title: [Spectral study on the interaction mechanism between thionine and calf thymus DNA].
abstract: The interaction mechanism of thionine (TH) and calf thymus DNA (CT-DNA) was studied with UV-Vis absorption spectoscopy, fluorescence spectroscopy, circular dichroism (CD), and X-ray photoelectron spectroscopy (XPS). It was demonstrated that in the pH 7.2 phosphate buffer solution, the interaction of TH and CT-DNA is in the intercalative mode. The absorbance of the absorption peak of TH decreases and the peak position shifts to the red direction. The binding constant (K) of TH with CT-DNA is 1.45x 10(4) mol x L(-1). The fluorescence intensities of TH decrease drastically with increasing the concentration of CT-DNA. The Stem-Volmer quenching constant (Ksv) was calculated to be 1.01 x 10(4) mol x L(-1). The intercalative sites are mainly located at the G-C sequences of the CT-DNA molecule through the S atom in the TH molecule according to the experimental data obtained from the fluorescence spectra and XPS analysis. The secondary structure conformation of CT-DNA is changed due to its interaction with TH.
authors.affiliation: Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
authors.forename: Jiang-yan
authors.initials: JY
authors.lastname: Du
authors.forename: Xiao-hua
authors.initials: XH
authors.lastname: Huang
authors.forename: Fei
authors.initials: F
authors.lastname: Xu
authors.forename: Yu-ying
authors.initials: YY
authors.lastname: Feng
authors.forename: Wei
authors.initials: W
authors.lastname: Xing
authors.forename: Tian-hong
authors.initials: TH
authors.lastname: Lu
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D015394:Molecular Structure; D010640:Phenothiazines / Q000737:chemistry* / Q000378:metabolism; D056951:Photoelectron Spectroscopy; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013057:Spectrum Analysis
chemical_list: D010640:Phenothiazines; D004247:DNA; C427203:calf thymus DNA; C009469:thionine