Analysis of the interaction of Brd2 BD2 with H4-AcK12 peptide by NMR. (A) Overlay of the 15N-HSQC spectra of Brd2 BD2 in free of H4-AcK12 peptide (red) and in the presence of H4-AcK12 peptide (cyan). Five of the most perturbed residues (L334, G335, L336, Y339, and Y381) and the five negative-charged aspartate residues (D330, D338, D341, D385 and D387) were denoted. (B) Binding constant was determined by monitoring the combined chemical shift perturbations (Δδ
) of four most perturbed and not severely-overlapped residues (G335, L336, Y339 and Y381) as a function of concentrations of H4-AcK12 peptide.