Native characterization of nucleic acid motif thermodynamics via non-covalent catalysis

DNA hybridization thermodynamics is critical for accurate design of oligonucleotides for biotechnology and nanotechnology applications, but parameters currently in use are inaccurately extrapolated based on limited quantitative understanding of thermal behaviours. Here, we present a method to measure the Δ G ° of DNA motifs at temperatures and buffer conditions of interest, with significantly better accuracy (6- to 14-fold lower s.e.) than prior methods. The equilibrium constant of a reaction with thermodynamics closely approximating that of a desired motif is numerically calculated from directly observed reactant and product equilibrium concentrations; a DNA catalyst is designed to accelerate equilibration. We measured the Δ G ° of terminal fluorophores, single-nucleotide dangles and multinucleotide dangles, in temperatures ranging from 10 to 45 °C. DNA hybridisation thermodynamics parameters underlie rational design of oligonucleotides for diagnostics and nanotechnology. Here, the authors present an accurate method to measure the free energy of a given DNA structure at specific temperature and buffer conditions.