Dynamic structure of DNA complexes. Fluorometric measurement of hydrogen-deuterium exchange kinetics of dna-bound ethidium dimer and acridine-ethidium dimer.
The hydrogen-deuterium (H-D) exchange kinetics of free and DNA-bound ethidium dimer and acridine-ethidium heterodimer were measured by stopped flow using fluorescence detection. This technique allowed a very accurate measurement of the exchange process. The H-D exchange kinetics were measured in various environments. In some cases, it was observed that the H-D exchange was much faster than the dissociation rate of dimer-DNA complexes. This showed that the exchange was taking place directly from the bound state. Furthermore, the action of a catalyst (imidazolium ion) on the rate of H-D exchange showed that a dynamic structural fluctuation of the ligand in its DNA complex was a necessary step on the exchange process.
D000166:Acridines; D000588:Amines; D002384:Catalysis; D004247:DNA; D003903:Deuterium; D004305:Dose-Response Relationship, Drug; D004996:Ethidium; D006859:Hydrogen; D007700:Kinetics; D009994:Osmolar Concentration; D013050:Spectrometry, Fluorescence
D000166:Acridines; D000588:Amines; D006859:Hydrogen; D004247:DNA; D003903:Deuterium; D004996:Ethidium