Fig. 2: Structures of six conformers from apo-AsfvTop2.

a Cryo-EM density maps for the six conformers of the full-length AsfvTop2. The selected particle percentages of conformer I, II and III are labeled. The densities for the subdomains were clearly defined at a resolution of 2.31–3.49 Å, except for the ATPase domain. Sparse densities for ATPase of conformer IIb can be seen, which indicates that these domains were not cleaved in the process of obtaining structures, but were flexible instead. The TOPRIM subdomain is not modeled in the conformer I. b High resolution cryo-EM reconstructions of the apo-AsfvTop2 cleavage core domain for the three states (I-III), with the two sub-conformers of each state superposed with each other. The distance between the Cα atoms of the Y744/Y’744 from the two α-helices 13 on the WHD subdomains of the two subunits is shown for Ia (Ia: 30.3 Å; Ib: 27.6 Å). The detailed differences between sub-conformers are shown in insets. Annotation of the helices is based on the structure-based alignment (Supplementary Figs. 5, 6). c Upper panel: Superposed structures showing major conformational changes between conformers Ia and IIa (left); Ia and IIIa (center), and IIa and IIIa (right). The TOPRIM subdomain is omitted for clarity. Lower panel: The hinge connecting helix α27 and α28 contains two non-conserved proline residues. The residues and contacts that contribute to the structural differences are labeled. d Superposition of Ia, Ib, IIa, and IIIa with the comparable crystal structures from the yeast Top2 cleavage core: pdb 1bgw (apo, TOPRIM omitted)⁴⁰, 1bjt (apo, TOPRIM omitted)⁴⁶, 3l4k (crossed-linked with dsDNA, closed state)⁶⁴, and 2rgr (complexed with dsDNA, closed state with C-gate open)⁴⁸, respectively.