Table 1.
Inhibitory activities of (pBthTX-I)2K and analogs against SARS-CoV-2 and PLpro. The substituted Ala residue on the sequence of each peptide is indicated as red.
| Code | Peptide Sequence | MW (Da) |
EC50 (µM) |
CC50 (µM) |
SI | IC50 (µM) |
Kd (µM) |
|---|---|---|---|---|---|---|---|
| (pBthTX-I)2K | (KKYRYHLKPF)2K | 2868 | 65 ± 35 | >100 | >1.5 | 2.4 ± 0.1 | 0.9 ± 0.1 |
| A1 | (AKYRYHLKPF)2K | 2754 | >100 | >100 | n.d. | 3.5 ± 0.1 | 6 ± 3 |
| A2 | (KAYRYHLKPF)2K | 2754 | >100 | >100 | n.d. | 2.40 ± 0.03 | 7 ± 3 |
| A3 | (KKARYHLKPF)2K | 2684 | >100 | >100 | n.d. | 1.00 ± 0.03 | 6 ± 4 |
| A4 | (KKYAYHLKPF)2K | 2698 | >100 | >100 | n.d. | 2.00 ± 0.03 | 3 ± 1 |
| A5 | (KKYRAHLKPF)2K | 2684 | >100 | >100 | n.d. | 1.90 ± 0.01 | 3 ± 2 |
| A6 | (KKYRYALKPF)2K | 2736 | >100 | >100 | n.d. | 1.80 ± 0.07 | 5 ± 3 |
| A8 | (KKYRYHLAPF)2K | 2754 | 67 ± 32 | >100 | >1.5 | 2.40 ± 0.05 | n.d. |
| A10 | (KKYRYHLKPA)2K | 2716 | >100 | >100 | n.d. | 2.4 ± 0.2 | n.d. |
| A11 | (KKYRYHLKPF)4(K)2K | 5848 | 51 ± 40 | 2.0 ± 0.4 | 0.04 | 1.40 ± 0.02 | 1.0 ± 0.2 |
| A12 | (KKYRYHLKPF)2K(d-aa) | 2868 | 28 ± 14 | 58 ± 5 | 2 | 1.30 ± 0.03 | 1.6 ± 0.3 |
| CQ | -- | 7 ± 5 | 76 ± 26 | 11 | n.d. | n.d. | |
| BREQ | -- | 0.4 ± 0.3 | >10 | >25 | n.d. | n.d. | |
| Hy-a1 | IFGAILPLALGALKNLIK-NH2 | 1865 | 4 ± 3 | 81 ± 58 | 20 | >10 | n.d. |
MW = molecular weight; EC50 = effective concentration; CC50 = cytotoxic concentration; SI = selectivity index (CC50/EC50); CQ = chloroquine; BREQ = brequinar n.d. = not determined.