Thermodynamic contributions of single internal rA · dA, rC · dC, rG · dG and rU · dT mismatches in

The thermodynamic contributions of rA · dA, rC · dC, rG · dG and rU · dT single internal mismatches were measured for 54 RNA/DNA duplexes in a 1 M NaCl buffer using UV absorbance thermal denaturation. Thermodynamic parameters were obtained by fitting absorbance versus temperature profiles using the curve-fitting program Meltwin. The weighted average thermodynamic data were fit using singular value decomposition to determine the eight non-unique nearest-neighbor parameters for each internal mismatch. The new parameters