Fig. 4: Organization and protomer interactions of HTNV-L apo symmetric dimer.

a HTNV-L apo symmetric dimer structure with protomer A1 shown as surface and protomer A2 shown as a cartoon. The domains are colored as in Fig. 2. The 5′vRNA end binding site and the template entry tunnel, to which the 3′vRNA binds, are indicated. b Zoom on the interaction of the C-terminal domains (CTER) in the same orientation as in (a). Protomer A1 surface is shown in transparent dark red, and its cartoon representation is in dark red. Protomer A2 is shown as a brown cartoon. Residues in interaction are shown as sticks. The C-terminal loops 2142–2151 that are crucial in the C-terminal swapping stabilization are shown in coral, with F2150 and Y2151 shown in red. c Zoom on the interaction of the endonuclease (ENDO) of protomer A1 with the CTER of protomer A2. Protomer A1 surface and cartoon are colored as in (a) with the regions that interact shown in dark green with residue numbers indicated. The CTER regions of protomer A2 that interact with protomer A1 are displayed as brown cartoons, the regions that interact are indicated. d Interaction of the lariat and the mid-link of protomer A2 with the core of protomer A1. Both protomers are colored as in (a) and shown as semi-transparent. The regions of the lariat, the mid-link, and the core that interact are respectively shown in dark orange, orange, and dark gray. Residue numbers of the regions that interact are indicated. e Interactions of the core of protomer A1, shown in gray cartoon and surface, with the core of protomer A2, shown as a light blue cartoon. The interacting residues are shown as sticks and are numbered.