Table 1.

Stacking and base pairing contributions to DNA polymer stability under different ambient conditions^a

[Na+], mM	Temperature, °C	A•T-containing polymer		G•C-containing polymer
		$\frac{1}{4}{\displaystyle \sum _{\text{AT},\text{AA},\text{TT},\text{TA}}}\Delta G_{\text{KL}}^{\text{ST}}$	$\Delta G_{\text{A}•\text{T}}^{\text{BP}}$	$\frac{1}{4}{\displaystyle \sum _{\text{GC},\text{GG},\text{CC},\text{CG}}}\Delta G_{\text{KL}}^{\text{ST}}$	$\Delta G_{\text{G}•\text{C}}^{\text{BP}}$
15	32/52	−1.01/−0.36b	0.57	−1.48/−1.02b	−0.11
15/100	37	−0.92/−1.32b	0.61	−1.44/−1.83b	−0.01

^aAll free energy parameters are given in kcal/mol.

^bThe two values correspond to the temperature or sodium concentration range as indicated.