Fig. 2

Crystal structure of PML B1-box multimers. a B1-box monomer. The crystallographic monomer containing residues 120–167 is shown in cartoon representation. From N- to C-terminus, the structure is colored using the rainbow scheme implemented in Pymol. I122, V123, W157, F158, and K160 are shown in stick representation. The Zn1 and Zn2 ions are shown in sphere representation. The subdomain 1 (SD1) and subdomain 2 (SD2) are bracketed. b Sequence alignment of B-box driven oligomerization. The secondary structures of PML B1-box are shown on top of the sequences. An empty arrow is used to highlight the loop-to-strand conversion during SD1-augmentation (see below, Fig. 2e). The highly conserved Zn-binding residues are highlighted with bold font. The residues, which are involved in W157-, F158-, and SD1-dimerizations, are colored in purple, yellow, and blue, respectively. The residues, which are observed in other TRIM oligomerizations, are colored in green. In particular, the conserved hydrophobic interactions in α1 helices (Supplementary Fig. 2b) are underlined. c W157-dimer. The residues W157, F138, and F152 in the dimeric cleft are shown in stick representations. d F158-dimer. The auxiliary hydrogen bonds surrounding F158–F158 are shown in dashed lines. e SD1-interface. The residues I122 and V123 that lie in the heart of SD1-augmentation are highlighted with arrows