title: Design and non-covalent DNA binding of platinum(II) metallacalix[4]arenes.
abstract: A set of cyclic tetranuclear complexes of the metallacalix[4]arene type with formula [{Pt(en)(L)}(4)](4+) (en=ethylenediamine; 2: LH=5-chloro-2-hydroxypyrimidine (5-Cl-Hpymo); 3: LH=5-bromo-2-hydroxypyrimidine (5-Br-Hpymo); 4: LH=5-iodo-2-hydroxypyrimidine (5-I-Hpymo)) have been obtained from the reaction between cis-protected square-planar [Pt(en)(H(2)O)(2)](2+) metal entities and LH in aqueous media. Additionally, the binding properties of 2, 3, 4 and their congener [{Pt(en)(L)}(4)](4+) (1: LH=2-hydroxypyrimidine (Hpymo)) with calf thymus-DNA (ct-DNA) have been studied by using different techniques including circular and linear dichroism (CD and LD, respectively) and UV-visible absorbance spectroscopies, gel electrophoresis, fluorescence competitive-binding studies and atomic force microscopy (AFM). The results are consistent with significant non-covalent interactions taking place between the polynuclear cyclic species and ct-DNA. Moreover, gel electrophoresis, linear dichroism titrations and AFM images of ct-DNA with metallacalixarenes show ct-DNA coiling at low metallacalixarene concentrations and upon subsequent increments in metallacalixarene concentration ct-DNA can be seen to uncoil with concomitant formation of long and inflexible ct-DNA structures.
authors.affiliation: Departamento de Química Inorgánica Universidad de Granada, Av. Fuentenueva s/n, 18071 Granada, Spain.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Galindo
authors.forename: David
authors.initials: D
authors.lastname: Olea
authors.forename: M Angustias
authors.initials: MA
authors.lastname: Romero
authors.forename: Julio
authors.initials: J
authors.lastname: Gómez
authors.forename: Pedro
authors.initials: P
authors.lastname: del Castillo
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hannon
authors.forename: Alison
authors.initials: A
authors.lastname: Rodger
authors.forename: Félix
authors.initials: F
authors.lastname: Zamora
authors.forename: Jorge A R
authors.initials: JA
authors.lastname: Navarro
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000378:metabolism; D001667:Binding, Competitive; D047250:Calixarenes / Q000737:chemistry*; D002413:Cations, Divalent; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004586:Electrophoresis; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D015394:Molecular Structure; D009944:Organoplatinum Compounds / Q000138:chemical synthesis* / Q000378:metabolism; D010636:Phenols / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D000970:Antineoplastic Agents; D002413:Cations, Divalent; D009944:Organoplatinum Compounds; D010636:Phenols; C121325:calix(4)arene; D014867:Water; D047250:Calixarenes; D010984:Platinum; D004247:DNA; C427203:calf thymus DNA