TABLE 2.
IC50 values for the binding of the β-lactam antibiotics to the four native PBPs of S. aureus
| β-Lactam | IC50 (μM)a |
|||
|---|---|---|---|---|
| PBP1 | PBP2 | PBP3 | PBP4 | |
| Cefradine | 516 ± 69 | 180 ± 7 | 3.0 ± 0.2 | 8,250 ± 280 |
| Cephalexin | 374 ± 28 | 154 ± 4 | 4.7 ± 0.4 | 8,108 ± 304 |
| Cefepime | 1,059 ± 38 | 30.3 ± 1.5 | >7,500 | 2,346 ± 39 |
| Ticarcillin | 147 ± 15 | 22.4 ± 1.5 | 9.2 ± 0.3 | 392 ± 26 |
| Oxacillin | 42.2 ± 1.7 | 12.6 ± 0.9 | 10.4 ± 0.6 | 1,128 ± 90 |
| Ertapenem | 89.7 ± 1.8 | 7.8 ± 0.5 | 82.8 ± 6.6 | 233 ± 7 |
| Cefotaxime | 88 ± 3.9 | 4.2 ± 0.1 | 531 ± 50 | 2,567 ± 102 |
| Ceftriaxone | 100 ± 6 | 3.8 ± 0.1 | 71.9 ± 5.3 | 8,906 ± 321 |
| Imipenem | 2.7 ± 0.1 | 1.3 ± 0.1 | 3.9 ± 0.3 | 85.4 ± 2.4 |
| Cefdinir | 104 ± 4 | 1.0 ± 0.1 | 2.5 ± 0.3 | 126 ± 6 |
a
IC50 reflects the concentration of β-lactam antibiotic that reduces the anisotropy (in the case of PBP1, PBP2, and PBP3) or initial anisotropy velocity (in the case of PBP4) of 1 μM Bocillin by 50%. The indicated uncertainties reflect the standard deviation of the experimental anisotropy data points in Figures 3 and S3 from the corresponding fitted curves.