Solution structures of two catalytic DNAs were studied by NMR experiments.
The catalytic DNA that activates cleavage reaction of RNA phosphodiester bond, is too large to study NMR spectroscopy. Two base paired regions were synthesized for NMR study and this study was usable to assign whole catalytic DNA. The left-side stem has well stacked B-form helix but the right-side stem is unstable. The loop region doesn't have any base-paired nucleotide.
It is expected that the catalytic DNA which can assist in metallation of porphyrin ring has G-quartet structure. This assumption is from the fact that activity of this catalytic DNA is increased by K+ ion. NMR study confirmed that KCl stabilize the structure of catalytic DNA. The structure is also stabilized at 30℃.
