< Back to Article
Interaction of the Transactivation Domain of B-Myb with the TAZ2 Domain of the Coactivator p300: Molecular Features and Properties of the Complex
Figure 5
Identification of the B-Myb TAD binding site on p300 TAZ2.
Panel A shows an overlay of two 15N/1H HSQC spectra of 15N labeled p300 TAZ2 (100 µM) acquired in the absence (red) or presence of equimolar unlabelled B-Myb TAD (black). The arrows highlight a number of TAZ2 signals which show significant shifts on interaction with the B-Myb TAD. Panel B contains a histogram summarizing the minimal chemical shift changes observed for backbone amide signals of p300 TAZ2 on binding to B-Myb TAD, with gaps corresponding to proline residues (1727, 1756, 1780, 1802 and 1804) or non-observable backbone amides. The combined amide proton and nitrogen chemical shift difference (Δδ) was defined according to the calculation 
where αN is a scaling factor of 0.2 required to account for differences in the range of amide proton and nitrogen chemical shifts. The reported positions of the helices in CBP TAZ2 (blue bars, [30]), together with those determined for p300 TAZ2 (yellow bars), are shown above the histogram. Panel C shows a ribbon representation of the backbone structure of the TAZ2 domain of CBP [30] and panel D a contact surface view in the same orientation. In panel E the surface view of CBP TAZ2 has been rotated by 180° about the y axis. The contact surfaces have been coloured according to the magnitude of the minimal shifts induced in backbone amide resonances of equivalent residues in p300 TAZ2 by binding of the B-Myb TAD. Residues that showed a minimal shift change of less than 0.075 ppm are shown in white, over 0.15 ppm in red, and between 0.075 and 0.15 ppm are coloured according to the level of the shift on a linear gradient between white and red. No chemical shift perturbation data could be obtained for the residues shown in yellow.
doi: https://doi.org/10.1371/journal.pone.0052906.g005