Table 1.
Ability of small molecules to re-couple troponin in thin myofilaments measured by in vitro motility assay.
| Drug | Coupling Difference (Initial Screen E180G) | E180G EC50 % Motility Difference, μM | Other mutations | EC50 Hsp90 inhibition assay |
|---|---|---|---|---|
| EGCG | 23.0 | 59 μM | see Figure 1 | |
| Silybin(racemic mixture) | 12.0 | 47 μM | E54K, E99K | |
| 1 | 1.0 | |||
| 2 (23h) | 27.0 | 30 μM | 22 μM | |
| 3 (27a) | 8.0 | 14 μM | ||
| 4 (23p) | 27.0 | 34 μM | >100 μM | |
| 5 | 2.0 | |||
| 6 | 1.0 | |||
| 7 (27c) | −11.0 | 67 μM | E54K, E99K | 32 μM |
| 8 (27p) | No Effect | 38 μM | ||
| 9 (23q) | 20.0 | 35 μM | >100 μM | |
| 10 | No Effect | |||
| 11 (10c) | 7.0 | E54K | >100 μM | |
| 12 (23f) | −1.0 | No Effect | 63 μM | |
| 13 | No Effect | |||
| 14 | 17.0 | 36 μM | ||
| 15 (10j) | 13.0 | 19 μM | ||
| 16 (27h) | 6.0 | 31 μM | 8 μM | |
| 17 (23b) | 3.5 | 58 μM | ||
| 19 (27g) | 24.0 | 21 μM | ||
| 20 | 2.0 | |||
| 21 (11d) | 25.0 | 14 μM | ||
| 22 | 7.0 | |||
| 23 (23a) | 9.0 | 98 μM | ||
| 24 | 8.0 | 24.5 μM | ||
| 26 (7a) | 26.0 | E54K | ||
| 27 (31d) | 4.0 | 55 μM | ||
| 28 (10c) | 4.0 | >100 μM | ||
| Epicatechin (EC) | 69 | |||
| Epigallocatechin (EGC) | 62 | |||
| Gallocatechin (GC) | 68 | |||
| Epicatechin Gallate (ECG) | 8 | |||
| Silybin A | 5 | G159D | ||
| Silybin B | 55 | 39 μM | G159D | |
| Dehydrosilybin A | 3 | G159D | ||
| Dehydrosilybin B | 62 | 47 μM | G159D | |
| Isosilybin | 4 | |||
| Silychristin | 35 | |||
| Silydianin | 20 | |||
| Taxifolin | 60 | |||
| Quercetin | 51 | 8 μM | ||
| Resveratrol | 63 | |||
| Novobiocin | 46 | |||
| Pterostilbene | 50 | |||
| Sissotrin | 30 | |||
| W-7 | 50 | |||
| Omecamtiv Mecarbil | 0 |
Test system as shown in Figure 2. Compounds 1–28 were synthesized by Blagg and Khandelwal; their corresponding identification numbers in the original paper are given in brackets and the structures are shown in the supplement (Khandelwal et al., 2013). Difference between motility (%) in phosphorylated and unphosphorylated forms of thin filaments (and EC50, when measured) with TPM1 E180G HCM mutation are shown. Other mutations also used in this test are E54K, TPM1 E54K DCM mutation; E99K, ACTC E99K HCM mutation and G159D, TNNC1 G159D DCM mutation. Compounds highlighted in green are effective re-couplers. Compounds highlighted in red indicate reverse re-coupling where Ca2+-sensitivity of the phosphorylated Tn I is greater than that of the dephosphorylated Tn I. In orange is the reverse re-coupler #7. For comparison the last column shows the effectiveness of these compounds in an assay for Hsp90 inhibition; effective Hsp90 inhibitors are highlighted in green and EC50 is given when measured (Khandelwal et al., 2013).