Table 2. MM/GBSA binding energies of GA A and GA Df to pG4DNA and residues involved in the G4-ligand interactions.

Triterpenoids	ΔVDWa (kcal/mol)	ΔSURb (kcal/mol)	ΔGBELEc (kcal/mol)	ΔTOTd (kcal/mol)	Residues involved in H-bonding	H-bond length (Å)
GA A	-49.47 ± 1.57	-3.93 ± 0.04	29.94 ± 1.61	-23.46 ± 1.70	DG 11	2.21
GA Df	-44.76 ± 2.17	-3.84 ± 0.04	35.28 ± 2.51	-13.32 ± 2.21	DG 11	2.12
					DA 3	2.74
a ΔVDW is the change in van der Waals energy in the gas phase upon complex formation. b ΔSUR is the change in energy due to the change in surface area upon complex formation. c ΔGBELE is the change in GB reaction field energy + gas phase electrostatic energy upon complex formation. d ΔTOT = ΔVDW + ΔSUR + ΔGBELE is the change in potential energy in water upon complex formation.
Abbreviations: MM-GBSA, molecular mechanics/ generalized Born surface area; DA 3, adenine base of G-quadruplex DNA at position 3; DG 11, guanine base of G-quadruplex DNA at position 11; GA, ganoderic acid.