title: Property of the M-DNA probed by a minor groove binding dye 4',6-diamidino-2-phenylindole.
abstract: Spectral properties including circular and linear dichroism (CD and LD) of M-DNA, a molecular electric wire, formed at a high Zn(2+) concentration have been studied using a minor groove binding drug 4',6-diamidino-2-phenylindole (DAPI) as a probe. As the Zn(2+) concentration increased, the magnitude of LD in the DNA absorption region decreased at pH 8.5, implying the aggregation of DNA, which is in contrast with the retained LD magnitude at pH 7.0. As the M-DNA formed, change in the secondary structure of DNA was observed by CD spectrum, which resembles that of the C-form DNA, although overall structure seemed to remain as a right handed double helix. The DAPI-DNA complex in the presence of high concentration of Zn(2+) ions at pH 7.0 exhibited the similar CD spectrum with that in the absence of Zn(2+) ion, consisting of type I, II and III. In contrast, at pH 8.5 at a high Zn(2+) concentration in which DNA is in its M-form, DNA bound DAPI produced only the type III CD, suggesting that DAPI binds at the surface of M-DNA: the presence of Zn(2+) ions prevents the minor groove binding of DAPI.
authors.affiliation: Department of Chemistry, Yeungnam University, Gyeongsan City, Gyeong-buk, 712-749, Republic of Korea.
authors.forename: Jong-Sub
authors.initials: JS
authors.lastname: Shin
authors.forename: Jong-Moon
authors.initials: JM
authors.lastname: Kim
authors.lastname: Hyun Mee Lee
authors.forename: Jae-Hyung
authors.initials: JH
authors.lastname: Kim
authors.forename: Hyosun
authors.initials: H
authors.lastname: Lee
authors.forename: Seog K
authors.initials: SK
authors.lastname: Kim
mesh_terms: D001665:Binding Sites; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007211:Indoles / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D013057:Spectrum Analysis; D015032:Zinc
chemical_list: D007211:Indoles; C007293:DAPI; D004247:DNA; D015032:Zinc