Table 2.

Thermodynamic parameters for the DNA duplex formations with different adjacent base pairs^a

Sequence	ΔH0 (kcal mol−1)	ΔS0 (cal mol−1K−1)	$\Delta G_{37}^0$ (kcal mol−1)	$\Delta \Delta G_{37}^0$ (kcal mol−1)b	Tm (°C)
5′-GTGTAAATGTC-3′	−55.9 ± 1.9	−160 ± 4	−6.6 ± 0.1	0	35.5
3′-CACATATACAG-5′
5′-GTGTAXATGTC-3′	−61.1 ± 1.6	−170 ± 4	−8.3 ± 0.1	−1.7	46.9
3′-CACATATACAG-5′
5′-GTGTGAGTGTC-3′	−73.4 ± 2.4	−208 ± 8	−9.1 ± 0.1	0	47.4
3′-CACACACACAG-5′
5′-GTGTGXGTGTC-3′	−69.4 ± 4.6	−189 ± 13	−10.6 ± 0.2	−1.5	56.3
3′-CACACACACAG-5′
5′-GTGTCACTGTC-3′	−62.2 ± 2.2	−174 ± 5	−8.3 ± 0.1	0	45.9c
3′-CACAGAGACAG-5′
5′-GTGTCXCTGTC-3′	−57.5 ± 2.1	−157 ± 5	−8.8 ± 0.1	−0.5	50.4c
3′-CACAGAGACAG-5′
5′-GTGTTATTGTC-3′	−66.0 ± 2.2	−188 ± 8	−6.9 ± 0.3	0	41.9
3′-CACAAAAACAG-5′
5′-GTGTTXTTGTC-3′	−62.9 ± 1.7	−175 ± 6	−8.0 ± 0.2	−1.1	47.0
3′-CACAAAAACAG-5′

^aAll experiments were carried out in a buffer containing 1 M NaCl, 10 mM Na₂HPO₄ and 1 mM Na₂EDTA at pH 7.0. Underline indicates the nucleotides forming the W₁/W₂ pair. T_m was calculated at the total strand concentration of 100 µM.

^b$\Delta \Delta G_{37}^0$ indicates the difference between the $\Delta G_{37}^0$ values of the duplexes containing X/W₂ and A/W₂ with the same adjacent base pairs.

^cThe data are derived from Table 1.