Supplementary Figure 3: Structure of EBSΔC in complex with H3K4me2 peptide.

a, Superposition of the EBSΔC–H3K4me2 complex (in magenta) with the EBS–H3K27me3 complex (in silver) showing that they have similar overall structures. The two peptides are shown in a space-filling representation. b, An omit map for the H3K4me2 peptide is shown in a cyan mesh. c, Superposition of the two structures shows that Pro211 of the C-terminal loop overlaps with H3K4me2, resulting in an autoinhibition mode that blocks binding of H3K4me3 and H3K4me2. d, Enlarged view of the aromatic cage that accommodates H3K4me2. e, ITC binding curves between H3K4me3 and various EBS mutants showing that the aromatic cage is essential for H3K4me3 binding. f, ITC binding curves between EBS and a doubly methylated H3(1–35)K4me3K27me3 peptide. g, ITC binding curves between EBSΔC and a doubly methylated H3(1–35)K4me3K27me3 peptide. N values in f and g represent binding stoichiometry. The ITC experiments were repeated twice independently with similar results. h, Superposition of the EBSΔC–H3K4me2 complex (in color) with the EBS–H3K27me3 complex (in silver). The distance between H3A7 and H3K23 is measured to be 33 Å, which makes it hard to accommodate the spanning 15 residues considering the orientations of the two peptides. Thus, EBS prefers to bind H3K4me3 and H3k27me3 independently and not simultaneously.