Table 4. Binding energy and hydrogen bonds of viral RT to ETV-TP.

HBV strains	Binding energy (ΔG: kcal/mol)	N–H:O bonds	O–H:O bonds	pi-cation interactions
wild-type	−5.26	2	1	1
rtL180M+M204V	−4.97	0	2	0
rtL180M+A181C+M204V	−4.56	3	0	0
rtL180M+A181C+S202G+M204V	−4.37	2	0	0
rtL180M+A181C+M204V+M250V	−4.37	2	0	0

Note: RT: reverse transcriptase; ETV-TP: entecavir triphosphate.