Interaction with H3K36me3-methylated peptides and dsDNA. (a) Ensemble of 20 best solution structures of PSIP1-PWWP domain; orange - β-sheet; blue - α-helix; gray - other. (b) Aromatic cage (green) and basic residues (magenta) shown as balls-and-sticks. Residues that have been mutated in this study are labeled. (c) Sections of the 2D 1H-15N HSQC spectrum of PWWP during the titration with H3K36me3 peptide (left panel) and dsDNA fragment (right panel). Free PWWP spectrum in black; resonances of interest are labeled. (d) Interaction surfaces for the histone peptide (left) and dsDNA (right), coded on the van der Waals surface. Grey is used for residues without data; residues with shifts larger than 10% trimmed mean + 2 σ are labeled. (e) Electrostatic potential on the solvent-accessible surface color (f) Chemical shift perturbation derived binding curves (symbols) including best fits (solid lines) for H3K36me3 peptide (left panel) and dsDNA (right panel).