Yelekçi, Kemal
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Kemal Y.
KEMAL YELEKÇI
Yelekci K.
Y., Kemal
Yelekçi, Kemal
Yelekci, Kemal
Yelekçi K.
Y.,Kemal
Yelekçi, KEMAL
Yelekçi,K.
Kemal YELEKÇI
YELEKÇI, Kemal
Yelekci,Kemal
Kemal, Yelekci
K. Yelekçi
YELEKÇI, KEMAL
Yelekçi, K.
Kemal Yelekçi
Yelekci,K.
Kemal, Yelekçi
Yelekçi, Kemal
Yelekçi, Kemal
KEMAL YELEKÇI
Yelekci K.
Y., Kemal
Yelekçi, Kemal
Yelekci, Kemal
Yelekçi K.
Y.,Kemal
Yelekçi, KEMAL
Yelekçi,K.
Kemal YELEKÇI
YELEKÇI, Kemal
Yelekci,Kemal
Kemal, Yelekci
K. Yelekçi
YELEKÇI, KEMAL
Yelekçi, K.
Kemal Yelekçi
Yelekci,K.
Kemal, Yelekçi
Yelekçi, Kemal
Yelekçi, Kemal
Job Title
Prof. Dr.
Email Address
yelekci@khas.edu.tr
Main Affiliation
Molecular Biology and Genetics
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Scholarly Output
100
Articles
59
Citation Count
1305
Supervised Theses
26
21 results
Scholarly Output Search Results
Now showing 1 - 10 of 21
Article Citation - WoS: 11Citation - Scopus: 10Homology Modeling Andin Silicodesign of Novel and Potential Dual-Acting Inhibitors of Human Histone Deacetylases Hdac5 and Hdac9 Isozymes(2020) Elmezayen, Ammar D.; Yelekçi, Kemal; Yelekçi, Kemal; Molecular Biology and GeneticsHistone deacetylases (HDACs) are a group of enzymes that have prominent and crucial effect on various biological systems, mainly by their suppressive effect on transcription. Searching for inhibitors targeting their respective isoforms without affecting other targets is greatly needed. Some histone deacetylases have no crystal structures, such as HDAC5 and HDAC9. Lacking proper and suitable crystal structure is obstructing the designing of appropriate isoform selective inhibitors. Here in this study, we constructed human HDAC5 and HDAC9 protein models using human HDAC4 (PDB:2VQM_A) as a template by the means of homology modeling approach. Based on the Z-score of the built models, model M0014 of HDAC5 and model M0020 of HDAC9 were selected. The models were verified by MODELLER and validated using the Web-based PROCHECK server. All selected known inhibitors displayed reasonable binding modes and equivalent predicted Ki values in comparison to the experimental binding affinities (Ki/IC50). The known inhibitor Rac26 showed the best binding affinity for HDAC5, while TMP269 showed the best binding affinity for HDAC9. The best two compounds, CHEMBL2114980 and CHEMBL217223, had relatively similar inhibition constants against HDAC5 and HDAC9. The built models and their complexes were subjected to molecular dynamic simulations (MD) for 100 ns. Examining the MD simulation results of all studied structures, including the RMSD, RMSF, radius of gyration and potential energy suggested the stability and reliability of the built models. Accordingly, the results obtained in this study could be used for designing de novo inhibitors against HDAC5 and HDAC9. Communicated by Ramaswamy H. SarmaArticle Citation - WoS: 11Citation - Scopus: 20Evaluation of Selective Human Mao Inhibitory Activities of Some Novel Pyrazoline Derivatives(SPRINGER WIEN, 2013) Salgin-Goksen, Umut; Yelekçi, Kemal; Yabanoglu-Ciftci, Samiye; Ercan, Ayse; Yelekçi, Kemal; Ucar, Gulberk; Gokhan-Kelekçi, Nesrin; Molecular Biology and GeneticsA series of 1-[2-((5-methyl/chloro)-2-benzoxazolinone-3-yl)acetyl]-35-diaryl-45-dihydro-1H-pyrazole derivatives were prepared by reacting 2-((5-methyl/chloro)-2-benzoxazolinone-3-yl)acetylhydrazine with appropriate chalcones. The chemical structures of all compounds were confirmed by elemental analyses IR H-1 NMR and ESI-MS. All the compounds were investigated for their ability to selectively inhibit monoamine oxidase (MAO) by in vitro tests. MAO activities of the compounds were compared with moclobemide and selegiline and all the compounds were found to inhibit human MAO-A selectively. The inhibition profile was found to be competitive and reversible for all compounds by in vitro tests. Among the compounds examined compounds 5ae 5af and 5ag were more selective than moclobemide with respect to the K (i) values experimentally found. In addition the compound 5bg showed MAO-A inhibitor activity as well as moclobemide. A series of experimentally tested compounds (5ae-5ch) were docked computationally to the active site of the MAO-A and MAO-B isoenzyme. The AUTODOCK 4.01 program was employed to perform automated molecular docking.Article Citation - WoS: 27Citation - Scopus: 31Homology Modeling of Human Histone Deacetylase 10 and Design of Potential Selective Inhibitors(Taylor & Francis Inc, 2019) Uba, Abdullahi Ibrahim; Yelekçi, Kemal; Yelekçi, Kemal; Molecular Biology and GeneticsHistone deacetylases (HDACs) are implicated in the pathology of various cancers, and their pharmacological blockade has proven to be promising in reversing the malignant phenotypes. However, lack of crystal structures of some of the human HDAC isoforms (e.g., HDAC10) hinders the design of the isoform-selective inhibitor. Here, the recently solved X-ray crystal structure of Danio rerio (zebrafish) HDAC10 (Protein Data Bank (PDB) ID; 5TD7, released on 24 May 2017) was retrieved from the PDB and used as a template structure to model the three-dimensional structure of human HDAC10. The overall quality of the best model (M0017) was assessed by computing its z-score-a measure of the deviation of the total energy of the structure with respect to an energy distribution derived from random conformations and by docking of known HDAC10 inhibitors to its catalytic cavity. Furthermore, to identify potential HDAC10-selective inhibitor ligand-based virtual screening was carried out against the ZINC database. The free modeled structure of HDAC10 and its complexes with quisinostat and the highest-ranked compound ZINC19749069 were submitted to molecular dynamics simulation. The comparative analysis of root-mean-squared deviation, root-mean-squared fluctuation, radius of gyration (Rg), and potential energy of these systems showed that HDAC10-ZINC19749069 complex remained the most stable over time. Thus, M0017 could be potentially used for structure-based inhibitor against HDAC10, and ZINC19749069 may provide a scaffold for further optimization. Communicated by Ramaswamy H. SarmaArticle Citation - WoS: 153Citation - Scopus: 171Molecular Modifications on Carboxylic Acid Derivatives as Potent Histone Deacetylase Inhibitors: Activity and Docking Studies(Pergamon-Elsevier Science Ltd, 2009) Bora-Tatar, Gamze; Yelekçi, Kemal; Dayangac-Erden, Didem; Demir, Ayhan S.; Dalkara, Sevim; Yelekçi, Kemal; Erdem-Yurter, Hayat; Molecular Biology and GeneticsIn the light of known HDAC inhibitors 33 carboxylic acid derivatives were tested to understand the structural requirements for HDAC inhibition activity. Several modifications were applied to develop the structure-activity relationships of carboxylic acid HDAC inhibitors. HDAC inhibition activities were investigated in vitro by using HeLa nuclear extract in a fluorimetric assay. Molecular docking was also carried out for the human HDAC8 enzyme in order to predict inhibition activity and the 3D poses of inhibitor-enzyme complexes. Of these compounds caffeic acid derivatives such as chlorogenic acid and curcumin were found to be highly potent compared to sodium butyrate which is a well-known HDAC inhibitor. (C) 2009 Elsevier Ltd. All rights reserved.Article Citation - WoS: 16Citation - Scopus: 18Synthesis Molecular Modeling and in Vitro Screening of Monoamine Oxidase Inhibitory Activities of Some Novel Hydrazone Derivatives(SPRINGER WIEN, 2013) Salgin-Goksen, Umut; Yelekçi, Kemal; Gokhan-Kelekçi, Nesrin; Yabanoglu-Ciftci, Samiye; Yelekçi, Kemal; Ucar, Gulberk; Molecular Biology and GeneticsThirteen 2-[2-(5-methyl-2-benzoxazolinone-3-yl)acetyl]-3/4/5-substituted benzylidenehydrazine derivatives were synthesized by reacting 2-(5-methyl-2-benzoxazolinone-3-yl)acetylhydrazine and substituted benzaldehydes in neutral and acid/base catalyzed conditions and a comparison was made in terms of their yields and reaction times. The structures of all compounds were confirmed by IR H-1 NMR C-13 NMR mass spectral data and elemental analyses. All the compounds were investigated for their ability to selectively inhibit MAO isoforms by in vitro tests and were found to inhibit recombinant human MAO-B selectively and reversibly in a competitive manner. Among the compounds examined compound 16 was found to be more selective than selegiline a known MAO-B inhibitor in respect to the K (i) values experimentally found. Additionally compounds 9 and 15 showed moderate MAO-B inhibitor activity. The interaction of compounds with MAO isoforms was investigated by molecular docking studies using recently published crystallographic models of MAO-A and MAO-B. The results obtained from the docking studies were found to be in good agreement with the experimental values.Article Citation - WoS: 21Citation - Scopus: 27Synthesis and Screening of Human Monoamine Oxidase-A Inhibitor Effect of New 2-Pyrazoline and Hydrazone Derivatives(Wiley-VCH Verlag GmbH, 2015) Evranos-Aksoz, Begüm; Yelekçi, Kemal; Baysal, İpek; Yabanoğlu-Çiftçi, Samiye; Djikic, Teodora; Yelekçi, Kemal; Uçar, Gülberk; Ertan, Rahmiye; Molecular Biology and GeneticsA group of 35-diaryl-2-pyrazoline and hydrazone derivatives was prepared via the reaction of various chalcones with hydrazide compounds in ethanol. Twenty original compounds were synthesized. Ten of these original compounds have a pyrazoline structure nine of these original compounds have a hydrazone structure and one of these original compounds has a chalcone structure. Structural elucidation of the compounds was performed by IR H-1 NMR C-13 NMR mass spectral data and elemental analyses. These compounds were tested for their inhibitory activities toward the A and B isoforms of human monoamine oxidase (MAO). Except for 3k and 6c all compounds were found to be competitive reversible and selective inhibitors for either one of the isoforms (hMAO-A or MAO-B). Compounds 3k and 6c were found to be competitive reversible but non-selective MAO inhibitors. Compound 6h showed hMAO-B inhibitory activity whereas the others potently inhibited hMAO-A. Compound 5c showed higher selectivity than the standard drug moclobemide. According to the experimental K-i values compounds 6i 6d and 6a exhibited the highest inhibitory activity toward hMAO-A. The AutoDock 4.2 program was employed to perform automated molecular docking. The calculated results obtained computationally were in good agreement with the experimental values.Article Citation - WoS: 46Citation - Scopus: 46Histone Deacetylase Inhibition Activity and Molecular Docking of (e )-Resveratrol: Its Therapeutic Potential in Spinal Muscular Atrophy(Wiley, 2009) Dayangac-Erden, Didem; Yelekçi, Kemal; Bora, Gamze; Ayhan, Peruze; Kocaefe, Çetin; Dalkara, Sevim; Yelekçi, Kemal; Demir, Ayhan S.; Erdem-Yurter, Hayat; Molecular Biology and GeneticsSpinal muscular atrophy is an autosomal recessive motor neuron disease that is caused by mutation of the survival motor neuron gene (SMN1) but all patients retain a nearly identical copy SMN2. The disease severity correlates inversely with increased SMN2 copy. Currently the most promising therapeutic strategy for spinal muscular atrophy is induction of SMN2 gene expression by histone deacetylase inhibitors. Polyphenols are known for protection against oxidative stress and degenerative diseases. Among our candidate prodrug library we found that (E )-resveratrol which is one of the polyphenolic compounds inhibited histone deacetylase activity in a concentration-dependent manner and half-maximum inhibition was observed at 650 mu m. Molecular docking studies showed that (E )-resveratrol had more favorable free energy of binding (-9.09 kcal/mol) and inhibition constant values (0.219 mu m) than known inhibitors. To evaluate the effect of (E )-resveratrol on SMN2 expression spinal muscular atrophy type I fibroblast cell lines was treated with (E )-resveratrol. The level of full-length SMN2 mRNA and protein showed 1.2- to 1.3-fold increase after treatment with 100 mu m (E )-resveratrol in only one cell line. These results indicate that response to (E )-resveratrol treatment is variable among cell lines. This data demonstrate a novel activity of (E )-resveratrol and that it could be a promising candidate for the treatment of spinal muscular atrophy.Article Citation - WoS: 6Citation - Scopus: 6Synthesis Molecular Modelling and Antibacterial Activity Against Helicobacter Pylori of Novel Diflunisal Derivatives as Urease Enzyme Inhibitors(Bentham Science Publ Ltd, 2019) Coşkun, Göknil Pelin; Yelekçi, Kemal; Djikic, Teodora; Kalaycı, Sadık; Yelekçi, Kemal; Şahin, Fikrettin; Küçükgüzel, Şükriye Güniz; Molecular Biology and GeneticsBackground: The main factor for the prolongation of the ulcer treatment in the gastrointestinal system would be Helicobacter pylori infection which can possibly lead to gastrointestinal cancer. Triple therapy is the treatment of choice by today's standards. However observed resistance among the bacterial strains can make the situation even worse. Therefore there is a need to discover new targeted antibacterial therapy in order to make success in the eradication of H. pylori infections. Methods: The targeted therapy rule is to identify the related macromolecules that are responsible for the survival of the bacteria. Thus 2-[(2'4'-difluoro-4-hydroxybiphenyl-3-yl)carbonyl]-N-( substituted)hydrazinocarbothioamide (3-13) and 5-(2'4'-difluoro-4-hydroxybiphenyl-3-yl)-4-( substituted)-24-dihydro-3H-124-triazole-3-thiones (14-17) were synthesized and evaluated for antibacterial activity in vitro against H. pylori. Results: All of the tested compounds showed remarkable antibacterial activity compared to the standard drugs (Ornidazole Metronidazole Nitrimidazin and Clarithromycin). Compounds 4 and 13 showed activity as 2 mu g/ml MIC value. Conclusion: In addition we have investigated binding modes and energy of the compounds 4 and 13 on urease enzyme active by using the molecular docking tools.Article Citation - WoS: 8Citation - Scopus: 10Synthesis, in Silico Studies and Cytotoxicity Evaluation of Novel 1,3,4-Oxadiazole Derivatives Designed as Potential Mpges-1 Inhibitors(MARMARA UNIV, 2020) Erensoy, Gizem; Yelekçi, Kemal; Ding, Kai; Zhan, Chang-Guo; Elmezayen, Ammar D.; Yelekçi, Kemal; Duracık, Merve; Özakpınar, Özlem Bingol; Küçükgüzel, İlkay; Molecular Biology and GeneticsA series of new 1,3,4-oxadizole derivatives containing thioether group, has been synthesized to investigate their mPGES-1 inhibitory activities. The synthesized compounds were also evaluated for their anticancer and COX-1/2 inhibitory activities. All compounds were checked for their purity using TLC and HPLC analyses. The melting points, elemental analysis, FT-IR, H-1-/C-13-NMR and LR-MS data were utilized for structural characterization. The most potent derivative was 2-[5-{[2-methyl-5-(propan-2-yl)phenoxy]methyl}-1,3,4-oxadiazol-2-yl)sulphanyl]-1-(phenyl)ethan-1-one 3a, which showed inhibitory activity against mPGES-1 with an IC50 of 4.95 mu M. Docking studies with mPGES-1 and COX-1/2 enzymes revealed their affinity and potential binding mechanism for the tested compounds.Article Citation - WoS: 18Citation - Scopus: 20Pharmacophore-Based Virtual Screening for Identification of Potential Selective Inhibitors of Human Histone Deacetylase 6(Elsevier Sci Ltd, 2018) Uba, Abdullahi Ibrahim; Yelekçi, Kemal; Yelekçi, Kemal; Molecular Biology and GeneticsHistone deacetylase (HDAC) 6 plays a role in oncogenic transformation and cancer metastasis via tubulin deacetylation, making it a critical target for anticancer drug design. However, lack of selectivity shown by many of the current HDAC6 inhibitors in clinical use and trials prompts the continuous search for selective inhibitors. Here, 10 pharmacophore hypotheses were developed based on the 3D common features of training set of 20 HDAC inhibitors in clinical use and trials. The hypotheses were validated using a test set of another 20 HDAC inhibitors along with 400 inactive (decoys) molecules based on Giiner-Henry pharmacophore scoring method. Hypothesis 1 consisting of 1 H-bond donor, 1 H-bond acceptor and 2 hydrophobic features, was used to screen "DruglikeDiverse" database using Biovia Discovery Studio 4.5. The top 10 hit compounds were selected based on the pharmacophore fit values ( > 3.00). Their binding affinity against HDAC6 compared to class I HDACs (1, 2, 3 & 8) and a class IIa member (HDAC7), was calculated by molecular docking using AutoDock4. The stability of binding modes of 2 potential HDAC6-selective inhibitors (ENA501965 and IBS399024) was examined by 30 ns-molecular dynamics (MD) simulation using nanoscale MD (NAMD) software. Both ligands showed potential stability in HDAC6 active site over time. Therefore, these may provide additional scaffolds for further optimization towards the design of safe, potent and selective HDAC6 inhibitors.
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