Extended Data Fig. 7: Peripheral RNA heterogeneity of the RTIC conformers.

a, Tiled views of eight conformations emerging from 3D classification of RTIC. Each class is numbered and class 7 was used for the global RTIC reconstruction. b, Superposition of the eight classes from a. The main areas of RNA heterogeneity are focused on the orientations of vRNA H2, H1 and the connection loop, and the tRNA. With no stabilizing protein contacts, vRNA H2, H1, and the tRNA sample a wide range of conformations, limiting the resolution of the global map. c, Additional RTIC models built into classes 3 (tan) and 4 (blue). The models for the tRNA, vRNA H1, and vRNA H2 were all derived from the global RTIC model and treated as rigid bodies for model building. The connecting loop was not built in these models as the density for this region was not clear in these maps, though there is reasonable density to model a loop near H1. Junctions between the helices serve as hinges that allow movement of the independent domains. The main text global RTIC model (grey) is included as a comparison. d, The vRNA and tRNA helices treated as rigid bodies for modelling are shown in bold. Hinge points for each helix are highlighted with grey circles and serve as points of flexibility for the RTIC.