Skip to main content
. 2010 Jul 12;49(31):6576–6586. doi: 10.1021/bi1009387

Figure 8.

Figure 8

PHD3 uses two separate surfaces to bind H3K4me3 and CYP33 RRM, and the interactions are mutually inhibitory. (A) Two surfaces with a 180° difference on the MLL PHD3 domain serve for the H3K4me3-binding site (left) and for the RRM-binding site (right). The residues whose backbone resonances were broadened out (light blue or light green) or significantly shifted (dark blue or dark green) upon complex formation are displayed on the surface. (B) Binding constants of two PHD3 mutants measured by ITC. V1617A abrogates CYP33 RRM binding affinity ∼6.2-fold but does not significantly change the affinity for H3K4me3. W1594A lacks H3K4me3 binding but does not significantly change the affinity for CYP33 RRM. Note that these two residues are located on the separate surfaces of PHD3 shown in panel A. (C) Thermodynamic box showing the binding constants for each interaction. The binding constants were measured by ITC. PHD3 (62 μM) was saturated with 540 μM H3K4me3 and then titrated with 635 μM CYP33 RRM. PHD3 (65 μM) was saturated with 200 μM CYP33 RRM and then titrated with 745 μM H3K4me3.