Fig. 3: The versatile nature of the Ac101/Ac144 complex is conducive to the formation of different symmetries in the nucleocapsid.
A–D View of the assemblies formed by two hetero dimers of Ac101/Ac144 in the apical and basal anchor-2 complexes (A and B, respectively) as well as in the basal C7 plug (C) and the apical C2 plug (D). In (A), the homo dimer formed by residues 112 to 219 of Ac101 as well as the upper and lower Ac101/Ac144 modules where Ac101 wraps around Ac144 are highlighted by a dotted red, blue and orange oval respectively. The * indicates the position of the α-helix formed by residues 161 to 172 which is involved in inter asymmetric unit interactions between the Ac101/Ac144 modules except for the lower Ac101/Ac144 module of the C7 plug of the basal structure. In (C), the arrow indicates a kink in the long α-helix of the upper Ac144_1 which lead to a completely different relative position of the lower Ac101/Ac144 module relative to the upper one in the basal C7 plug. E Detailed view of the interaction between asymmetric units in the basal C7 plug (named aui and aui-1) mediated by residues 161 to 172 of Ac144 of aui (in orange, * in (E) and in (A–D)). F Inter asymmetric unit interaction in the basal C7 plug only. The C-terminus of the upper Ac144_1 of aui is interacting with the lower Ac101/Ac144 module of aui+1. G Zoomed view of the region in (E). Predicted hydrogen bond-forming residues include: F170 for Ac144_1 of aui, Q255 for Ac101_1 and T126 for Ac144_1 of aui-1. H Zoomed view on the region highlighted in (C). The upper Ac144_1 N-terminus interacts with the lower Ac144_2 C-terminus by β-sheet augmentation. I Zoomed view on the region highlighted in (F). The upper Ac144_1 C-terminus (residues 270 to 290) of aui is indicated. Predicted hydrogen bond-forming residues include: N246, S281, S285 for Ac144_1 of aui, Q244, Q258 for Ac101_2 and Y234 for Ac144_2 of aui+1 respectively.
