AFM Study on pUC18 Plasmid by Restriction Enzyme

We utilized atomic force microscopy (AFM) to visualize pUC18 plasmid DNA and its restriction DNA fragment (EcoR I) on mica at a concentration of 1 μg/mL. The results revealed pUC18 plasmid DNA were typical closed circle annuli, and some granulo and linea aspera DNA molecule were also observed in local visual field. Then its restriction enzyme maps show us a network line image of restriction DNA fragment. Altogether, the data obtained suggests that plasmid conformations shifts make a forward step to explain mechanism of enzyme by atomic force microscope.