Table 1.

Summary of ITC measurements

Histone and proteinKd (μM)ΔH (kcal/mol)N*
H3-K9me3
 PHD1.47 ± 0.07−6.36 ± 0.301.02 ± 0.04
 TTD1.75 ± 0.19−8.35 ± 0.061.17 ± 0.08
 TTD-PHD0.37 ± 0.01−12.10 ± 0.671.00 ± 0.05
 R295A/R296A3.27 ± 0.17−8.22 ± 0.052.06 ± 0.04
 S298ph§8.99 ± 0.65−10.52 ± 0.111.49 ± 0.06
 TTD+PHD1.99 ± 0.28−8.27 ± 0.282.16 ± 0.01
Unmodified H3
 PHD1.73 ± 0.09−6.89 ± 0.070.99 ± 0.01
 TTDN/DN/DN/D
 TTD-PHD1.04 ± 0.20−6.94 ± 0.571.02 ± 0.05
H3-R2me2a**
 PHD12.70 ± 1.57−3.22 ± 0.110.97 ± 0.02
 TTD-PHD10.29 ± 2.93−4.41 ± 0.260.91 ± 0.04
H3-R2me2-K9me3
 TTD1.98 ± 0.82−7.41 ± 0.70−1.17 ± 0.05
 TTD-PHD3.43 ± 0.02−8.05 ± 0.19−1.05 ± 0.02
H3-T3ph-K9me3
 PHDN/DN/DN/D
 TTD6.66 ± 0.51−6.51 ± 0.161.12 ± 0.01
 TTD-PHDN/DN/DN/D
H3-K9me3-S10ph
 PHD2.69 ± 0.22−5.90 ± 0.130.99 ± 0.01
 TTD5.81 ± 0.89−7.20 ± 0.421.16 ± 0.02
 TTD-PHD2.50 ± 0.13−6.14 ± 0.111.04 ± 0.05
H3-A1ac††-K9me3
 PHDN/DN/DN/D
 TTD1.79 ± 0.61−8.34 ± 0.581.15 ± 0.02
 TTD-PHDN/DN/DN/D
  • N/D, not detected.

  • *Binding stoichiometry.

  • Arg-295 and Arg-296 substituted to alanine in TTD-PHD.

  • Because the binding stoichiometry was not 1:1 or could not be determined from the ITC data, the apparent dissociation constants calculated on the basis of an assumption of 1:1 stoichiometry are not accurate.

  • §Phosphorylated Ser-298 in TTD-PHD.

  • An equimolar mixture of isolated TTD and PHD finger was the titrant.

  • No or very weak binding was observed in the ITC experiment.

  • **NG-NG asymmetric dimethylated arginine.

  • ††Acetylation of N-terminal amide.