Table 1. MM-PBSA free energy (kcal·mol⁻¹) components for the Smadn+DNA+Smadn models.

	Smad4+DNA+Smad4	Smad1+DNA+Smad1	Smad4+DNA+Smad1	Smad3+DNA+Smad3	Smad4+DNA+Smad3
Receptor	Smad4+DNA	Smad1+DNA	Smad4+DNA	Smad3+DNA	Smad4+DNA
Ligand	Smad4	Smad1	Smad1	Smad3	Smad3
ΔEele	−3453.95	−3728.48	−3855.88	−4582.86	−4724.77
ΔEvdw	−58.86	−58.27	−53.80	−87.87	−83.84
ΔE int	0.00	0.00	0.00	0.00	0.00
ΔGnp/solv	−10.18	−10.49	−10.33	−16.21	−15.61
ΔGpb/solv	3445.83	3710.30	3843.88	4577.85	4710.65
ΔGnp	−69.04	−68.76	−64.13	−104.08	−99.45
ΔGpb	−8.12	−18.18	−12.00	−8.01	−14.12
ΔTS	−59.82	−68.52	−46.62	−85.41	−78.01
ΔHbinding	−77.16	−86.94	−76.13	−109.09	−113.57
ΔGbinding	−17.34(0.18)a	−18.42(0.17)	−29.51(0.18)	−23.68(0.20)	−35.56(0.22)

^aThe values in parentheses are the calculated standard errors.

ΔG _np = ΔE _vdw+ΔG _np/solv.

ΔG _pb = ΔE _ele+ΔG _pb/solv.

ΔG_binding = ΔG_np +ΔG_pb –ΔTS.

 = ΔH_binding –ΔTS.