Fig. 6

The interaction of a bHLH domain with an E-box. a 3D structure of the complex of the E47 dimer and the E-box. The spatial location of residues that participate in binding to the E-box (Arg548, Asn552, Glu555, Arg556, Arg558, Asn563 and Lys585) is shown; these amino acids are marked in blue or yellow and are shown as abbreviations. “bHLH protein” mainly indicates E proteins or class II bHLH proteins. The 3D structure was obtained from the Protein Data Bank (PDB: 2YPB) and was modified using Discovery Studio 3.0 software. b Pattern chart of the interaction of the residues on the bHLH domain with the E-box. The DNA phosphate backbones are represented as filled circles, and the bases are represented as “C, A, T, and G,” such as “C 1,” which represents the cytosine at position 1 on a strand of the E-box. The residues on the bHLH domain are Arg548, Asn552, Arg558, Asn563, and Lys585. The light arrows represent the interactions between the residues and the DNA backbones, and the black arrows represent the interactions between the residues and the bases