TABLE 2.

Inhibition characteristics and thermodynamic parameters for the binding of inhibitors to the wild-type subtype B, wild-type C-SA, and V82A and V82F I84V mutant HIV-1 PRs

HIV-1 PR and inhibitor	Inhibition characteristic (nM)a		Thermodynamic parameter
	IC50	Ki	Kd (nM)	▵G (kcal/mol)	▵H (kcal/mol)	−T▵S (kcal/mol)
Wild-type subtype Bb
Saquinavir			0.40	−12.80	1.90	−14.70
Ritonavir			0.03	−14.40	−3.70	−10.70
Indinavir			0.48	−12.70	2.10	−14.80
Nelfinavir			0.26	−13.10	2.60	−15.70
Wild-type C-SA
Saquinavir	0.12 (1)	0.62 (1)	0.84	−12.40	6.40	−18.80
Ritonavir	1.25 (1)	0.50 (1)	0.21	−13.20	−4.20	−9.10
Indinavir	3.02 (1)	0.49 (1)	0.95	−12.30	2.70	−15.00
Nelfinavir	2.34 (1)	0.52 (1)	0.30	−13.00	4.10	−17.10
V82A mutant
Saquinavir	0.28 (2.3)	0.97 (1.6)	1.85	−12.00	5.50	−17.50
Ritonavir	6.26 (5.0)	1.08 (2.2)	2.00	−11.90	−2.20	−9.70
Indinavir	26.01 (8.6)	1.20 (2.4)	12.70	−10.80	2.90	−13.70
Nelfinavir	2.87 (1.2)	0.90 (1.7)	0.66	−12.50	4.30	−16.90
V82F I84V mutant
Saquinavir	12 (100)	29 (47)	98	−9.60	0.80	−10.40
Ritonavir	250 (200)	97 (194)	230	−9.10	0.60	−9.60
Indinavir	1,500 (497)	219 (447)	450	−8.70	3.80	−12.50
Nelfinavir	240 (103)	56 (108)	110	−9.50	4.00	−13.50

^aThe ratio of the value for the mutant to the value for the wild type is given in parentheses for the variant PRs.

^bThermodynamic parameters for the wild-type HIV-1 subtype B PR were taken from Velazquez-Campoy et al. (29) for comparison purposes.