A, size exclusion profiles of E-box DNA in the absence (red) and presence of Max and unmodified (blue) and PAK2-phosphorylated (green) MycWT. a.u., arbitrary units. B and C, ITC titration curves of unphosphorylated (B) and phosphorylated (C) MycWT binding to Max at pH 7.4. D and E, ITC-derived thermodynamic parameters of Myc bHLH-LZ variants binding to Max at pH 7.4 (D) and pH 6.5 (E). The asterisk indicates 2:1 binding stoichiometry. F and G, flat profiles of ITC-integrated heat data of 8 μm MycS373D/T400D titration to 80μm Max (F) and 8 μm MycWT titration to 80 μm Omomyc (G), revealing no interaction between the proteins in vitro. All ITC experiments were performed with MycWT, MycWT-2P, Mycmutant, and Omomyc as titrants and Max as analyte.