Table 4.
Affinity of mirror-image EETI-II–based binders (compounds 1–7) to 12CA5
| Competitor | IC50 (FP) | Kd (FP) | Kd (BLI) |
| YPYDVPDYA (HA epitope) | 174 ± 28 nM | 8 nM | — |
| GcßypyefdephßckqdsdclaGckcGpnGfcG 1 | 10 ± 1 μM | 460 ± 100 nM | 50 nM (22–120 nM) |
| GcßGypyeydweßckqdsdclaGckcGpnGfcG 2 | 19 ± 1 μM | 870 ± 100 nM | — |
| GcßGGypfevddßckqdsdclaGckcGpnGfcG 3 | 34 ± 1 μM | 1.6 ± 0.3 μM | — |
| GcßGypleydsvßckqdsdclaGckcGpnGfcG 4 | 36 ± 2 μM | 1.7 ± 0.4 μM | 45 nM (18–140 nM) |
| GcßvlhypeeGdßckqdsdclaGckcGpnGfcG 5 | 50 ± 2 μM | 2.3 ± 0.5 μM | 85 nM (36–250 nM) |
| GcßaldyplevdßckqdsdclaGckcGpnGfcG 6 | 98 ± 8 μM | 4.5 ± 1 μM | — |
| GcßypeekdpysßckqdsdclaGckcGpnGfcG 7 | 165 ± 11 μM | 6.1 ± 2 μM | — |
All cysteines were present as disulfide bonds. All compounds shown were characterized by FP competition binding assay; select compounds were characterized by both FP and BLI. Uncertainties in IC50 values (FP) are from regression analysis, except for the HA epiotope, where the uncertainty is the SD of three independent measurements. Relative Kd values (IC50 values) were converted to Kd values using the experimentally determined Kd of the HA epitope (8 nM). Uncertainties in Kd values were determined by propagation of uncertainties in IC50 values. For BLI measurements, ranges of Kd values are reported to account for scatter in the kon and koff values obtained from individual kinetic traces. Dash denotes not determined.