Berenil complexation with a nucleic acid triple helix.
The interaction of berenil molecule, a minor groove binding drug, with T-A-T triple helix and A-T double helix was studied using circular dichroism spectroscopy and thermal denaturation. The triple helix was made by an oligonucleotide (dA)12-X-(dT)12-X-(dT)12, where x is a hexaethylene glycol chain bridged between the 3' phosphate of one strand and the 5' phosphate of the following strand. This oligonucleotide is able to fold back on itself to form a very stable triplex. Circular dichroism spectroscopy demonstrates that berenil can bind to the triple helical structure. Spectral analysis shows that in the same ionic strength the drug bound to a double-stranded structure exhibits a conformation and an environment close to those observed in triple-stranded structure. The influence of the ionic strength on the interaction between the berenil molecule and the 36-mer is clearly demonstrated. We showed that when no NaCl salt is added in the buffer the triplex form of (dA)12-X-(dT)12-X-(dT)12 is stabilized by berenil whereas it is destabilized slightly by the dye when NaCl concentration is 1 M.
Durand
M
M
Centre de Biophysique Moléculaire Université d'Orléans, France.
Thuong
N T
NT
Maurizot
J C
JC
D001483:Base Sequence; D001665:Binding Sites; D002942:Circular Dichroism; D004247:DNA / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D004133:Diminazene / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation
C051802:triplex DNA; D004247:DNA; C003915:diminazene aceturate; D004133:Diminazene