Table 1.
Dissociation constants (Kd, μM) measured by ITC and NMR for the p53 transactivation domain with CBP KIX domain.
| ITC1 | NMR2 | |
|---|---|---|
| Full p53(1-61) | 19 ± 5 | ----- |
| Full p53(13-61) | 22 ± 5 | 9.3 ± 0.5 |
| AD1 p53(14-28) | n.d.3 | 214 ± 5 |
| AD1 p53(14-28) (MLL site)4 | ----- | 211 ± 6 |
| AD1 p53(14-28) (pKID/c-Myb site)5 | ----- | 242 ± 19 |
| AD2 p53(38-61) | n.d.3 | 79 ± 4 |
| AD2 p53(38-61) (MLL site)4 | ----- | 49 ± 3 |
| AD2 p53(38-61) (pKID/c-Myb site)5 | ----- | 94 ± 6 |
| Full p53(13-57)pT18 | ----- | 1.8 ± 0.2 |
| Full p53(13-57)pS20 | ----- | 1.3 ± 0.2 |
| Full p53(13-57)pT18pS20 | ----- | 0.6 ± 0.1 |
| MLL(2840-2858) to KIX6 | 2.8 ± 0.4 | ----- |
| pKID(116-149) to KIX6 | 1.3 ± 0.02 | ----- |
| Myb(291-315) to KIX6 | 10.0 ± 2.0 | ----- |
1
ITC measurements were performed at 35°C, pH 7.0. The Kd for binding of p53(13-61) under NMR conditions (27°C, pH 6.5) is 8.5 ± 1.0 μM.
2
Kd values from NMR titrations at 27°C, pH 6.5 were obtained by global analysis.
3
n.d., not detectable by ITC
4
The titration curves of the following residues were used for the semi-global fitting: 614, 616, 620∼626, 631, 666, 669, and 670.
5
The titration curves of the following residues were used for the semi-global fitting: 595, 596, 600, 608, 609, 650, 652, 654, 655, 657, 661, and 663.
6
Kd values at 27°C, pH 7.0 (12)