Loop Free-Energy Decomposition

Dimer 1

ΔG = 0.5 kcal/mol ΔH = -5.4 kcal/mol ΔS = -17.7 e.u. T_m = -140.1°C

Structural element	δδG	Information
External loop	-0.91	18 ss bases & 1 closing helices
Stack	-0.23	External closing pair is A3-T4
Helix	-0.23	2 base pairs
External loop	+1.64	Closing pair is T4-A3

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Dimer 2

ΔG = 0.4 kcal/mol ΔH = 4.4 kcal/mol ΔS = 12.0 e.u. T_m = -676.3°C

Structural element	δδG	Information
External loop	-0.95	18 ss bases & 1 closing helices
Stack	-0.23	External closing pair is A13-T14
Helix	-0.23	2 base pairs
External loop	+1.60	Closing pair is T14-A13

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Dimer 3

ΔG = -1.5 kcal/mol ΔH = -37.0 kcal/mol ΔS = -106.5 e.u. T_m = 7.0°C

Structural element	δδG	Information
External loop	-1.02	17 ss bases & 1 closing helices
Stack	-0.31	External closing pair is A9-T11
Stack	-0.62	External closing pair is A10-T10
Stack	-0.61	External closing pair is G11-C9
Stack	-0.31	External closing pair is A12-T8
Stack	-0.62	External closing pair is A13-T7
Helix	-2.46	6 base pairs
External loop	+1.95	Closing pair is G14-C6