Receptor sites in DNA for the dark and photochemical interactions with 4,5'-dimethylangelicin, a potential agent for the photochemotherapy.
The study of the interactions in the ground state between 4,5'-dimethylangelicin, an angular furocoumarin, and various synthetic and natural DNA samples have evidenced the presence in the macromolecule of preferred sequences suitable for binding the small ligand. They are represented by an alternate sequence of purine and pyrimidine bases in each strand of the macromolecule, without difference between the two base pairs A-T and C-G. The study of the photochemical interactions between the same DNA samples and the 4,5'-dimethylangelicin shows that preferred sites are present in the macromolecule for the covalent addition of the furocoumarin to the macromolecule too. These sites however have more strict requirements than those useful for dark binding; they are in fact represented by alternate sequences of A-T in each strand such as those present in poly [d(A-T)] . poly-[d(A-T)]. Moreover fluorescence studies made on the same DNA samples irradiated in the presence of the furocoumarin suggest that the alternate C-G regions favour formation of 4'-5'-fluorescent adducts.
D001482:Base Composition; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000378:metabolism*; D003624:Darkness; D011564:Furocoumarins / Q000378:metabolism* / Q000627:therapeutic use; D006801:Humans; D066298:In Vitro Techniques; D010777:Photochemistry; D010778:Photochemotherapy; D011089:Polydeoxyribonucleotides / Q000378:metabolism; D011565:Psoriasis / Q000188:drug therapy
D011564:Furocoumarins; D011089:Polydeoxyribonucleotides; C021665:4,5'-dimethylangelicin; D004247:DNA