Interaction of a fluorescent reagent, fluorescein mercuric acetate, with nucleic acids.

摘要: Fluorescein mercuric acetate (fluorescein Hg Ac), which is a fluorescent thiol reagent, was shown to bind various nucleic acids by measuring the changes in its absorption and fluorescence properties. Up critical concentration of free fluorescein Ac (1-10(-7) M for calf thymus DNA, with 42% GC, 2-10(-7) Micrococcus lysodeikticus 72% GC) this reagent appears selectively single-stranded sections DNA. Above concentration, cooperative binding double helical DNA occurs, denatured obtained after removal bound dialysis against 1 KCl. These facts indicate that causes denaturation prior as has been case methylmercuric hydroxide. The much stronger than number total sites close base pairs both M. Furthermore, it binds thymidine, deoxyguanosine, poly(U) poly(G). Since quenching accompanies complex formation affinity markedly high indicated association constant 6.8-10(7) M(-1) can be used structural studies small amounts acids.