Displaying publications 161 - 180 of 262 in total

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  1. Haezam FN, Awang N, Kamaludin NF, Mohamad R
    Saudi J Biol Sci, 2021 May;28(5):3160-3168.
    PMID: 34025187 DOI: 10.1016/j.sjbs.2021.02.060
    Context: Diphenyltin(IV) diallyldithiocarbamate compound (Compound 1) and triphenyltin(IV) diallyldithiocarbamate compound (Compound 2) are two newly synthesised compounds of organotin(IV) with diallyldithiocarbamate ligands.

    Objective: To assess the cytotoxic effects of two synthesised compounds against HT-29 human colon adenocarcinoma cells and human CCD-18Co normal colon cells.

    Materials and methods: Two successfully synthesised compounds were characterised using elemental (carbon, hydrogen, nitrogen, and sulphur) analysis, Fourier-Transform Infrared (FTIR), and 1H, 13C 119Sn Nucleus Magnetic Resonance (NMR) spectroscopies. The single-crystal structure of both compounds was determined by X-ray single-crystal analysis. The cytotoxicity of the compounds was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazholium bromide (MTT) assay upon 24 h of treatment. While the mode of cell death was determined based on the externalisation of phosphatidylserine using a flow cytometer.

    Results: The elemental analysis data of the two compounds showed an agreement with the suggested formula of (C6H5)2Sn[S2CN(C3H5)2]2 for Compound 1 and (C6H5)3Sn[S2CN(C3H5)2] for Compound 2. The two major peaks of infrared absorbance, i.e., ν(C = N) and ν(C = S) were detected at the range of 1475-1479 cm-1 and 972-977 cm-1, respectively. The chemical shift of carbon in NCS2 group for Compound 1 and 2 were found at 200.82 and 197.79 ppm. The crystal structure of Compound 1 showed that it is six coordinated and crystallised in monoclinic, P21/c space group. While the crystal structure of Compound 2 is five coordinated and crystallised in monoclinic, P21/c space group. The cytotoxicity (IC50) of the two compounds against HT-29 cell were 2.36 μM and 0.39 μM. Meanwhile, the percentage of cell death modes between 60% and 75% for compound 1 and compound 2 were mainly due to apoptosis, suggesting that both compounds induced growth arrest.

    Conclusion: Our study concluded that the synthesised compounds showed potent cytotoxicity towards HT-29 cell, with the triphenyltin(IV) compound showing the highest effect compared to diphenyltin(IV).

    Matched MeSH terms: Ligands
  2. Ravichandran R, Ridzwan NFW, Mohamad SB
    J Biomol Struct Dyn, 2020 Dec 31.
    PMID: 33382017 DOI: 10.1080/07391102.2020.1867641
    The disease Tuberculosis (TB) is caused by a bacterium called Mycobacterium tuberculosis (Mtb). The bacterial cell-wall consists of peptidoglycan layer maintains the cellular integrity and cell viability. The main problem resides in the cell cycle of Mycobacterium tuberculosis in its quiescent form which is not targeted by any drugs hence there is an immediate need for new antibiotics to target the cell wall. The current study deals with the dTDP-4-dehydrorahmnose reductase (RmlD) which is the final enzyme in the series of cell-wall proteins of Mtb. The RmlD is a part of Carbohydrate biosynthesis has been considered as a good drug target for the novel class of antibiotics. Our study begins with the protein structure prediction, Homology studies were conducted using the Phyre2 web server. The structure is then refined and subjected to molecular dynamics simulations for 50 ns using GROMACS. The clustering analysis has been carried out and generated 41 clusters with 2 Å as the cut-off. Blind docking virtual screening was performed against RmlD protein using the Super Natural-II database with AutoDock4.0. its results helped to screen top ligands based on best binding energies. In both dockings, there are some common residues in which the ligands are interacting and forming the Hydrogen bonds such as Asp-105, Val-158, Thr-160, Gly-161, Arg-224, Arg-256. The ligand-567 giving the best results by being in the top-3 of all the clusters in both blind docking as well as the active-site docking. Hence ligand-567 can be a potential inhibitor of RmlD which can further inhibit the cell-wall synthesis of Mycobacterium tuberculosis.Communicated by Ramaswamy H. Sarma.
    Matched MeSH terms: Ligands
  3. 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
  4. Khan SU, Ahemad N, Chuah LH, Naidu R, Htar TT
    J Biomol Struct Dyn, 2020 Oct 15.
    PMID: 33054574 DOI: 10.1080/07391102.2020.1830853
    Cancer ranks in second place among the cause of death worldwide. Cancer progress in multiple stages of carcinogenesis and metastasis programs through complex pathways. Sex hormones and their receptors are the major factors in promoting cancer progression. Among them, G protein-coupled estrogen receptor-1 (GPER) has shown to mediate cellular signaling pathways and cancer cell proliferation. However, the lack of GPER protein structure limited the search for new modulators. In this study, we curated an extensive database of natural products to discover new potential GPER modulators. We used a combination of virtual screening techniques to generate a homology model of GPER and subsequently used that for the screening of 30,926 natural products from a public database to identify potential active modulators of GPER. The best hits were further screened through the ADMET filter and confirmed by docking analysis. Moreover, molecular dynamics simulations of best hits were also carried out to assess the stability of the ligand-GPER complex. This study predicted several potential GPER modulators with novel scaffolds that could be further investigated and used as the core for the development of novel GPER modulators.Communicated by Ramaswamy H. Sarma.
    Matched MeSH terms: Ligands
  5. Rahman ML, Wong ZJ, Sarjadi MS, Joseph CG, Arshad SE, Musta B, et al.
    Polymers (Basel), 2021 May 06;13(9).
    PMID: 34066308 DOI: 10.3390/polym13091486
    Toxic metals in the industrial wastewaters have been liable for drastic pollution hence a powerful and economical treatment technology is needed for water purification. For this reason, some pure cellulosic materials were derived from waste fiber to obtain an economical adsorbent for wastewater treatment. Conversion of cellulose into grafting materials such as poly(methyl acrylate)-grafted cellulose was performed by free radical grafting process. Consequently, poly(hydroxamic acid) ligand was produced from the grafted cellulose. The intermediate products and poly(hydroxamic acid) ligand were analyzed by FT-IR, FE-SEM, TEM, EDX, and XPS spectroscopy. The adsorption capacity (qe) of some toxic metals ions by the polymer ligand was found to be excellent, e.g., copper capacity (qe) was 346.7 mg·g-1 at pH 6. On the other hand, several metal ions such as cobalt chromium and nickel also demonstrated noteworthy sorption capacity at pH 6. The adsorption mechanism obeyed the pseudo second-order rate kinetic model due to the satisfactory correlated experimental sorption values (qe). Langmuir model isotherm study showed the significant correlation coefficient with all metal ions (R2 > 0.99), indicating that the single or monolayer adsorption was the dominant mode on the surface of the adsorbent. This polymer ligand showed good properties on reusability. The result shows that the adsorbent may be recycled for 6 cycles without any dropping of starting sorption capabilities. This polymeric ligand showed outstanding toxic metals removal magnitude, up to 90-99% of toxic metal ions can be removed from industrial wastewater.
    Matched MeSH terms: Ligands
  6. Angelopoulou E, Paudel YN, Piperi C
    ACS Chem Neurosci, 2020 03 04;11(5):663-673.
    PMID: 32017530 DOI: 10.1021/acschemneuro.9b00678
    Myasthenia gravis (MG) is an autoimmune T cell-dependent B cell-mediated disorder of the neuromuscular junction (NMJ) characterized by fluctuating skeletal muscle weakness, most commonly attributed to pathogenic autoantibodies against postsynaptic nicotinic acetylcholine receptors (AChRs). Although MG pathogenesis is well-documented, there are no objective biomarkers that could effectively correlate with disease severity or MG clinical subtypes, and current treatment approaches are often ineffective. The receptor for advanced glycation end products (RAGE) is a multiligand cell-bound receptor highly implicated in proinflammatory responses and autoimmunity. Preclinical evidence demonstrates that RAGE and its ligand S100B are upregulated in rat models of experimental autoimmune myasthenia gravis (EAMG). S100B-mediated RAGE activation has been shown to exacerbate EAMG, by enhancing T cell proinflammatory responses, aggravating T helper (Th) subset imbalance, increasing AChR-specific T cell proliferative capacity, and promoting the production of antibodies against AChRs from the spleen. Soluble sRAGE and esRAGE, acting as decoys of RAGE ligands, are found to be significantly reduced in MG patients. Moreover, MG has been associated with increased serum levels of S100A12, S100B and HMGB1. Several studies have shown that the presence of thymic abnormalities, the onset age of MG, and the duration of the disease may affect the levels of these proteins in MG patients. Herein, we discuss the emerging role of RAGE and its ligands in MG immunopathogenesis, their clinical significance as promising biomarkers, as well as the potential therapeutic implications of targeting RAGE signaling in MG treatment.
    Matched MeSH terms: Ligands
  7. Shreaz S, Shiekh RA, Raja V, Wani WA, Behbehani JM
    Chem Biol Interact, 2016 Mar 05;247:64-74.
    PMID: 26806515 DOI: 10.1016/j.cbi.2016.01.015
    In this study, we have used aldehyde function of cinnamaldehyde to synthesize N, N'-Bis (cinnamaldehyde) ethylenediimine [C20H20N2] and Co(II) complex of the type [Co(C40H40N4)Cl2]. The structures of the synthesized compounds were determined on the basis of physiochemical analysis and spectroscopic data ((1)H NMR, FTIR, UV-visible and mass spectra) along with molar conductivity measurements. Anticandidal activity of cinnamaldehyde its ligand [L] and Co(II) complex was investigated by determining MIC80, time-kill kinetics, disc diffusion assay and ergosterol extraction and estimation assay. Ligand [L] and Co(II) complex are found to be 4.55 and 21.0 folds more efficient than cinnamaldehyde in a liquid medium. MIC80 of Co(II) complex correlated well with ergosterol inhibition suggesting ergosterol biosynthesis to be the primary site of action. In comparison to fluconazole, the test compounds showed limited toxicity against H9c2 rat cardiac myoblasts. In confocal microscopy propidium iodide (PI) penetrates the yeast cells when treated with MIC of metal complex, indicating a disruption of cell membrane that results in imbibition of dye. TEM analysis of metal complex treated cells exhibited notable alterations or damage to the cell membrane and the cell wall. The structural disorganization within the cell cytoplasm was noted. It was concluded that fungicidal activity of Co(II) complex originated from loss of membrane integrity and a decrease in ergosterol content is only one consequence of this.
    Matched MeSH terms: Ligands
  8. Al-Qattan MN, Mordi MN, Mansor SM
    Comput Biol Chem, 2016 10;64:237-249.
    PMID: 27475235 DOI: 10.1016/j.compbiolchem.2016.07.007
    BACKGROUND: Glutathione-s-transferases (GSTs) are enzymes that principally catalyze the conjugation of electrophilic compounds to the endogenous nucleophilic glutathione substrate, besides, they have other non-catalytic functions. The Plasmodium falciparum genome encodes a single isoform of GST (PfGST) which is involved in buffering the toxic heme, thus considered a potential anti-malarial target. In mammals several classes of GSTs are available, each of various isoforms. The human (human GST Pi-1 or hGSTP1) and mouse (murine GST Mu-1 or mGSTM1) GST isoforms control cellular apoptosis by interaction with signaling proteins, thus considered as potential anti-cancer targets. In the course of GSTs inhibitors development, the models of ligands interactions with GSTs are used to guide rational molecular modification. In the absence of X-ray crystallographic data, enzyme kinetics and molecular docking experiments can aid in addressing ligands binding modes to the enzymes.

    METHODS: Kinetic studies were used to investigate the interactions between the three GSTs and each of glutathione, 1-chloro-2,4-dinitrobenzene, cibacron blue, ethacrynic acid, S-hexyl glutathione, hemin and protoporphyrin IX. Since hemin displacement is intended for PfGST inhibitors, the interactions between hemin and other ligands at PfGST binding sites were studied kinetically. Computationally determined binding modes and energies were interlinked with the kinetic results to resolve enzymes-ligands interaction models at atomic level.

    RESULTS: The results showed that hemin and cibacron blue have different binding modes in the three GSTs. Hemin has two binding sites (A and B) with two binding modes at site-A depending on presence of GSH. None of the ligands were able to compete hemin binding to PfGST except ethacrynic acid. Besides bind differently in GSTs, the isolated anthraquinone moiety of cibacron blue is not maintaining sufficient interactions with GSTs to be used as a lead. Similarly, the ethacrynic acid uses water bridges to mediate interactions with GSTs and at least the conjugated form of EA is the true hemin inhibitor, thus EA may not be a suitable lead.

    CONCLUSIONS: Glutathione analogues with bulky substitution at thiol of cysteine moiety or at γ-amino group of γ-glutamine moiety may be the most suitable to provide GST inhibitors with hemin competition.

    Matched MeSH terms: Ligands
  9. Saswati, Adão P, Majumder S, Dash SP, Roy S, Kuznetsov ML, et al.
    Dalton Trans, 2018 Aug 21;47(33):11358-11374.
    PMID: 30059099 DOI: 10.1039/c8dt01668b
    The synthesis and characterization of an oxidovanadium(iv) [VIVO(L)(acac)] (1) and of two dioxidovanadium(v) [VVO2(L')] (2) and [VVO2(L)] (2a) complexes of the Schiff base formed from the reaction of 4-(p-fluorophenyl) thiosemicarbazone with pyridine-2-aldehyde (HL) are described. The oxidovanadium(iv) species [VIVO(L)(acac)] (1) was synthesized by the reaction of VIVO(acac)2 with the thiosemicarbazone HL in refluxing ethanol. The recrystallization of [VIVO(L)(acac)] (1) in DMF, CH3CN or EtOH gave the same product i.e. the dioxidovanadium(v) complex [VVO2(L)] (2a); however, upon recrystallization of 1 in DMSO a distinct compound [VVO2(L')] (2) was formed, wherein the original ligand L- is transformed to a rearranged one, L'-. In the presence of DMSO the ligand in complex 1 is found to undergo methylation at the carbon centre attached to imine nitrogen (aldimine) and transformed to the corresponding VVO2-species through in situ reaction. The synthesized HL and the metal complexes were characterized by elemental analysis, IR, UV-Vis, NMR and EPR spectroscopy. The molecular structure of [VVO2(L')] (2) was determined by single crystal X-ray crystallography. The methylation of various other ligands and complexes prepared from different vanadium precursors under similar reaction conditions was also attempted and it was confirmed that the imine methylation observed is both ligand and metal precursor specific. Complexes 1 and 2 show in vitro insulin-like activity against insulin responsive L6 myoblast cells, higher than VIVO(acac)2, with complex 1 being more potent. In addition, the in vitro cytotoxicity studies of HL, and of complexes 1 and 2 against the MCF-7 and Vero cell lines were also done. The ligand is not cytotoxic and complex 2 is significantly more cytotoxic than 1. DAPI staining experiments indicate that an increase in the time of incubation and an increase of concentration of the complexes lead to the increase in cell death.
    Matched MeSH terms: Ligands
  10. Al-Dabbagh MM, Salim N, Himmat M, Ahmed A, Saeed F
    J Comput Aided Mol Des, 2017 Apr;31(4):365-378.
    PMID: 28220440 DOI: 10.1007/s10822-016-0003-4
    Chemical libraries contain thousands of compounds that need screening, which increases the need for computational methods that can rank or prioritize compounds. The tools of virtual screening are widely exploited to enhance the cost effectiveness of lead drug discovery programs by ranking chemical compounds databases in decreasing probability of biological activity based upon probability ranking principle (PRP). In this paper, we developed a novel ranking approach for molecular compounds inspired by quantum mechanics, called quantum probability ranking principle (QPRP). The QPRP ranking criteria would make an attempt to draw an analogy between the physical experiment and molecular structure ranking process for 2D fingerprints in ligand based virtual screening (LBVS). The development of QPRP criteria in LBVS has employed the concepts of quantum at three different levels, firstly at representation level, this model makes an effort to develop a new framework of molecular representation by connecting the molecular compounds with mathematical quantum space. Secondly, estimate the similarity between chemical libraries and references based on quantum-based similarity searching method. Finally, rank the molecules using QPRP approach. Simulated virtual screening experiments with MDL drug data report (MDDR) data sets showed that QPRP outperformed the classical ranking principle (PRP) for molecular chemical compounds.
    Matched MeSH terms: Ligands
  11. Chah, C.K., Ravoof, T.B.S.A., Veerakumarasivam, A.
    MyJurnal
    A novel nitrogen-sulphur macrocyclic Schiff base, 4,11,20,27-tetrathioxo3,12,19,28-tetrathia-5,6,9,10,21,22,25,26-octaazatricyclo[28.2.2.214,17]hexatriaconta 1(33),6,8,14(36),15,17(35),22,24,30(34),31-decaene-2,13,18,29-tetraone (TGSB) derived from terephthaloyl-bis-dithiocarbazate (TDTC) and glyoxal (ethane-1,2-dione) is synthesised via condensation. Metal complexes are formed by reacting the Schiff base with various metal salts such as Ru(III), Mo(V), Cd(II), Zn(II) and Cu(II). The complexes are expected to have a general formula of M2L or M3L with a square planar or square pyramidal geometry. These compounds were characterised by various physicochemical and spectroscopic techniques. From the data, it is concluded that the azomethine nitrogen atom and the thiolate sulphur atom from the ligand are bonded to the metal ion. In the IR spectra of the complexes, the presence of the C=N band in the region of 1600 cm-1 indicates the successful formation of the Schiff base. The structures of the Schiff base and metal complexes are confirmed via FT-IR, GC-MS and NMR spectroscopic analysis. The magnetic susceptibility measurements, electronic spectral data and molar conductivity analysis support the desired geometry of the complexes. The Schiff base and its metal complexes are evaluated for their biological activities against the invasive human bladder carcinoma cell line (EJ-28) and the minimuminvasive human bladder carcinoma cell line (RT-112). The RuTGSB and CdTGSB complexes showed selective activity against RT-112.
    Matched MeSH terms: Ligands
  12. Alhajj N, Chee CF, Wong TW, Rahman NA, Abu Kasim NH, Colombo P
    Expert Opin Drug Deliv, 2018 12;15(12):1223-1247.
    PMID: 30422017 DOI: 10.1080/17425247.2018.1547280
    INTRODUCTION: Pulmonary drug delivery is organ-specific and benefits local drug action for lung cancer. The use of nanotechnology and targeting ligand enables cellular-specific drug action. Combination approaches increase therapeutic efficacy and reduce adverse effects of cancer chemotherapeutics that have narrow therapeutic index window and high cytotoxicity levels. The current progress of inhaled cancer chemotherapeutics has not been examined with respect to targeting strategy and clinical application potential.

    AREAS COVERED: This review examines the state of the art in passive (processing and formulation) and active (targeting ligand and receptor binding) technologies in association with the use of nanocarrier to combat lung cancer. It highlights routes to equip nanocarrier with targeting ligands as a function of the chemistry of participating biomolecules and challenges in inhalational nanoproduct development and clinical applications. Both research and review articles were examined using the Scopus, Elsevier, Web of Science, Chemical Abstracts, Medline, CASREACT, CHEMCATS, and CHEMLIST database with the majority of information retrieved between those of 2000-2018.

    EXPERT COMMENTARY: The therapeutic efficacy of targeting ligand-decorated nanocarriers needs to be demonstrated in vivo in the form of finished inhalational products. Their inhalation efficiency and medical responses require further examination. Clinical application of inhaled nanocancer chemotherapeutics is premature.

    Matched MeSH terms: Ligands
  13. Ting T, Crouse K, Ahmad H
    Sains Malaysiana, 2015;44:619-628.
    Three novel ruthenium(II) complexes of the general formula [Ru(II)(bpy)2
    L]2+ were synthesized, where L =
    1,10-phenanthroline derivatives of position 2 imidazole having 3,4-didecyloxy-phenyl (ddip), 3,4-ditetradecyloxy-phenyl
    (dtip) and 3,4-dihexadecyloxy-phenyl (dhip). All complexes were characterized by elemental analysis, 1
    H-NMR and ESI-MS.
    Their photophysical properties have also been studied by UV-visible spectroscopy and fluorescence spectroscopy. The
    complexes exhibit Ru(II) metal centered emission at approximately 610 nm in acetonitrile solution at room temperature. DNA
    binding studies were carried out by UV-visible titration, luminescence titration and viscosity studies. The results indicated
    that [Ru(bpy)2
    (ddip)]2+ binds to CT-DNA by partial intercalation mode, while [Ru(bpy)2
    (dtip)]2+ and [Ru(bpy)2
    (dhip)]2+
    bind intercalatively via extended ligands.
    Matched MeSH terms: Ligands
  14. Diosdado A, Simón F, Morchón R, González-Miguel J
    Parasit Vectors, 2020 Apr 20;13(1):203.
    PMID: 32312291 DOI: 10.1186/s13071-020-04067-5
    BACKGROUND: Ascaris roundworms are the parasitic nematodes responsible for causing human and porcine ascariasis. Whereas A. lumbricoides is the most common soil-transmitted helminth infecting humans in the world, A. suum causes important economic losses in the porcine industry. The latter has been proposed as a model for the study of A. lumbricoides since both species are closely related. The third larval stage of these parasites carries out an intriguing and complex hepatopulmonary route through the bloodstream of its hosts. This allows the interaction between larvae and the physiological mechanisms of the hosts circulatory system, such as the fibrinolytic system. Parasite migration has been widely linked to the activation of this system by pathogens that are able to bind plasminogen and enhance plasmin generation. Therefore, the aim of this study was to examine the interaction between the infective third larval stage of A. suum and the host fibrinolytic system as a model of the host-Ascaris spp. relationships.

    METHODS: Infective larvae were obtained after incubating and hatching fertile eggs of A. suum in order to extract their cuticle and excretory/secretory antigens. The ability of both extracts to bind and activate plasminogen, as well as promote plasmin generation were assayed by ELISA and western blot. The location of plasminogen binding on the larval surface was revealed by immunofluorescence. The plasminogen-binding proteins from both antigenic extracts were revealed by two-dimensional electrophoresis and plasminogen-ligand blotting, and identified by mass spectrometry.

    RESULTS: Cuticle and excretory/secretory antigens from infective larvae of A. suum were able to bind plasminogen and promote plasmin generation in the presence of plasminogen activators. Plasminogen binding was located on the larval surface. Twelve plasminogen-binding proteins were identified in both antigenic extracts.

    CONCLUSIONS: To the best of our knowledge, the present results showed for the first time, the pro-fibrinolytic potential of infective larvae of Ascaris spp., which suggests a novel parasite survival mechanism by facilitating the migration through host tissues.

    Matched MeSH terms: Ligands
  15. 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
  16. Siar CH, Kawakami T, Buery RR, Nakano K, Tomida M, Tsujigiwa H, et al.
    Eur J Med Res, 2011 Nov 10;16(11):501-6.
    PMID: 22027644
    Notch signaling is an evolutionarily conserved mechanism that enables adjacent cells to adopt different fates. Ghost cells (GCs) are anucleate cells with homogeneous pale eosinophilic cytoplasm and very pale to clear central areas (previous nucleus sites). Although GCs are present in a variety of odontogenic lesions notably the calcifying cystic odontogenic tumor (CCOT), their nature and process of formation remains elusive. The aim of this study was to investigate the role of Notch signaling in the cell fate specification of GCs in CCOT. Immunohistochemical staining for four Notch receptors (Notch1, Notch2, Notch3 and Notch4) and three ligands (Jagged1, Jagged2 and Delta1) was performed on archival tissues of five CCOT cases. Level of positivity was quantified as negative (0), mild (+), moderate (2+) and strong (3+). Results revealed that GCs demonstrated overexpression for Notch1 and Jagged1 suggesting that Notch1-Jagged1 signaling might serve as the main transduction mechanism in cell fate decision for GCs in CCOT. Protein localizations were largely membranous and/or cytoplasmic. Mineralized GCs also stained positive implicating that the calcification process might be associated with upregulation of these molecules. The other Notch receptors and ligands were weak to absent in GCs and tumoral epithelium. Stromal endothelium and fibroblasts were stained variably positive.
    Matched MeSH terms: Ligands
  17. Saadi S, Saari N, Abdulkarim MS, Ghazali HM, Anwar F
    J Control Release, 2018 03 28;274:93-101.
    PMID: 29031897 DOI: 10.1016/j.jconrel.2017.10.011
    Cell impurities are an emerging nucleating molecular barriers having the capability in disordering the metabolic chain reactions of proteolysis, glycolysis and lipolysis. Their massive effects induced by copolymer crystal growth in compaction with metal and mineral transients are extended as well as in damaging DNA and mRNA structure motif and other molecular assembly e.g. histones structure unites. Their polycrystalline packing modes, polydispersity and their tendency to surface and interface adhesion prompted us in structuring scaffold biomaterials enriched with biopeptides, layered by phospho-glycerides ester-forms. The interface tension of the formed map is flexible and dependent to the surface exposure and its collapse modes to the surrounding molecular ligands. Thus, the attempts in increasing surface exposure e.g. the viscoelastic of structured lipopeptides and types of formed network structures interplays an extra- conjugating biomolecules having a least cytotoxicity effects to cells constituents. Disulfides molecules are selected to be the key regulatory element in rejoining both lipidic and proteic moieties by disordering atoms status via chemical ionization using organic catalyst. The insertion of methionine based peptidic chain at the lateral surfaces of scaffold biomaterials enhances the electron-meta-static motions by raising a molecular disordering status at distinct regions of the map e.g. epimerization into a nonpolar side that helps the chemical conjunction of disulfide groups with the esterified phosphoglycerides mono-layers. These effects in turn are accomplished by the formation of meso-sphere nonpolar- vesicles. The oxidation of disulfide group would alter the ordering of initial molecules by raising a newly molecular disorders to the map with high polarity to surface regions. In the same time indicates a continuation in the crystallization growth factor via a low chemical lesions between the impurities and a supersaturation in the intra-atomic distances with maximum cross linking to the deformed ligand with scaffold biomaterials.
    Matched MeSH terms: Ligands
  18. Radhakrishnan, N., Lam, K. W., Norhaizan, M. E.
    MyJurnal
    Carica papaya (papaya) fruits are available throughout the world and it is well accepted as food or as a quasi-drug. Aqueous papaya leaves extract have been used as treatment for dengue fever. This prompted us to carry out the docking study on these nine selected ligands (phyto-constituents of papaya) which are carpaine, dehydrocarpaine I and II, cardenolide, p-coumaric acid, chlorogenic acid, caricaxanthin, violaxanthin and zeaxanthin. These phytoconstituents were evaluated on the docking behaviour of dengue serotype 3 RNA-dependent RNA polymerase (RdRp); influenza A (H1N9) virus neuraminidase (NA); chikungunya virus glycoprotein (E3-E2-E1) and chikungunya virus non-structural protein2 (nsP2) protease using Discovery Studio Version 3.1. In addition, molecular physicochemical, drug-likeness, ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) and TOPKAT (Toxicity Prediction by Komputer Assisted Technology) analyses were done. The molecular physicochemical analysis revealed that cardenolide and p-coumaric acid (2 ligands) complied with Lipinski’s rule of five. Dehydrocarpaine II, cardenolide, caricaxanthin, violaxanthin and zeaxanthin all the five ligands were predicted to have plasma protein binding (PPB) effect. Docking studies and binding free energy calculations revealed that p-coumaric acid exhibited very least binding energy irrespective of its target protein. Hence, the results of this present study exhibited the potential of these nine ligands as antiviral agent.
    Matched MeSH terms: Ligands
  19. Jusoh N, Zainal H, Abdul Hamid AA, Bunnori NM, Abd Halim KB, Abd Hamid S
    J Mol Model, 2018 Mar 15;24(4):93.
    PMID: 29546582 DOI: 10.1007/s00894-018-3619-6
    Recent outbreaks of highly pathogenic influenza strains have highlighted the need to develop new anti-influenza drugs. Here, we report an in silico study of carvone derivatives to analyze their binding modes with neuraminidase (NA) active sites. Two proposed carvone analogues, CV(A) and CV(B), with 36 designed ligands were predicted to inhibit NA (PDB ID: 3TI6) using molecular docking. The design is based on structural resemblance with the commercial inhibitor, oseltamivir (OTV), ligand polarity, and amino acid residues in the NA active sites. Docking simulations revealed that ligand A18 has the lowest energy binding (∆Gbind) value of -8.30 kcal mol-1, comparable to OTV with ∆Gbind of -8.72 kcal mol-1. A18 formed seven hydrogen bonds (H-bonds) at residues Arg292, Arg371, Asp151, Trp178, Glu227, and Tyr406, while eight H-bonds were formed by OTV with amino acids Arg118, Arg292, Arg371, Glu119, Asp151, and Arg152. Molecular dynamics (MD) simulation was conducted to compare the stability between ligand A18 and OTV with NA. Our simulation study showed that the A18-NA complex is as stable as the OTV-NA complex during the MD simulation of 50 ns through the analysis of RMSD, RMSF, total energy, hydrogen bonding, and MM/PBSA free energy calculations.
    Matched MeSH terms: Ligands
  20. Wong SHM, Fang CM, Loh HS, Ngai SC
    Anticancer Agents Med Chem, 2023;23(7):817-831.
    PMID: 36380402 DOI: 10.2174/1871520623666221114095733
    AIMS: The aim of this study was to sensitize the resistant breast adenocarcinoma cells towards Tumour Necrosis Factor-related Apoptosis-inducing Ligand (TRAIL)-induced apoptosis.

    BACKGROUND: Breast cancer is a heterogeneous disease involving complex mechanisms. TRAIL is a potential anticancer candidate for targeted treatment due to its selective killing effects on neoplastic cells. Nonetheless, resistance occurs in many cancers either intrinsically or after multiple treatments.

    OBJECTIVE: Therefore, this research investigated whether the combination of Trichostatin A (TSA) and Zebularine (Zeb) (TZ) followed by TRAIL (TZT) could sensitize the human breast adenocarcinoma cells towards apoptosis.

    METHODS: The breast adenocarcinoma cells, MDA-MB-231, MCF-7 and E-MDA-MB-231 (E-cadherin re-expressed MDA-MB-231) were treated with TSA, Zeb, TZ, TRAIL and TZT. The cells were subjected to hematoxylin and eosin (H & E) staining and FITC-Annexin V/Propidium Iodide apoptosis detection prior to proteome profiling.

    RESULTS: Based on morphological observation, apoptosis was induced in all cells treated with all treatment regimens though it was more evident for the TZT-treated cells. In the apoptosis detection analysis, TZ increased early apoptosis significantly in MDA-MB-231 and MCF-7 while TRAIL induced late apoptosis significantly in E-MDA-MB-231. Based on the proteome profiling on MDA-MB-231, TRAIL R2 and Fas expression was increased. For E-MDA-MB- 231, down-regulation of catalase, paraoxonase-2 (PON2), clusterin, an inhibitor of apoptosis proteins (IAPs) and cell stress proteins validated the notion that E-cadherin re-expression enhances TZT anti-cancer efficacy. Similar trend was observed in MCF-7 whereby TZT treatment down-regulated the anti-apoptotic catalase and PON2, increased the proapoptotic, B cell lymphoma 2 (Bcl-2)-associated agonist of cell death (Bad) and Bcl-2-associated X (Bax), second mitochondria-derived activator of caspase (SMAC) and HtrA serine peptidase 2 (HTRA2) as well as TRAIL receptors (TRAIL R1 and TRAIL R2).

    CONCLUSION: TZ treatment serves as an efficient treatment regimen for MDA-MB-231 and MCF-7, while TRAIL serves as a better treatment option for E-MDA-MB-231. Therefore, future studies on E-cadherin's positive regulatory role in TRAIL-induced apoptosis are warranted.

    Matched MeSH terms: Ligands
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