Figure 2

Structure of the BRD4 ET domain with JMJD6 complex. (A) The backbone atom superposition of the final 20 NMR-derived structures of the complex. The figure shows the BRD4 ET domain residues 601–683 (blue) and the JMJD6 peptide residues 84–96 (yellow). The terminal residues, which are structurally disordered, are omitted for clarity. (B) Electrostatic potential surface representation of the BRD4 ET domain bound to the JMJD6 peptide (yellow). The orientation is the same as (A). The electrostatic potential calculation was performed in PyMol (v1.8) using the APBS modules. (C) Ribbon depiction of the lowest energy NMR structure of the BRD4 ET domain/JMJD6 peptide complex with the same orientation of (A). (D) The stick diagram showing side-chain interactions of negative charged residues in the BRD4 ET domain α1-α2 loop (D650, E651, E653 and E657) with positive charged residues of JMJD6 peptide (K84, K91 and R95). ET domain residues involved in peptide binding are labeled and colored in blue, and JMJD6 residues in yellow, the orientation is the same as (A). (E) Expanded diagram of key hydrophobic side-chain interactions from the α-helix JMJD6 peptide to the hydrophobic binding core of the BRD4 ET domain surrounded by α1, α2 helices and α1-α2 loop. The peptide in the stick representation is depicted as in the ribbon diagram on (D). The peptide elements are colored in yellow and red. The protein hydrophobic side-chains are colored in blue. (F) Ribbon depiction of the crystal structure of the JMJD6 with the orientation of the α6 helix facing front (colored in yellow).