Loop Free-Energy Decomposition

Dimer 1

ΔG = -2.0 kcal/mol ΔH = -40.6 kcal/mol ΔS = -116.3 e.u. T_m = 18.6°C

Structural element	δδG	Information
External loop	-0.27	14 ss bases & 1 closing helices
Stack	-1.22	External closing pair is G3-C6
Stack	-1.52	External closing pair is G4-C5
Stack	-1.22	External closing pair is C5-G4
Helix	-3.97	4 base pairs
External loop	+2.27	Closing pair is C6-G3

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Dimer 2

ΔG = -1.3 kcal/mol ΔH = -33.0 kcal/mol ΔS = -95.4 e.u. T_m = -0.4°C

Structural element	δδG	Information
External loop	-0.33	26 ss bases & 1 closing helices
Stack	-1.22	External closing pair is G15-C6
Stack	-1.52	External closing pair is G16-C5
Helix	-2.75	3 base pairs
External loop	+1.75	Closing pair is C17-G4

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Dimer 3

ΔG = -2.9 kcal/mol ΔH = -58.1 kcal/mol ΔS = -166.3 e.u. T_m = 34.0°C

Structural element	δδG	Information
External loop	-0.11	12 ss bases & 1 closing helices
Stack	-0.77	External closing pair is T12-A20
Stack	-0.63	External closing pair is G13-C19
Stack	-0.64	External closing pair is A14-T18
Helix	-2.04	4 base pairs
Interior loop	-1.12	External closing pair is G15-C17
Stack	-0.64	External closing pair is C17-G15
Stack	-0.63	External closing pair is T18-A14
Stack	-0.77	External closing pair is C19-G13
Helix	-2.04	4 base pairs
External loop	+2.44	Closing pair is A20-T12