Table S1.
Binding affinities for a range of NTD substrates
| Protein | Molecular weight, kDa | PI | KD, μM | Protein type |
| α-Casein | ∼23 | 4.7 | 107 ± 23 | IDP |
| PhoA1-121 (P1) | 12.8 | 9.0 | 281 ± 73 | Unfolded |
| PhoA119-243 (P2) | 12.3 | 5.3 | 268 ± 62 | Unfolded |
| PhoA244-349 (P3) | 11.5 | 6.8 | 243 ± 42 | Unfolded |
| PhoA349-471 (P4) | 12.9 | 5.0 | 181 ± 56 | Unfolded |
| PhoA1-62 | 6.4 | 8.3 | 311 ± 57 | Unfolded |
| PhoA425-471 | 4.9 | 4.9 | 255 ± 35 | Unfolded |
| Sic1 | 9.6 | 12.2 | 342 ± 88 | IDP |
| c-Jun | 13.4 | 5.3 | 289 ± 58 | IDP |
| Src1-85 | 8.4 | 10.2 | 396 ± 74 | IDP |
| p13 | 1.3 | 4.3 | 320 ± 60 | Peptide |
Affinities quantified from fits of chemical shift changes in titration spectra of U-[1H,15N] NTD as a function of added substrate. All measurements were at 55 °C. IDP, intrinsically disordered protein.