Figure 3. Comparison of NMR assignments and secondary structures for the TAZ2 domains of CBP and p300.

Panel A summarises the combined differences in backbone amide (¹⁵N and ¹H), CO and Cα chemical shifts for equivalent residues in the TAZ2 domains of CBP and p300. To compensate for the increased chemical shift range of ¹⁵N and ¹³C compared to ¹H, the combined change was calculated as (Δ¹HN+(Δ¹⁵N × 0.2)+(Δ¹³Cα × 0.1)+(Δ¹³CO × 0.35))/4. In a very few cases where some of the chemical shifts were not available, the sum of the chemical shift changes was divided by the number of available shift differences. Panel B shows an alignment of the very closely related TAZ2 sequences from CBP and p300. Conservative substitutions are highlighted in an open box and non-conservative highlighted in grey. The black bars shown indicate the positions of the helices in CBP TAZ2 [30], whilst the white bars represent the positions of the helices in p300 TAZ2, which were identified by analysis of the backbone resonance assignments using the chemical shift index method [45].