Table 1.
Thermodynamic parameters of binding for each protease variant to SQV, APV, and DRV at 20ºC
| Variant | Ka(M−1) | Kd(nM) | KdRatio | ΔH kcal mol−1 | −TΔS kcal mol−1 | ΔG kcal mol−1 |
|---|---|---|---|---|---|---|
| SQV | ||||||
| wild typea | (2.0 ± 0.1) × 109 | 0.50 ± 0.03 | 1 | 3.6 ± 0.1 | −16.1 ± 0.1 | −12.5 ± 0.1 |
| Flap+(I54V)b | (5.7 ± 0.1) × 106 | 170 ± 4 | 350 | 12.9 ± 0.1 | −21.9 ± 0.1 | −9.1 ± 0.1 |
| I54V | (1.1 ± 0.6) × 109 | 0.93 ± 0.6 | 1.9 | 7.0 ± 0.2 | −19.1 ± 0.4 | −12.1 ± 0.3 |
| Flap+(I54A) | (1.1 ± 0.1) × 106 | 880 ± 40 | 1800 | 10.7 ± 0.3 | −18.8 ± 0.3 | −8.1 ± 0.1 |
| I54A | (4.3 ± 0.3) × 107 | 23 ± 2 | 47 | 8.0 ± 0.1 | −18.2 ± 0.1 | −10.2 ± 0.1 |
| G48V | (5.8 ± 0.3) × 107 | 17 ± 1 | 34 | 6.9 ± 0.1 | −17.3 ± 0.1 | −10.4 ± 0.1 |
| APV | ||||||
| wild typec | (2.6 ± 1.3) × 109 | 0.39 ± 0.20 | 1 | −7.3 ± 0.9 | −5.3 ± 0.9 | −12.6 ± 0.3 |
| Flap+(I54V)b | (7.6 ± 0.1) × 108 | 1.31 ± 0.01 | 3.3 | 3.3 ± 0.5 | −15.2 ± 0.5 | −11.9 ± 0.1 |
| I54V | (7.4 ± 0.4) × 109 | 0.14 ± 0.01 | 0.3 | −7.2 ± 0.5 | −6.0 ± 0.5 | −13.2 ± 0.1 |
| Flap+(I54A) | (1.0 ± 0.1) × 109 | 0.99 ± 0.09 | 2.5 | −7.0 ± 0.8 | −5.1 ± 0.8 | −12.1 ± 0.1 |
| I54A | (1.5 ± 0.1) × 109 | 0.66 ± 0.04 | 1.7 | −7.3 ± 0.2 | −5.0 ± 0.2 | −12.3 ± 0.1 |
| G48V | (2.9 ± 0.3) × 109 | 0.34 ± 0.03 | 0.9 | −7.4 ± 0.5 | −5.3 ± 0.5 | −12.7 ± 0.1 |
| DRV | ||||||
| wild typec | (2.2 ± 1.1) × 1011 | 0.0045 ± 0.002 | 1 | −12.1 ± 0.9 | −3.1 ± 0.9 | −15.2 ± 0.3 |
| Flap+(I54V)b | (3.9 ± 0.7) × 1010 | 0.026 ± 0.005 | 5.7 | 2.0 ± 0.6 | −16.2 ± 0.6 | −14.2 ± 0.1 |
| I54V | (1.2 ± 0.3) × 1011 | 0.0083 ± 0.002 | 1.9 | −8.9 ± 0.3 | −5.9 ± 0.4 | −14.8 ± 0.1 |
| Flap+(I54A) | (1.4 ± 0.2) × 1010 | 0.074 ± 0.01 | 16 | −7.0 ± 0.4 | −6.6 ± 0.4 | −13.6 ± 0.1 |
| I54A | (9.5 ± 0.1) × 1010 | 0.011 ± 0.001 | 2.3 | −10.6 ± 0.1 | −4.1 ± 0.1 | −14.7 ± 0.1 |
| G48V | (1.4 ± 0.1) × 1010 | 0.073 ± 0.004 | 16 | −10.3 ± 1.6 | −3.3 ± 1.6 | −13.6 ± 0.1 |