Comparison of the kinetics of ribo-, deoxyribo- and hybrid oligonucleotide double-strand formation by temperature-jump kinetics

Abstract

The kinetics of double-strand formation were measured by using temperature-jump kinetic techniques for the DNA oligonucleotides dCA5G + dCT5G, the analogous RNA oligonucleotides rCA5G + rCU5G, and the hybrid rCA5G + dCT5G. The DNA oligonucleotides have a faster rate of recombination and a slower rate of dissociation at 12.0.degree. C than the RNA oligonucleotides; the hybrid has about the same recombination rate and a slightly faster dissociation rate than the RNA oligonucleotides. The activation energies for recombination for the DNA and RNA oligonucleotides are both near 0 kcal/mol. The difference in dissociation and recombination activation energies is consistent with the thermodynamic results obtained earlier. The relaxation process is composed of 2 exponential components for the RNA and hybrid oligonucleotides at temperatures of 12.0.degree. C and lower. One exponential component is observed for these oligonucleotides above 12.0.degree. C and for the DNA oligonucleotides at all temperatures.