title: Interaction of a copper (II) complex containing an artificial sweetener (aspartame) with calf thymus DNA.
abstract: A copper (II) complex containing aspartame (APM) as ligand, Cu(APM)2Cl2⋅2H2O, was synthesized and characterized. In vitro binding interaction of this complex with native calf thymus DNA (CT-DNA) was studied at physiological pH. The interaction was studied using different methods: spectrophotometric, spectrofluorometric, competition experiment, circular dichroism (CD) and viscosimetric techniques. Hyperchromicity was observed in UV absorption band of Cu(APM)2Cl2⋅2H2O. A strong fluorescence quenching reaction of DNA to Cu(APM)2Cl2⋅2H2O was observed and the binding constants (Kf) and corresponding numbers of binding sites (n) were calculated at different temperatures. Thermodynamic parameters, enthalpy change (ΔH) and entropy change (ΔS) were calculated to be+89.3 kJ mol(-1) and+379.3 J mol(-1) K(-1) according to Van't Hoff equation which indicated that reaction is predominantly entropically driven. Experimental results from spectroscopic methods were comparable and further supported by viscosity measurements. We suggest that Cu(APM)2Cl2⋅2H2O interacts with calf thymus DNA via a groove interaction mode with an intrinsic binding constant of 8×10+4 M(-1). Binding of this copper complex to DNA was found to be stronger compared to aspartame which was studied recently.
authors.affiliation: Department of Inorganic Chemistry, Faculty of Chemistry, Razi University, Kermanshah, Islamic Republic of Iran. Electronic address: nahidshahabadi@yahoo.com.
authors.forename: Nahid
authors.initials: N
authors.lastname: Shahabadi
authors.affiliation: Department of Chemistry, Sensor and Biosensor Research Center (SBRC) & Nanoscience and Nanotechnology Research Center (NNRC), Faculty of Chemistry, Razi University, Kermanshah, Islamic Republic of Iran. Electronic address: mm_khodaei@yahoo.com.
authors.forename: Mohammad Mehdi
authors.initials: MM
authors.lastname: Khodaei
authors.affiliation: Department of Chemistry, Sensor and Biosensor Research Center (SBRC) & Nanoscience and Nanotechnology Research Center (NNRC), Faculty of Chemistry, Razi University, Kermanshah, Islamic Republic of Iran.
authors.forename: Soheila
authors.initials: S
authors.lastname: Kashanian
authors.affiliation: Department of Applied Chemistry, Faculty of Chemistry, Razi University, Kermanshah, Islamic Republic of Iran.
authors.forename: Fahimeh
authors.initials: F
authors.lastname: Kheirdoosh
mesh_terms: D000818:Animals; D001218:Aspartame / Q000031:analogs & derivatives / Q000378:metabolism*; D001665:Binding Sites; D002417:Cattle; D002942:Circular Dichroism; D056831:Coordination Complexes / Q000031:analogs & derivatives / Q000378:metabolism*; D003300:Copper / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D013050:Spectrometry, Fluorescence; D013549:Sweetening Agents / Q000737:chemistry / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D056831:Coordination Complexes; D013549:Sweetening Agents; D003300:Copper; D004247:DNA; C427203:calf thymus DNA; D001218:Aspartame
keywords: Aspartame; Calf thymus DNA (CT-DNA); Cu(APM)(2)Cl(2)⋅2H(2)O; Groove binding; Spectroscopy