TABLE 2.
DNA binding affinities of mutant OBD and N260 proteinsa
| Amino acid substitution |
KD for one TBS (nM) for:
|
KD ratio | |
|---|---|---|---|
| OBD | N260 | ||
| None (wild type) | 28 ± 4 | 63 ± 6 | 2.7 |
| Phosphorylation site substitutions | |||
| S120D/S123D | NA | 83 ± 13 | NA |
| T124A | NA | 78 ± 9 | NA |
| T124D | NA | 59 ± 10 | NA |
| T124E | NA | 54 ± 12 | NA |
| Class 4 substitutions | |||
| H148N | 38 ± 10 | 105 ± 4 | 2.7 |
| K167R | 30 ± 5 | 92 ± 16 | 2.7 |
| Q213H | 28 ± 2 | 59 ± 6 | 2.2 |
| L215V | 24 ± 3 | 63 ± 11 | 2.6 |
| F220Y | 25 ± 6 | 61 ± 4 | 2.4 |
| Oligomerization substitutions | |||
| F151A | 23 ± 6 | 56 ± 17 | 2.4 |
| F151Y | 25 ± 5 | 65 ± 10 | 2.7 |
| F183A | 44 ± 10 | 43 ± 1 | 1.0 |
| F151A/F183A | 28 ± 4 | 46 ± 2 | 1.6 |
a
KD values and standard deviations were obtained from at least three independent binding isotherms as described in Fig. 4 and with each data point done in triplicate. For each amino acid substitution, the ratio of the KD value of N260 over that of the corresponding OBD is indicated on the right.