Multiple binding modes for Hoechst 33258 to DNAT Stokke and HB Steen
Two binding modes for the bisbenzimidazole Hoechst 33258 to native DNA at physiological conditions have been distinguished. Type 1 binding, which dominated at low dye/phosphate ratios (D/P less than 0.05) or low dye concentrations, had a high quantum yield of fluorescence with maximum emission at 460 nm. Binding of the dye at type 2 sites (0.05 less than D/P less than 0.4) lead to quenching of fluorescence from type 1 bound dye, presumably by nonradiative energy transfer. Fluorescence quantum yield of type 2 bound dye was low (phi = 0.05-0.1) and it peaked around 490 nm. At D/P greater than 0.4, the dye/DNA complex precipitated. This was caused by an additional dye-DNA interaction that was strongly cooperative. The anomalous dispersion of the refractive index of the complex changed abruptly around D/P = 0.4, indicating that the precipitating dye-DNA interaction involved strong electronic interaction between dye molecules. Hoechst 33258 precipitated polynucleotides irrespective of strandedness and base composition when dye concentration was raised above 1 X 10(-5) M. In the presence of 25% ethanol, type 2 binding to DNA did not occur, whereas the binding constant for type 1 binding (kappa = 2 X 10(3) M-1) was about two orders of magnitude smaller than in physiological buffer. DNA was not precipitated by high concentrations of Hoechst 33258 in 25% ethanol.
Volume 33,
Issue 4,
pp. 333-338,
04/01/1985
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M. Saito, M. Kobayashi, S.-i. Iwabuchi, Y. Morita, Y. Takamura, and E. Tamiya DNA Condensation Monitoring after Interaction with Hoechst 33258 by Atomic Force Microscopy and Fluorescence Spectroscopy J. Biochem., December 1, 2004; 136(6): 813 - 823. [Abstract] [Full Text] [PDF] |
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A. Adhikary, V. Buschmann, C. Muller, and M. Sauer Ensemble and single-molecule fluorescence spectroscopic study of the binding modes of the bis-benzimidazole derivative Hoechst 33258 with DNA Nucleic Acids Res., April 15, 2003; 31(8): 2178 - 2186. [Abstract] [Full Text] [PDF] |
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J. van de Sande, N. Ramsing, M. Germann, W Elhorst, B. Kalisch, E von Kitzing, R. Pon, R. Clegg, and T. Jovin Parallel stranded DNA Science, July 29, 1988; 241(4865): 551 - 557. [Abstract] [PDF] |
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