Table 1.
Properties of PR, PR20, and Selected Cluster Mutants
| PR | PRPR20-123 | PRPR20-1 | PRPR20-3 | PR20 | PR20PR-123 | PR20PR-1 | |
|---|---|---|---|---|---|---|---|
| ~Kdimer (μM) | <0.005a | 0.17 | 0.53 | 0.67 | 0.029b | 0.13 | 0.031 |
| Tm (°C) (DSC) | |||||||
| no inhibitor | 65.7c | 66.5 | 71.7b | 61.8 | |||
| ΔTm (with darunavir) | 22.4c | 11.5 | 5.3b | 16.6 | |||
| ΔTm (with saquinavir) | 19.3d | 8.1 | 2.9 | ≥11 | |||
| kinetic parameters | |||||||
| Km (μM) | 48 ± 3e | >1000 | >1071 | 124 ± 16 | 617 ± 84b | 180 ± 26 | 220 ± 30 |
| kcat (min−1) | 174 ± 3e | >450 | 213 ± 123 | 118 ± 5 | 215 ± 19b | 234 ± 15 | 112 ± 7 |
| kcat/Km (μM−1 min−1) | 3.63 ± 0.29e | 0.27 ± 0.01 | 0.16 ± 0.07 | 0.95 ± 0.15 | 0.35 ± 0.08 | 1.3 ± 0.27 | 0.51 ± 0.1 |
| inhibition constant Ki (nM) | |||||||
| darunavir | ≤0.01f | 5 ± 2.1ITC | 34.8 ± 9.7ITC | ≤1M | 41 ± 10b | 10 ± 3.2ITC | 16 ± 4ITC |
| saquinavir | 0.28 ± 0.02g | 34 ± 12ITC | 930 ± 93b | 50 ± 25M | |||
| reduced peptide bond inhibitor | 54 ± 22c | 1050 ± 50D | ≥300M | 10.8 ± 3.6M | 811 ± 52D | 48 ± 24ITC | 50 ± 14M |
| vitality | |||||||
| darunavir | 1 | 37 | 153 | 26 | 395 | 358 | 225 |
| saquinavir | 1 | 9 | 64 | 320 | |||
| Gag processingh | 1 | ~0.125 | ~0.25 | ~0.17 |
a
From ref32.
b
From ref24.
c
From ref39.
d
From ref36.
e
From ref47.
f
From refs and 50.
g
From ref51.
h
This value represents the approximate rate of processing relative to that of PR. References to published data are cited for comparison only; all other data are reported here for the first time. Ki values determined by ITC (1/Kassociation) and by kinetics using Morrison (M) and Dixon (D) plots are indicated.