Table 1.

Melting Transition Temperatures (T_m (°C)) and Free Energies (−ΔG° (kcal/mol)) for Complexes of Linear and Circular Purine-Rich DNAs with Complementary Pyrimidine DNA and RNA Single Strands at pH 7.0 (Lines Indicate Watson–Crick Complementarity, Dots Hoogsteen Complementarity, and Arrows 5′ to 3′ Directionality^a

ligand	complex	Tm(°C)a,b	-ΔG°37b (kcal/mol)	-ΔG°60b (kcal/mol)
DNA target
linear 12mer		56.9	14.2	8.4
1		68.4	16.9	11.6
2		71.0	17.3	12.0
3		61.9	12.4	9.4
RNA target
linear 12mer		58.9	15.6	8.3
1		65.3	14.5	10.4
2		69.2	15.4	11.2
3		64.3	15.3	10.3

^aConditions: 10 mM Mg²⁺, 100 mM Na⁺, 10 mM Na·PIPES (pH 7.0), at 4.0 μM total DNA concentration.

^bUncertainties in T_m values and in free energies are estimated at ±1.0 °C and ±15%, respectively.