Figure 6

Structural comparison of various PWWP domains. (A) The crystal structure of the apo PWWP domain (blue) and the NMR solution structure (PDB entry: 1RI0, human HDGF PWWP domain; red) and (PDB entry: 2B8A, mouse HDGF PWWP domain; salmon) comprise a flexible hinge loop, loop2, which is shown in black for the crystal structure and green and yellow for the NMR solution structure. (B) The hinge loop is flexible in the NMR structure of the dimeric apo PWWP domain with multiple conformations (PDB entry: 2NLU, magenta), beginning from the hinge loops shown in green, similar to the crystal structure (blue and black). (C) Structural comparison of the dimeric PWWP-SMYD1 complex (black) and the dimeric apo PWWP domain (magenta). Alignment of one swapped domain shows that the other swapped domain of the PWWP-SMYD1 complex exhibits a stable conformation and a rigid domain orientation because of the newly formed αC (blue) transformed from the hinge loop, differing from the dimeric apo PWWP domain (pink) with variable orientations beginning from the hinge loop (green). (D) The main structural features of various PWWP domains (mouse HDGF, PDB: 28BA, green; MSH6, 2GFU, red; LEDGF/p75, 2M16, blue; human HDGF, 2NLU, gray; HDGF2, 3EAE, yellow; DNMT3B, 5CIU, magenta; human HDGF, 5XSL, black) are similar with the conserved β-barrel region and α-bundles in the C-terminus.