Table 1.

Close interatomic contacts between ligands (8,9) and the target.

FIV INa	HIV INa	CHI1019 (8)b	L-870,810 (9)b
D57	D64	X	X
C58	C65	X	X
T59	T66	X	X
H60	H67	X	X
E85	E92	X	X
T86	T93	X
D109	D116	X	X
N110	N117	X	X
G111	G118	X	X
P112	S119	X
N113	N120	X	X
F114	F121	X	X
E145	E152	X	X
N147	N155	X	X
K152	K159		X
C19	C19	X	X
A20	A20	X	X

a FIV integrase (IN) residues in close contact with the ligands (5.0 Å cutoff) and equivalent residues in HIV-1 IN. Ligands are numbered as in Fig. 4. The active site residues are shown in bold; HIV-1 residues associated with resistance to IN strand transfer inhibitors are in italics; C19 is a DNA nucleotide base, while A20 is the terminal nucleotide of the 3'- end of 3'-processed viral DNA. Numbering of nucleotides corresponds to that adopted in the crystal structure of transposable DNA bound to Tn5 transposase that was used in the present study to model the FIV proviral DNA. b Residues that show close contacts or hydrogen bond interactions with the corresponding ligand are highlighted by a cross. The pose with the highest GOLD score for each compound was considered as the best docking solution.