Number analysis of fluorescence correlation spectroscopy for the cleaving process of fluorescence labeled DNA

The cleaving process of rhodamine labeled DNA with T7-exonuclease was monitored using the fluorescence correlation method. The fluorescence correlation function, formulated so as to take into account the fluorescence efficiency of the fragment, was derived to allow analysis of the two-component system. The reaction was well represented by the two-component model, allowing monitoring of the progressive cleavage of DNA. The analysis yielded not only the size of the polymer fragment but also the efficiency of the incorporation of rhodamine and the ratio of its quantum yield in DNA and in solution.