Fig. 2
From: Cryo-EM structure of the human MLL1 core complex bound to the nucleosome
RbBP5 interaction with the NCP. a The cryo-EM structure of the RbBP5-NCP subcomplex (4.2 Å). The interaction interface was enlarged and shown on right. Insertion (I)-loop, Anchoring (A)-loop, and Quad-R of RbBP5, as well as the H4 tail highlighted in purple, orange, blue, and red, respectively. Histone H3 shown in green. b Interaction of Quad-R, as indicated, with DNA backbone. Red line, histone H4 tail. c Immunoblot to detect in vitro histone methyltransferase activity with the NCP as the substrate. The MLL1RWSAD complex reconstituted with wild-type and Quad-R-mutated RbBP5 indicated on top. d Immunoblot to detect in vitro histone methyltransferase activity with the NCP as the substrate. The MLL1RWSAD complex reconstituted with RbBP5 wild-type and deletion mutant proteins indicated on top. e The interface between RbBP5 and the H4 tail. Key residues on RbBP5 I-/A-loops indicated. The H4 tail (His18 to core) represented by a red line and the extended tail beyond His18 represented by a dash line. f Structural superposition of the H4 tails upon RbBP5 (cyan) and Dot1L (PDB ID: 6NJ9)31 binding. The RbBP5 and Dot1L at the interfaces enclosed by the blue and pink outlines, respectively. g In vitro pull-down assay for RbBP5 and the NCP. Ni-NTA-bound fractions were shown and His-tagged wild-type or mutant RbBP5 proteins shown on top. Immunoblot for H3 used to detect the NCP in the bound fraction. Immunoblot for H4 used as a control.
