Supplementary Figure 8: Determination of the affinities of the docking fragments for p38α-2P.

(a-d) NMR titration experiments of the docking fragment of MEF2A to p38α-2P, in the absence and presence of the ATP analog. (a, b) Comparison of the ¹H-¹³C HMQC spectra (Ile-δ1 region) of 20 μM [ILV-methyl] p38α-2P with different concentrations of the MEF2A docking fragment in the absence (a) and presence (b) of 4 mM ATP analog. The arrows trace the chemical shift changes of Ile116, which exhibited the largest CSP values. (c, d) CSPs induced in the methyl resonances of Val83, Ile116, Val117, Val127, Ile131, Ile134, and Val158, which are located in and near the docking site, by titration of the MEF2A docking fragment. The dissociation constants are indicated in the plots with standard deviation estimated from fitting errors. (e, f) ITC experiments of the D-peptide to p38α-2P in the absence (e) and presence (f) of the ATP analog. The dissociation constants are indicated in the plots. The detailed experimental conditions are provided in the Online Methods.