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Öğe BSA/DNA binding behavior and the photophysicochemical properties of novel water soluble zinc(II)phthalocyanines directly substituted with piperazine groups(Springer, 2021) Khezami, Khaoula; Harmandar, Kevser; Bagda, Esra; Bagda, Efkan; Sahin, Gamze; Karakodak, Nursen; Durmus, MahmutIn the current research, two novel zinc(II) phthalocyanines (ZnPcs) (1 and 2) directly connecting with 4-(4-methylpiperazin-1-yl)phenyl groups have been synthesized through the Suzuki-Miyaura coupling reaction. These ZnPcs 1 and 2 were converted to their water-soluble derivatives (1Q and 2Q) by quaternization. The photochemical and photophysical properties were determined in DMSO for the non-ionic zinc(II) phthalocyanines (1 and 2) and in both DMSO and aqueous solutions for the quaternized cationic derivatives (1Q and 2Q) to establish their photosensitizer capabilities in photodynamic therapy (PDT). The spectrofluorometric and spectrophotometric techniques were employed for the determination of interaction between water-soluble ZnPcs (1Q and 2Q) and BSA or ct-DNA. The binding constants of these compounds to BSA were found in the order of 10(8) M-1. The binding constant of the ct-DNA interaction with 2Q (1.09 x 10(5) M-1) was found higher than 1Q (6.87 x 10(4) M-1). The thermodynamic constants were determined for both 1Q and 2Q. The endothermic and spontaneous nature of interaction was observed with ct-DNA. Besides, the thermal denaturation and viscosity studies proved the non-intercalative mode of binding for both compounds to ct-DNA. [GRAPHICS] .Öğe G-quadruplex and calf thymus DNA interaction of quaternized tetra and octa pyridyloxy substituted indium (III) phthalocyanines(ELSEVIER SCIENCE SA, 2017) Bagda, Efkan; Bagda, Esra; Durmus, MahmutThe interactions of small molecules with G-quadruplex and double stranded DNA are important due to their potential biological and medical usages. In the present paper, the interactions of indium (III) phthalocyanines (quaternized 2,3,9,10,16,17,23,24-octakis-[(3-pyridyloxy) phthalocyaninato] chloroindium(III): OInPc and quaternized 2(3),9(10),16(17),23(24)-tetrakis-[(3-pyridyloxy) phthalocyaninato] chloroindium(III): TInPc) with hybrid G-quadruplex (Tel 21) and parallel G-quadruplexes (nucleolin, KRAS, c-MYC, vegf) were studied. The interactions of these phthalocyanines with ctDNA were also investigated. These interactions were measured by different spectroscopic techniques such as UV-Vis, fluorescence and circular dichroism. The UV-Vis spectroscopic data treated with Benesi-Hildebrand equation and Benesi-Hildebrand constants (K-BH) were calculated. These constants were found higher for octa peripheral pyridyloxy substituted phthalocyanine, OInPc. Besides, UV-Vis analysis showed that the interaction of G-quadruplexes with tetra peripheral pyridyloxy substituted phthalocyanine derivative (TInPc) resulted in removal of central indium (III) atom from the cavity of phthalocyanine macrocycle. The UV-Vis melting studies as well as fluorescence replacement techniques were also employed for clarification of mechanism. The binding mode of molecules with ct DNA was also supported with viscosity measurements. From the results, the stabilization and destabilization of G-quadruplex depending on the concentration of the OInPc and TInPc showed that these two indium (III) phthalocyanines have the potential of both the elucidation role of G-quadruplexes in gene expression and the usage in cancer therapy.Öğe Interaction of water soluble phthalocyanine compounds with parallel and hybrid G-quadruplex DNA molecules(Pergamon-Elsevier Science Ltd, 2023) Aydin, Fadime; Bagda, Esra; Bagda, Efkan; Durmus, MahmutG-quadruplex DNAs are secondary DNA structures formed in guanine-rich genome sequences, such as telomeres. Due to the increased metabolic activities of cancer cells, the formation probability of G-quadruplex structures increases. Since the formation of G-quadruplex structures and their stabilization with various ligands prevents DNA's turning into straight strands, which are necessary for some processes such as transcription and translation, it may cause disruptions in cell proliferation. Therefore, these DNA constructs are important for anticancer drug targets. In the present study, the interactions of water-soluble MnPc and ZnPc compounds with G-quadruplex DNAs with parallel and hybrid conformation were investigated. KD constants were calculated with spectroscopic titration data. Stoichiometric ratios of DNA-phthalocyanine interactions were determined by Job's method and found between 1:1 to 1:2 for MnPc and 1:1 for ZnPc. The effect of phthalocyanine on the G-quadruplex conformation was investigated by circular dichroism (CD) spectroscopy. Capillary gel electrophoresis studies supported the existence of interactions. DNA polymerase stop assay further supported stabilizing AS1411 and Tel21 G-quadruplex structures with Pc compounds. This work is on a molecular level study. The in vitro and in vivo images can be different because MPcs are localized in the cytoplasmic organelles but rare in the nucleus.Öğe Thermodynamic and structural investigation of the interaction of quaternized 2,3-octakis-[(2-mercaptopyridine)phthalocyaninato] copper (II) sulfate (CuPc) with parallel and hybrid type G-quadruplex(Wiley, 2024) Sahin, Gamze; Bagda, Esra; Temiz, Ozge Goktug; Bagda, Efkan; Ayhan, Ebubekir; Durmus, MahmutG-quadruplexes are important drug targets and get attention due to their existence in telomere, ribosomal DNA, promoter regions of some oncogenes, and the untranslated regions of mRNA. Due to the biological roles of G-quadruplexes, investigating of the G-quadruplex-small molecule interaction is essential. The primary motivation for these studies is the possibility of inhibiting cell functions associated with G-quadruplex sequences by binding with small molecules. Targeting the small molecules to desired tissue with the G-quadruplex vehicles is the second important goal of the G-quadruplex-small molecule interaction studies. In the present study, the new peripherally 2-mercaptopyridine octasubstituted copper(II) phthalocyanine and its quaternized derivative (CuPc) were synthesized and characterized by elemental analysis FT-IR, UV-Vis, and mass spectra. The excellent solubility of CuPc in water is essential for its transport in the organism. Because of this feature, its affinity toward G-quadruplex forming aptamers, AS1411, Tel21, and Tel45, was investigated. The UV-Vis spectrophotometric titration data confirmed the prevention of aggregation upon interaction with G-quadruplex, which is very important for biomedical applications. The CD spectroscopic analyses and binding stoichiometry confirmed the end stacking model for interaction of AS1411 with CuPc. The interaction of CuPc caused the equilibrium shift from hybrid conformation to antiparallel conformation for Tel21 and Tel45. The isothermal titration calorimeter (ITC) was used for the determination of thermodynamic parameters. The thermodynamic data of the interaction was fitted well with the one-site model. The negative values of Gibbs free energy change confirmed the spontaneous nature of the reactions. Besides, the negative values of enthalpy change and entropy change proved that the nature of processes was enthalpy driven. The interaction stoichiometry was 2 for AS1411 and Tel21 and 1.5 for Tel45. The binding constants were 1.3(+/- 0.3) x 10(5), 3.2(+/- 0.4) x 10(5), and 1.1(+/- 0.3) x 10(5) M-1, which were at the level of ethidium bromide intercalation binding constant given in the literature. The DNA polymerase stop assay further supported the interaction of CuPc with G-quadruplex DNA. The experimental results confirm that the CuPc has a potential photosensitizer behaviour for photodynamic therapy.
