Репозиторий Университета

© 2019 The Author(s) A method of 4-fluoro-3-(morpholinosulfonyl)benzo[b]thiophene-2-carboxylate synthesis has been developed and the electronic and spatial structure of a new biologically active molecule has been studied both theoretically and experimentally. The title compound was crystallized from acetonitrile and the single crystal X-ray analysis has revealed that it exists in a monoclinic P21/c space group, with one molecule in the asymmetric part of the unit cell. Hirshfeld surface analysis was used to study intermolecular interactions in the crystal. Molecular docking study evaluates the investigated compound as a new potential inhibitor of hepatitis B. Testing for anti-hepatitis B virus activity has shown that this substance demonstrates in vitro nanomolar inhibitory activity against HBV. Organic chemistry; Theoretical chemistry; Pharmaceutical chemistry, Hepatitis B; HBV; Pharmaceutical crystals; 4-Fluoro-3-(morpholinosulfonyl)benzo[b]thiophene-2-carboxylate; Benzothiophene; Hydrogen bond; Hirshfeld surface analysis; Molecular docking study

© 2019 Elsevier Masson SAS In order to expand the arsenal of biologically active substances of anticonvulsive action by the interaction of 2-(2,4-dioxo-1,4-dihydroquinazolin-3(2H)-yl)acetic acid with the corresponding amines in the presence of N,N′-carbonyldiimidazole in the dioxane medium, a systematic series of 2-(2,4-dioxo-1,4-dihydroquinazolin-3(2H)-yl)-N-R-acetamides was obtained. A novel approach to synthesis of the key intermediate - 2-(2,4-dioxo-1,4-dihydro-quinazolin-3(2H)-yl)acetic acid was developed. The structure and purity of the resulting substances was confirmed by elemental analysis, 1H NMR, 13C NMR spectroscopy and LC/MS. Based on the results of docking studies using SCIGRESS software, selected compounds with the best affinity for anticonvulsant protein biomes (PDB codes: 4COF, 3F8E and 1 EOU) are promising for experimental studies of anticonvulsant activity. A comparative analysis of the results of molecular docking and in vivo results suggests that there is a positive correlation between scoring protein inhibition and experimental data. Pharmacological studies have revealed the leader compound 2-(2,4-dioxo-1,4-dihydroquinazolin-3(2H)-yl)-N-[(2,4-dichlorophenyl)methyl]acet-amide, which improved all the experimental convulsive syndrome rates in mice without motor coordination impairment and may be recommended for further research. The lowest values of the scoring function of the ligand-peptide interaction are obtained for the synthesized compound and сarbonic anhydrase II (gene name CA2) (PDB code 1 EOU), so its inhibition is proposed by us as the most probable mechanism of the anticonvulsive effect of the leader compound.

© 2018, Media Sphera Publishing Group. All rights reserved. Despite decades of research, neurobiological studies of depression haven’t achieved significant results. Many experts propose that one of the main reasons for this failure is current diagnostic standards not considering the heterogeneity and polymorphism of depression. Research is unable to identify specific neurobiological changes due to formal diagnosis «major depressive disorder» and new diagnostic criteria are needed. RDoC (Research Domain Criteria) has intensified the confrontation between biological and clinical researchers and changes in approach to depressive psychopathology are discussed. A review presents the recent approaches used in studies of depressive disorders, the methodology they use, the scientific paradigms they rely on.

© 2018 Elsevier Ltd Biological effects of hormones in both plants and animals are based on high-affinity interaction with cognate receptors resulting in their activation. The signal of cytokinins, classical plant hormones, is perceived in Arabidopsis by three homologous membrane receptors: AHK2, AHK3, and CRE1/AHK4. To study the cytokinin–receptor interaction, we used 25 derivatives of potent cytokinin N6-benzyladenine (BA) with substituents in the purine heterocycle and/or in the side chain. The study was focused primarily on individual cytokinin receptors from Arabidopsis. The main in planta assay system was based on Arabidopsis double mutants retaining only one isoform of cytokinin receptors and harboring cytokinin-sensitive reporter gene. Classical cytokinin biotest with Amaranthus seedlings was used as an additional biotest. In parallel, the binding of ligands to individual cytokinin receptors was assessed in the in vitro test system. Quantitative comparison of results of different assays confirmed the partial similarity of ligand-binding properties of receptor isoforms. Substituents at positions 8 and 9 of adenine moiety, elongated linker up to 4 methylene units, and replacement of N6 by sulfur or oxygen have resulted in the suppression of cytokinin activity of the derivative toward all receptors. Introduction of a halogen into position 2 of adenine moiety, on the contrary, often increased the ligand activity, especially toward AHK3. Features both common and distinctive of cytokinin receptors in Arabidopsis and Amaranthus were revealed, highlighting species specificity of the cytokinin perception apparatus. Correlations between the extent to which a compound binds to a receptor in vitro and its ability to activate the same receptor in planta were evaluated for each AHK protein. Interaction patterns between individual receptors and ligands were rationalized by structure analysis and molecular docking in sensory modules of AHK receptors. The best correlation between docking scores and specific binding was observed for AHK3. In addition, receptor-specific ligands have been discovered with unique properties to predominantly activate or block distinct cytokinin receptors. These ligands are promising for practical application and as molecular tools in the study of the cytokinin perception by plant cells.

© 2017 Elsevier B.V. Two series of palladium(II) and platinum(II) complexes featuring esters of tetrazol-1-yl and tetrazol-5-ylacetic acids {trans-[PdCl2L2] and trans-[PtCl2L2], L = 5-methyl-1H-tetrazol-1-ylacetic acid and its ethyl, butyl, isobutyl esters (1–5); 2-R-2H-tetrazol-5-ylacetic acid and its ethyl esters, R = tBu, CH2CH2OH (6–10)} were synthesized and their binding to calf-thymus DNA (CT DNA) and bovine serum albumin (BSA) were studied by means of experimental (CD, UV, viscometry, fluorometric and electrophoretic techniques) and theoretical methods. According to the spectrophotometric data, the interaction of the metal complexes with CT DNA is observed. The significant increase of melting point of CT DNA in the presence of the metal complexes (ΔTm = 8–13 °C) indicates strong stabilization of the DNA helix. Electrophoretic studies demonstrate the ability of the metal complexes to interact with pBR322 plasmid DNA and to change its mobility. According to the data of the fluorescence quenching technique, binding with constants (Kbin) of Pd(II) complexes with BSA are in the range 0.83–4.12 × 105 L M−1. The molecular docking studies show the minor groove binding behavior of tetrazole-containing palladium(II) and platinum(II) complexes to DNA (ΔGbinding. −5.56 − −6.12 kcal/mol) and effective binding to BSA via the favored binding site Trp213 (ΔGbinding −7.2 − −7.56 kcal/mol). The complex trans-[PtCl2(2-tert-butyl-tetrazol-5-ylacetic acid)2] exhibited noticeable antiproliferative activity in two human cancer cell lines with IC50 values of 11.40 µM in HT-29 cells and 11.02 µM in MDA-MB-231 cell line.

© The Author 2018. An in silico approach was adopted to identify potential cyclooxygenase inhibitors through molecular docking studies. Four potentially active molecules were generated by fusion of dopamine with ibuprofen or ketorolac derivatives. The binding mode of the considered ligands to cyclooxygenase-1 and cyclooxygenase-2 isoforms was described using Autodock Vina. Preliminary docking to full cyclooxygenase isoforms structures was used to determine possible binding sites for the described dopamine-derived ligands. The following more accurate docking iteration to the described binding sites was used to achieve better conformational sampling. Among the studied molecules, IBU-GABA-DA showed preferable binding to cyclooxygenase active site of cyclooxygenase-1, while IBU-DA bound to peroxidase site of cyclooxygenase-1, making these ibuprofen-comprising ligands a base for further research and design of selective cyclooxygenase- 1 inhibitors. Keterolac-derived ligands KET-DA and KET-GABA-DA demonstrated binding to both cyclooxygenase isoforms at a side pocket, which does not relate to any known functional site of cyclooxygenases and needs to be further investigated.

© ISUCT Publishing. The macrolide antibiotic oligomycin A (1), produced by actinomycetes Streptomyces,[1] is a well-known inhibitor of FO F1 ATP-synthase, which is regarded as a molecular target for new drugs in the treatment of tumors and infections. Oligomycin A (1) exhibits antifungal and cytotoxic activities, but Gram-negative and Gram-positive bacteria are resistant to 1 except actinobacteria.[2] In micromolar concentrations, oligomycin binds to FO c-subunit, blocks proton translocation and disrupts bioenergetic metabolism.[3] However, a clinical application of oligomycin A is limited by high cytotoxicity for mammalian cells. The searches of new derivatives of oligomycin A with more selective pharmacological activity and low toxicity for normal cells are of great interest. New semi-synthetic oligomycins also would be valuable for SAR studies and depicting the mechanism of FO F1 ATP-synthase inhibition. The complicity of oligomycin structure and its lability in basic conditions[4] significantly impede modifications and an applicability of this antibiotic. However, previously we have managed this challenge and developed some modifications of the side chain and chemical transformations of the lactone moiety of 1.[4-9] In this paper, throughout our research we describe synthesis and biological investigation of novel oligomycin A derivatives, namely 16,33-O,O-diformyl-16,17-dihydro-16(S),17(R)-dihydroxyoligomycin A (3) and 33-O-formyloligomycin A (4). First, we have studied Prilezhaev epoxidation of double bonds in core structure of oligomycin A. It was found that treatment 1 with m-CPBA at -17oC in dichloromethane led to 16,17-epoxyoligomycin (2). Unfortunately, all attempts for isolation of product 2 were failed due to its instability on silica gel, and, consequently, we were unable to determine the structure of 2 by direct physicochemical and spectral methods. The presence of epoxide at C16-C19 positions was confirmed by tandem mass spectrometry, but its exact localization was still elusive. We assumed that it might be at C16-C17 positions, because C18-C19 double bond is hindered by ethyl side chain at C20. In order to obtain a stable oligomycin A derivative we performed an epoxide ring-opening reaction by the treatment of the crude epoxyoligomycin 2 with formic acid. This acid-catalyzed opening of the epoxide accompanied with acylation of 33-OH group and led to16,33-O,O-diformyl-16,17-dihydro-16(S),17(R)-dihydroxyoligomycin A (3). The structure of 3 was confirmed by NMR spectroscopy and high resolution mass spectrometry. Configurations at C16 and C17 positions were determined by detecting correlations in1H-1H ROESY spectrum. Obtained results allowed to confirm an assumption about localization of the epoxide ring and establish the structure of 2 as (R,R)-16,17-epoxyoligomycin A, since inversion of configuration has taken place at the attacked carbon atom.[23] It is known that O-acyl derivatives of pharmacologically active agents are widely used as prodrugs.[24] Acylation of 2-hydroxypropyl side chain in 2 prompts us to examine the reaction of oligomycin A (1) with formic acid. Thus, stirring the solution of 1 in HCOOH (98 %) for 2 h at room temperature afforded 33-O-formyloligomycin A (4) in a good yield. The structure of 4 was confirmed by NMR-spectroscopy and high resolution mass spectrometry. Also, biological data of new derivatives were evaluated. The modification of C16-C17 positions of the macrocycle as well as acylation of C33 hydroxyl group led to the decreasing of activity against S. fradiae, Candida spp. and filamentous fungi. Obtained results were in agreement with docking studies. A simulation of an interaction of 1, 3 and 4 with the FO subunit of the ATP-synthase (PDB: 4f4s) revealed that these modifications led to a significant change in the solvation energy and an increase in the conformational capacity of the ligands during the binding with the target. This resulted in decrease of the binding affinity for derivatives 2, 3. However, 33-O-formyloligomycin A (4) showed similar antiproliferative activity against tumor cell lines (HCT-116 colon carcinoma, К562 myeloid leukemia cell lines and MDR K562/4 subline) as for 1, but less cytotoxic for non-malignant human cells.