title: Experimental and molecular modeling studies of the interaction of the polypyridyl Fe(II) and Fe(III) complexes with DNA and BSA.
abstract: Two mononuclear iron complexes, [Fe(tppz)₂](PF₆)₂·H₂O (1) and Fe(tppz)Cl₃·2CHCl₃ (2) where tppz is (2,3,5,6-tetra(2-pyridyl)pyrazine), have been synthesized and characterized by elemental analysis, spectroscopic methods (UV-Vis and IR) and single crystal X-ray structure analysis. The interaction of (1) as the nitrate salt ([Fe(tppz)₂](NO₃)₂) with calf-thymus DNA (CT-DNA) has been monitored by UV-Vis spectroscopy, competitive fluorescence titration, circular dichroism (CD), voltammetric techniques, viscosity measurement, and gel electrophoresis. Gel electrophoresis of DNA with [Fe(tppz)₂](NO₃)₂ demonstrated that the complex also has the ability to cleave supercoiled plasmid DNA. The results have indicated that the complex binds to CT-DNA by three binding modes, viz., electrostatic, groove and partial insertion of the pyridyl rings between the base stacks of double-stranded DNA. Molecular docking of [Fe(tppz)₂](NO₃)₂ with the DNA sequence d(ACCGACGTCGGT)₂ suggests the complex fits into the major groove. The water-insoluble complex (2) can catalyze the cleavage of BSA at 40 °C. There are no reports of the catalytic effect of polypyridyl metal complexes on the BSA cleavage. Molecular docking of (2) with BSA suggests that, when the chloro ligands in the axial positions are replaced by water molecules, the BSA can interact with the Fe(III) complex more easily.
authors.affiliation: Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran.
authors.forename: Mohammad Taghi
authors.initials: MT
authors.lastname: Behnamfar
authors.affiliation: Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran. Electronic address: hadad@cc.iut.ac.ir.
authors.forename: Hassan
authors.initials: H
authors.lastname: Hadadzadeh
authors.affiliation: Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.
authors.forename: Jim
authors.initials: J
authors.lastname: Simpson
authors.affiliation: Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran.
authors.forename: Farivash
authors.initials: F
authors.lastname: Darabi
authors.affiliation: Department of Agricultural Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran.
authors.forename: Azar
authors.initials: A
authors.lastname: Shahpiri
authors.affiliation: Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran.
authors.forename: Taghi
authors.initials: T
authors.lastname: Khayamian
authors.affiliation: Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran.
authors.forename: Malihe
authors.initials: M
authors.lastname: Ebrahimi
authors.affiliation: Faculty of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran.
authors.forename: Hadi
authors.initials: H
authors.lastname: Amiri Rudbari
authors.affiliation: Physiology and Pharmacology Department, Pasteur Institute of Iran, Tehran, P.O. Box 13164, Iran.
authors.forename: Mona
authors.initials: M
authors.lastname: Salimi
mesh_terms: D000818:Animals; D002417:Cattle; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D053837:DNA Cleavage / Q000187:drug effects; D005290:Ferric Compounds / Q000737:chemistry* / Q000494:pharmacology; D005296:Ferrous Compounds / Q000737:chemistry* / Q000494:pharmacology; D062105:Molecular Docking Simulation; D011719:Pyrazines / Q000737:chemistry* / Q000494:pharmacology; D012710:Serum Albumin, Bovine / Q000378:metabolism*
chemical_list: D005290:Ferric Compounds; D005296:Ferrous Compounds; D011719:Pyrazines; D012710:Serum Albumin, Bovine; D004247:DNA; C427203:calf thymus DNA
keywords: 2,3,5,6-Tetra(2-pyridyl)pyrazine (tppz); BSA; Catalytic effect; DNA; Iron; Molecular modeling