The Hairpin Ribozyme: Discovery and Development for Gene Therapy

The minimum catalytic center of (-)s TRSV was identified, biochemically characterized and named the hairpin ribozyme (1 , 2 ). Following initial identification of the minimum catalytic sequence, we identified a trans -catalytic reaction and biochemically characterized this reaction. The minimum sequence for catalytic activity was found to be a 50 nucleotide (nt) ribozyme and a 14 nt substrate. This was determined by modeling and cut-down experiments. A 50 nt catalytic RNA could cleave a 14 nt substrate RNA and the reaction occurred in trans. The reaction proceeded without depletion of the 50 nt RNA component, and therefore was catalytic. It had true Michaelis-Menten kinetics allowing determination of K_M ,k_cat , energy of activation, Mg²⁺ dependence, and the pH optima.