Fig. 5. Structure of Nic96-VHH-SAN12 highlights the flexibility of the ACE1 fold.

a The structure of Nic96-VHH-SAN12. Nic96 is shown in gradient color from white to dark blue and VHH-SAN12 is shown in light blue. Helices are labeled on Nic96, along with the complementarity determining region (CDR) loops on VHH-SAN12. Boundaries of the ancestral cotamer element (ACE1) fold modules are indicated by the dashed lines. b Superposition of Nic96 with the previously solved structure (PDB: 2QX5³⁷) (shown in green). The alignment was done only in the tail module of the protein. c Superposition of the Nic96 crown module between the two structures. This structure of Nic96, shown in dark blue and the previous structure, shown in green.