system and in pathophysiology of diseases such as stress, anxiety, depression, schizophrenia, neurodegenerative disorders and substance abuse/addiction. Recent evidence has highlighted TRPV channels as potential targets for understanding modulation of the reward system and various forms of addiction (opioids, cocaine, amphetamines, alcohol, nicotine, cannabis). In this review, we discuss the distribution, physiological roles, ligands and therapeutic importance of TRPV channels with regard to NPDs and addiction biology.
    Matched MeSH terms: Ligands
  5. Fulltext Chaos-embedded particle swarm optimization approach for protein-ligand docking and virtual screening
    Tai HK, Jusoh SA, Siu SWI
    J Cheminform, 2018 Dec 14;10(1):62.
    PMID: 30552524 DOI: 10.1186/s13321-018-0320-9
    BACKGROUND: Protein-ligand docking programs are routinely used in structure-based drug design to find the optimal binding pose of a ligand in the protein's active site. These programs are also used to identify potential drug candidates by ranking large sets of compounds. As more accurate and efficient docking programs are always desirable, constant efforts focus on developing better docking algorithms or improving the scoring function. Recently, chaotic maps have emerged as a promising approach to improve the search behavior of optimization algorithms in terms of search diversity and convergence speed. However, their effectiveness on docking applications has not been explored. Herein, we integrated five popular chaotic maps-logistic, Singer, sinusoidal, tent, and Zaslavskii maps-into PSOVina[Formula: see text], a recent variant of the popular AutoDock Vina program with enhanced global and local search capabilities, and evaluated their performances in ligand pose prediction and virtual screening using four docking benchmark datasets and two virtual screening datasets.

    RESULTS: Pose prediction experiments indicate that chaos-embedded algorithms outperform AutoDock Vina and PSOVina in ligand pose RMSD, success rate, and run time. In virtual screening experiments, Singer map-embedded PSOVina[Formula: see text] achieved a very significant five- to sixfold speedup with comparable screening performances to AutoDock Vina in terms of area under the receiver operating characteristic curve and enrichment factor. Therefore, our results suggest that chaos-embedded PSOVina methods might be a better option than AutoDock Vina for docking and virtual screening tasks. The success of chaotic maps in protein-ligand docking reveals their potential for improving optimization algorithms in other search problems, such as protein structure prediction and folding. The Singer map-embedded PSOVina[Formula: see text] which is named PSOVina-2.0 and all testing datasets are publicly available on https://cbbio.cis.umac.mo/software/psovina .

    Matched MeSH terms: Ligands
  6. A new sensitive electrochemical method for the determination of vanadium(IV) and vanadium(V) in Benfield sample
    Qureshi MS, Mohd Yusoff AR, Shah A, Nafady A, Sirajuddin
    Talanta, 2015 Jan;132:541-7.
    PMID: 25476342 DOI: 10.1016/j.talanta.2014.10.005
    Vanadium(IV) and vanadium(V) can be determined by using differential pulse cathodic stripping voltammetry technique (DPCSV). Cupferron (ammonium N-nitrosophenylhydroxylamine) was used as ligand to form complex compounds with vanadium ions in Britton-Robinson buffer (BRB) solution. At concentration lower than 1.0×10(-6) M, both V(IV) and V(V) cupferron complexes showed a single cathodic peak at -0.576 V in BRB of pH 4; thus V(IV) and V(V) ions cannot be differentiated at low concentration. However, the ionic species of vanadium can be differentiated at high concentration in the presence of cupferron. Parameters including pH of BRB solution, initial potential and accumulation potential were optimized. Under the optimized parameters, the limit of detection (LOD) was 0.09 nM, and the peak current was linear in the concentration range 0.01-0.9 µM total vanadium ions. The determination of V(IV) and V(V) ions was carried out at higher concentration in the sample using calibration plot method. At higher concentration range of 10-60 µM V(IV) and V(V) ions were determined with LOD of 1.2 and 1.1 µM, respectively. The developed method was successfully applied to 10,00,000 fold diluted Benfield sample and 0.6227 M total vanadium ions were determined. The determination of V(IV) and V(V) ions were also successfully carried out in artificial sample as well as Benfield sample (dilution factor, 10,000). The concentration of V(IV) and V(V) ions was 22.52 µM and 38.91 µM, respectively, giving total vanadium concentration of 0.6143 M in Benfield sample.
    Matched MeSH terms: Ligands
  7. Fulltext Expression of fibroblast growth factor receptor 4 (FGFR-4) in nasopharyngeal carcinoma (NPC) cell lines and its potential as therapeutic target
    Hooi Yeen Yap, Jack Bee Chook, Sin Yeang Teow
    Malaysian Journal of Medicine and Health Sciences, 2019;15(108):49-49.
    MyJurnal
    ntroduction: Nasopharyngeal carcinoma (NPC) is a prevalent cancer among human population in Southern China, Hong Kong and Southeast Asia. In Malaysia, NPC is the fourth most common cancer in both sexes, predominantly in the Chinese. Epstein-Barr virus (EBV) infection is known to be highly associated with NPC. Fibroblast growth factor receptor-4 (FGFR4) is part of the family of tyrosine kinase receptors that regulate cell survival, differentiation and pro-liferation. The binding of FGFR4 ligands such as fibroblasts growth factors (FGFs) has been shown to activate various oncogenic signalling pathway including MAPK, Ras and PI3K-Akt pathways. In the past, FGFR4 has been shown to promote tumorigenesis and tumour progression in various cancers such as liver, colon, breast and pancreatic and gastric cancers. However, its role in NPC establishment and pathogenesis is under-explored. This study aimed to evaluate the FGFR4 expression in NPC using various cell lines and its potential as a therapeutic target for NPC treat-ment by gene silencing. Methods: The basal FGFR4 level of NPC (EBV-positive: C666-1 and EBV-negative: HONE1 and HK1) and nasopharyngeal epithelial (NPE) normal (NP69 and NP460) cell lines was determined by western blot analysis and RT-qPCR. FGFR4 level at different time points (0, 24, 48, and 72 hours) in HONE1 and C666-1 cell lines were determined by western blot analysis. Luminescence-based assay was performed to determine the cell prolifer-ation of NPC cells in correlation with the FGFR4 expression. NPC cells were then treated with the optimised FGFR4 siRNA or FGFR inhibitor, BLU-9931 and the silencing/ inhibition of FGFR4 expression was confirmed by western blot analysis. The effect of FGFR4 inhibition on the cell proliferation and aggressiveness of NPC cells was then investigat-ed through wound healing assay and invasion marker analysis. Results: Out of the five tested cell lines, HONE1 and C666-1 highly expressed FGFR4, NP69 showed very low expression while HK1 and NP460 did not express FGFR4. In the time-point study, the FGFR4 level of HONE1 and C666-1 peaked at 24-48 hours which is the exponential phase of cells. Following that, the FGFR4 level decreased corresponding to the decreased cell growth rate due to the nutrient deprivation. siRNA experiments showed that 6.25nM of four siRNAs (5, 6, 9 and 10) could effectively target and silence the FGFR4 expression of HONE1, but not in C666-1 even up to 250nM was tested. When BLU-9931 was used, only modest inhibition was observed in both cells at 3uM. Compared to the untreated control, FGFR4-inhibited HONE1 exhibited decreased cell proliferation rate. Cell migration and invasion capabilities of HONE1 were also significantly reduced following the FGFR4 silencing, suggesting the potential of utilising FGFR4 as the therapeutic target. Conclusion: FGFR4 is highly expressed in C666-1 (EBV-positive) and HONE1 (initially EBV-positive, but lost EBV genome in subsequent in vitro passage) NPC cells, but not in EBV-negative HK1 NPC cell and normal NPE cells. FGFR4 gene silencing effectively inhibited the cell proliferation, migration and invasive potentials of NPC cell line. These findings highlight the therapeutic value of targeting FGFR4 for NPC treatment. Further investigations are war-ranted to reveal the molecular mechanism and the possible role of EBV in regulating FGFR4 pathway.
    Matched MeSH terms: Ligands
  8. Molecular docking and dynamic simulation evaluation of Rohinitib - Cantharidin based novel HSF1 inhibitors for cancer therapy
    Agarwal T, Annamalai N, Khursheed A, Maiti TK, Arsad HB, Siddiqui MH
    J Mol Graph Model, 2015 Sep;61:141-9.
    PMID: 26245696 DOI: 10.1016/j.jmgm.2015.07.003
    Recent developments in the target based cancer therapies have identified HSF1 as a novel non oncogenic drug target. The present study delineates the design and molecular docking evaluation of Rohinitib (RHT) - Cantharidin (CLA) based novel HSF1 inhibitors for target-based cancer therapy. Here, we exploited the pharmacophoric features of both the parent ligands for the design of novel hybrid HSF1 inhibitors. The RHT-CLA ligands were designed and characterized for ADME/Tox features, interaction with HSF1 DNA binding domain and their pharmacophoric features essential for interaction. From the results, amino acid residues Ala17, Phe61, His63, Asn65, Ser68, Arg71 and Gln72 were found crucial for HSF1 interaction with the Heat shock elements (HSE). The hybrid ligands had better affinity towards the HSF1 DNA binding domain, in comparison to RHT or CLA and interacted with most of the active site residues. Additionally, the HSF1-ligand complex had a reduced affinity towards HSE in comparison to native HSF1. Based on the results, ligand RC15 and RC17 were non carcinogenic, non mutagenic, completely biodegradable under aerobic conditions, had better affinity for HSF1 (1.132 and 1.129 folds increase respectively) and diminished the interaction of HSF1 with HSE (1.203 and 1.239 folds decrease respectively). The simulation analysis also suggested that the ligands formed a stable complex with HSF1, restraining the movement of active site residues. In conclusion, RHT-CLA hybrid ligands can be used as a potential inhibitor of HSF1 for non-oncogene target based cancer therapy.
    Matched MeSH terms: Ligands
  9. Thiadiazole-, selenadiazole- and triazole-fused anthraquinones as G-quadruplex targeting anticancer compounds
    Andreeva DV, Vedekhina TS, Gostev AS, Dezhenkova LG, Volodina YL, Markova AA, et al.
    Eur J Med Chem, 2024 Mar 15;268:116222.
    PMID: 38387333 DOI: 10.1016/j.ejmech.2024.116222
    G-quadruplex (G4) ligands attract considerable attention as potential anticancer therapeutics. In this study we proposed an original scheme for synthesis of azole-fused anthraquinones and prepared a series of G4 ligands carrying amino- or guanidinoalkylamino side chains. The heterocyclic core and structure of the terminal groups strongly affect on binding to G4-forming oligonucleotides, cellular accumulation and antitumor potency of compounds. In particular, thiadiazole- and selenadiazole- but not triazole-based ligands inhibit the proliferation of tumor cells (e.g. K562 leukemia) and stabilize primarily telomeric and c-MYC G4s. Anthraselenadiazole derivative 11a showed a good affinity to c-MYC G4 in vitro and down-regulated expression of c-MYC oncogene in cellular conditions. Further studies revealed that anthraselenadiazole 11a provoked cell cycle arrest and apoptosis in a dose- and time-dependent manner inhibiting K562 cells growth. Taken together, this work gives a valuable example that the closely related heterocycles may cause a significant difference in biological properties of G4 ligands.
    Matched MeSH terms: Ligands
  10. Implication of HMGB1 signaling pathways in Amyotrophic lateral sclerosis (ALS): From molecular mechanisms to pre-clinical results
    Paudel YN, Angelopoulou E, Piperi C, Othman I, Shaikh MF
    Pharmacol Res, 2020 06;156:104792.
    PMID: 32278047 DOI: 10.1016/j.phrs.2020.104792
    Amyotrophic lateral sclerosis (ALS) is a devastating and rapidly progressing neurodegenerative disorder with no effective disease-modifying treatment up to date. The underlying molecular mechanisms of ALS are not yet completely understood. However, the critical role of the innate immune system and neuroinflammation in ALS pathogenesis has gained increased attention. High mobility group box 1 (HMGB1) is a typical damage-associated molecular pattern (DAMP) molecule, acting as a pro-inflammatory cytokine mainly through activation of its principal receptors, the receptor for advanced glycation end products (RAGE) and toll-like receptor 4 (TLR4) which are crucial components of the innate immune system. HMGB1 is an endogenous ligand for both RAGE and TLR4 that mediate its biological effects. Herein, on the ground of pre-clinical findings we unravel the underlying mechanisms behind the plausible contribution of HMGB1 and its receptors (RAGE and TLR4) in the ALS pathogenesis. Furthermore, we provide an account of the therapeutic outcomes associated with inhibition/blocking of HMGB1 receptor signalling in preventing motor neuron's death and delaying disease progression in ALS experimental models. There is strong evidence that HMGB1, RAGE and TLR4 signaling axes might present potential targets against ALS, opening a novel headway in ALS research that could plausibly bridge the current treatment gap.
    Matched MeSH terms: Ligands
  11. Role of Innate Immune Receptor TLR4 and its endogenous ligands in epileptogenesis
    Paudel YN, Angelopoulou E, Akyuz E, Piperi C, Othman I, Shaikh MF
    Pharmacol Res, 2020 10;160:105172.
    PMID: 32871246 DOI: 10.1016/j.phrs.2020.105172
    Understanding the interplay between the innate immune system, neuroinflammation, and epilepsy might offer a novel perspective in the quest of exploring new treatment strategies. Due to the complex pathology underlying epileptogenesis, no disease-modifying treatment is currently available that might prevent epilepsy after a plausible epileptogenic insult despite the advances in pre-clinical and clinical research. Neuroinflammation underlies the etiopathogenesis of epilepsy and convulsive disorders with Toll-like receptor (TLR) signal transduction being highly involved. Among TLR family members, TLR4 is an innate immune system receptor and lipopolysaccharide (LPS) sensor that has been reported to contribute to epileptogenesis by regulating neuronal excitability. Herein, we discuss available evidence on the role of TLR4 and its endogenous ligands, the high mobility group box 1 (HMGB1) protein, the heat shock proteins (HSPs) and the myeloid related protein 8 (MRP8), in epileptogenesis and post-traumatic epilepsy (PTE). Moreover, we provide an account of the promising findings of TLR4 modulation/inhibition in experimental animal models with therapeutic impact on seizures.
    Matched MeSH terms: Ligands
  12. Fulltext Synthesis and characterization of Pd(II) and Ni(II) complexes of Schiff bases and catalytic activity of Pd(II) complexes
    Amalina Mohd Tajuddin, Hadariah Bahron, Shahrul Nizam Ahmad
    Scientific Research Journal, 2015;12(2):0-0.
    MyJurnal
    Six new Pd(II) and Ni(II) metal complexes of N, O-bidentate (L1, L2) and ONNO-tetradentate (L3) Schiff base ligands have been synthesized. The compounds were characterized via various physicochemical and spectroscopic techniques namely elemental analysis (CHN), FT-IR, 1H and 13C NMR as well as magnetic susceptibility measurement. All complexes showed diamagnetism indicating that they are square planar complexes. Catalytic performance of Pd(L1)2 and Pd(L2)2 were investigated for Heck cross-coupling reaction under optimum operating parameters, monitored using GC-FID for 6 h of reaction time in inert conditions. High catalytic activities of up to 90% were observed in the presence of triethylamine as base and DMA as solvent at 100oC with 1 mmol% catalyst loading. The mechanism of catalyzed Heck reaction is proposed to go through a series of conversion of Pd(0)/Pd(II).
    Matched MeSH terms: Ligands
  13. Fulltext Synthesis of 4-(dimethylamino)pyridine propylthioacetate coated gold nanoparticles and their antibacterial and photophysical activity
    Anwar A, Khalid S, Perveen S, Ahmed S, Siddiqui R, Khan NA, et al.
    J Nanobiotechnology, 2018 Jan 29;16(1):6.
    PMID: 29378569 DOI: 10.1186/s12951-017-0332-z
    BACKGROUND: Gold nanoparticles are useful candidate for drug delivery applications and are associated with enhancement in the bioavailability of coated drugs and/or therapeutic agent. Since, heterocyclic compounds are known to exhibit antimicrobial potential against variety of pathogens, we designed this study to evaluate the antibacterial effects of gold nanoparticles conjugation with new synthesized cationic ligand; 4-Dimethyl aminopyridinium propylthioacetate (DMAP-PTA) in comparison with pure compound and antibiotic drug Pefloxacin. Antibacterial activity of DMAP-PTA coated gold nanoparticles was investigated against a fecal strain of E. coli (ATCC 8739).

    RESULTS: A new dimethyl aminopyridine based stabilizing agent named as DMAP-PTA was synthesized and used for stabilization of gold nanoparticles. Gold nanoparticles coated with DMAP-PTA abbreviated as DMAP-PTA-AuNPs were thoroughly characterized by UV-visible, FT-IR spectroscopic methods and transmission electron microscope before biological assay. DMAP-PTA, DMAP-PTA-AuNPs and Pefloxacin were examined for their antibacterial potential against E. coli, and the minimum inhibitory concentration (MIC) was determined to be 300, 200 and 50 µg/mL respectively. Gold nanoparticles conjugation was found to significantly enhance the antibacterial activity of DMAP-PTA as compared to pure compound. Moreover, effects of DMAP-PTA-AuNPs on the antibacterial potential of Pefloxacin was also evaluated by combination therapy of 1:1 mixture of DMAP-PTA-AuNPs and Pefloxacin against E. coli in a wide range of concentrations from 5 to 300 µg/mL. The MIC of Pefloxacin + DMAP-PTA-AuNPs mixture was found to be 25 µg/mL as compared to Pefloxacin alone (50 µg/mL), which clearly indicates that DMAP-PTA-AuNPs increased the potency of Pefloxacin. AFM analysis was also carried out to show morphological changes occur in bacteria before and after treatment of test samples. Furthermore, DMAP-PTA-AuNPs showed high selectivity towards Pefloxacin in spectrophotometric drug recognition studies which offers tremendous potential for analytical applications.

    CONCLUSIONS: Gold nanoparticles conjugation was shown to enhance the antibacterial efficacy of DMAP-PTA ligand, while DMAP-PTA-AuNPs also induced synergistic effects on the potency of Pefloxacin against E. coli. DMAP-PTA-AuNPs were also developed as Pefloxacin probes in recognizing the drug in blood and water samples in the presence of other drugs.

    Matched MeSH terms: Ligands
  14. Bi-heterocyclic benzamides as alkaline phosphatase inhibitors: Mechanistic comprehensions through kinetics and computational approaches
    Abbasi MA, Nazir M, Ur-Rehman A, Siddiqui SZ, Hassan M, Raza H, et al.
    Arch Pharm (Weinheim), 2019 Mar;352(3):e1800278.
    PMID: 30624805 DOI: 10.1002/ardp.201800278
    Novel bi-heterocyclic benzamides were synthesized by sequentially converting 4-(1H-indol-3-yl)butanoic acid (1) into ethyl 4-(1H-indol-3-yl)butanoate (2), 4-(1H-indol-3-yl)butanohydrazide (3), and a nucleophilic 5-[3-(1H-indol-3-yl)propyl]-1,3,4-oxadiazole-2-thiol (4). In a parallel series of reactions, various electrophiles were synthesized by reacting substituted anilines (5a-k) with 4-(chloromethyl)benzoylchloride (6) to afford 4-(chloromethyl)-N-(substituted-phenyl)benzamides (7a-k). Finally, the nucleophilic substitution reaction of 4 was carried out with newly synthesized electrophiles, 7a-k, to acquire the targeted bi-heterocyclic benzamides, 8a-k. The structural confirmation of all the synthesized compounds was done by IR, 1 H NMR, 13 C NMR, EI-MS, and CHN analysis data. The inhibitory effects of these bi-heterocyclic benzamides (8a-k) were evaluated against alkaline phosphatase, and all these molecules were identified as potent inhibitors relative to the standard used. The kinetics mechanism was ascribed by evaluating the Lineweaver-Burk plots, which revealed that compound 8b inhibited alkaline phosphatase non-competitively to form an enzyme-inhibitor complex. The inhibition constant Ki calculated from Dixon plots for this compound was 1.15 μM. The computational study was in full agreement with the experimental records and these ligands exhibited good binding energy values. These molecules also exhibited mild cytotoxicity toward red blood cell membranes when analyzed through hemolysis. So, these molecules might be deliberated as nontoxic medicinal scaffolds to render normal calcification of bones and teeth.
    Matched MeSH terms: Ligands
  15. Fulltext Synthesis, enzyme inhibitory kinetics mechanism and computational study of N-(4-methoxyphenethyl)-N-(substituted)-4-methylbenzenesulfonamides as novel therapeutic agents for Alzheimer's disease
    Abbasi MA, Hassan M, Aziz-Ur-Rehman, Siddiqui SZ, Shah SAA, Raza H, et al.
    PeerJ, 2018;6:e4962.
    PMID: 29967717 DOI: 10.7717/peerj.4962
    The present study comprises the synthesis of a new series of sulfonamides derived from 4-methoxyphenethylamine (1). The synthesis was initiated by the reaction of 1 with 4-methylbenzenesulfonyl chloride (2) in aqueous sodium carbonate solution at pH 9 to yield N-(4-methoxyphenethyl)-4-methylbenzensulfonamide (3).This parent molecule 3 was subsequently treated with various alkyl/aralkyl halides, (4a-j), using N,N-dimethylformamide (DMF) as solvent and LiH as activator to produce a series of new N-(4-methoxyphenethyl)-N-(substituted)-4-methylbenzenesulfonamides (5a-j). The structural characterization of these derivatives was carried out by spectroscopic techniques like IR, 1H-NMR, and 13C-NMR. The elemental analysis data was also coherent with spectral data of these molecules. The inhibitory effects on acetylcholinesterase and DPPH were evaluated and it was observed that N-(4-Methoxyphenethyl)-4-methyl-N-(2-propyl)benzensulfonamide (5c) showed acetylcholinesterase inhibitory activity 0.075 ± 0.001 (IC50 0.075 ± 0.001 µM) comparable to Neostigmine methylsulfate (IC50 2.038 ± 0.039 µM).The docking studies of synthesized ligands 5a-j were also carried out against acetylcholinesterase (PDBID 4PQE) to compare the binding affinities with IC50 values. The kinetic mechanism analyzed by Lineweaver-Burk plots demonstrated that compound (5c) inhibits the acetylcholinesterase competitively to form an enzyme inhibitor complex. The inhibition constants Ki calculated from Dixon plots for compound (5c) is 2.5 µM. It was also found from kinetic analysis that derivative 5c irreversible enzyme inhibitor complex. It is proposed on the basis of our investigation that title compound 5c may serve as lead structure for the design of more potent acetylcholinesterase inhibitors.
    Matched MeSH terms: Ligands
  16. Synthesis of novel N-(1,3-thiazol-2-yl)benzamide clubbed oxadiazole scaffolds: Urease inhibition, Lipinski rule and molecular docking analyses
    Athar Abbasi M, Raza H, Aziz-Ur-Rehman, Zahra Siddiqui S, Adnan Ali Shah S, Hassan M, et al.
    Bioorg Chem, 2019 03;83:63-75.
    PMID: 30342387 DOI: 10.1016/j.bioorg.2018.10.018
    Present work aimed to synthesize some unique bi-heterocyclic benzamides as lead compounds for the in vitro inhibition of urease enzyme, followed by in silico studies. These targeted benzamides were synthesized in good yields through a multi-step protocol and their structures were confirmed by IR, 1H NMR, 13C NMR, EI-MS and elemental analysis. The in vitro screening results showed that most of the ligands exhibited good inhibitory potentials against the urease. Chemo-informatics analysis envisaged that all these compounds obeyed the Lipinski's rule. Molecular docking results showed that 7h exhibited good binding energy value (-8.40 kcal/mol) and was bound within the active region of urease enzyme. From the present investigation, it was inferred that some of these potent urease inhibitors might serve as novel templates in drug designing.
    Matched MeSH terms: Ligands
  17. Fulltext Thermodynamics of semi-specific ligand recognition: the binding of dipeptides to the E.coli dipeptide binding protein DppA
    Zainol MKM, Linforth RJC, Winzor DJ, Scott DJ
    Eur Biophys J, 2021 Dec;50(8):1103-1110.
    PMID: 34611772 DOI: 10.1007/s00249-021-01572-y
    This investigation of the temperature dependence of DppA interactions with a subset of three dipeptides (AA. AF and FA) by isothermal titration calorimetry has revealed the negative heat capacity ([Formula: see text]) that is a characteristic of hydrophobic interactions. The observation of enthalpy-entropy compensation is interpreted in terms of the increased structuring of water molecules trapped in a hydrophobic environment, the enthalpic energy gain from which is automatically countered by the entropy decrease associated with consequent loss of water structure flexibility. Specificity for dipeptides stems from appropriate spacing of designated DppA aspartate and arginine residues for electrostatic interaction with the terminal amino and carboxyl groups of a dipeptide, after which the binding pocket closes to become completely isolated from the aqueous environment. Any differences in chemical reactivity of the dipeptide sidechains are thereby modulated by their occurrence in a hydrophobic environment where changes in the structural state of entrapped water molecules give rise to the phenomenon of enthalpy-entropy compensation. The consequent minimization of differences in the value of ΔG0 for all DppA-dipeptide interactions thus provides thermodynamic insight into the biological role of DppA as a transporter of all dipeptides across the periplasmic membrane.
    Matched MeSH terms: Ligands
  18. Elucidating isoniazid resistance using molecular modeling
    Wahab HA, Choong YS, Ibrahim P, Sadikun A, Scior T
    J Chem Inf Model, 2009 Jan;49(1):97-107.
    PMID: 19067649 DOI: 10.1021/ci8001342
    The continuing rise in tuberculosis incidence and the problem of drug resistance strains have prompted the research on new drug candidates and the mechanism of drug resistance. Molecular docking and molecular dynamics simulation (MD) were performed to study the binding of isoniazid onto the active site of Mycobacterium tuberculosis enoyl-acyl carrier protein reductase (InhA) in an attempt to address the mycobacterial resistance against isoniazid. Results show that isonicotinic acyl-NADH (INADH) has an extremely high binding affinity toward the wild type InhA by forming stronger interactions compared to the parent drug (isoniazid) (INH). Due to the increase of hydrophobicity and reduction in the side chain's volume of A94 of mutant type InhA, both INADH and the mutated protein become more mobile. Due to this reason, the molecular interactions of INADH with mutant type are weaker than that observed with the wild type. However, the reduced interaction caused by the fluctuation of INADH and the mutant protein only inflected minor resistance in the mutant strain as inferred from free energy calculation. MD results also showed there exists a water-mediated hydrogen bond between INADH and InhA. However, the bridged water molecule is only present in the INADH-wild type complex, reflecting the putative role of the water molecule in the binding of INADH to the wild type protein. The results support the assumption that the conversion of prodrug isoniazid into its active form INADH is mediated by KatG as a necessary step prior to target binding on InhA. Our findings also contribute to a better understanding of INH resistance in mutant type.
    Matched MeSH terms: Ligands
  19. Fulltext Common variants of chemokine receptor gene CXCR3 and its ligands CXCL10 and CXCL11 associated with vascular permeability of dengue infection in peninsular Malaysia
    Hoh BP, Umi-Shakina H, Zuraihan Z, Zaiharina MZ, Rafidah-Hanim S, Mahiran M, et al.
    Hum Immunol, 2015 Jun;76(6):421-6.
    PMID: 25858769 DOI: 10.1016/j.humimm.2015.03.019
    Dengue causes significantly more human disease than any other arboviruses. It causes a spectrum of illness, ranging from mild self-limited fever, to severe and fatal dengue hemorrhagic fever, as evidenced by vascular leakage and multifactorial hemostatic abnormalities. There is no specific treatment available till date. Evidence shows that chemokines CXCL10, CXCL11 and their receptor CXCR3 are involved in severity of dengue, but their genetic association with the susceptibility of vascular leakage during dengue infection has not been reported. We genotyped 14 common variants of these candidate genes in 176 patients infected with dengue. rs4859584 and rs8878 (CXCL10) were significantly associated with vascular permeability of dengue infection (P<0.05); while variants of CXCL11 showed moderate significance of association (P=0.0527). Haplotype blocks were constructed for genes CXCL10 and CXCL11 (5 and 7 common variants respectively). Haplotype association tests performed revealed that, "CCCCA" of gene CXCL10 and "AGTTTAC" of CXCL11 were found to be significantly associated with vascular leakage (P=0.0154 and 0.0366 respectively). In summary, our association study further strengthens the evidence of the involvement of CXCL10 and CXCL11 in the pathogenesis of dengue infection.
    Matched MeSH terms: Ligands
  20. Ion-Imprinted Polymer for Selective Separation of Cerium(III) Ions from Rare Earth Mixture
    Rahman ML, Puah PY, Sarjadi MS, Arshad SE, Musta B, Sarkar SM
    J Nanosci Nanotechnol, 2019 09 01;19(9):5796-5802.
    PMID: 30961741 DOI: 10.1166/jnn.2019.16538
    Ion-imprinting polymers (IIPs) materials draw the great recognition because of the powerful selectivity to the desired metal ions. Therefore, the ion-imprinting polymer (Ce-IIP) was prepared by using cerium metal with amidoxime ligand as the complexing agent, in addition ethylene glycol dimethacrylate (EGDMA) and 2,2-azobisisobutyronitrile (AIBN) are crosslinking agent and free radical initiator, respectively. Aqueous HCl was applied to leach the cerium ions from the imprinted polymer for the creation of cavities of template, which is utilized for further cerium ions adsorption with high selectivity. The Ce-IIP was characterized by using ICP-MS, FE-SEM and also solid state analysis by UV-vis NIR spectroscopy. FT-IR study confirmed the complexation of the Ce-IIP was successful. The optimum pH was found to be 6 and the highest adsorption capacity was estimated about 145 mg g-1. Thus, the prepared Ce-IIP gave very good selectivity to cerium ions in the presence of lanthanide ions and also Ce-IIP can be reused 10 times without a substantial loss in adsorption capacity.
    Matched MeSH terms: Ligands
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