Fig. 1: Multi-NME-NTA enzyme assemblies on the human 80S ribosome.
From: Multi-protein assemblies orchestrate co-translational enzymatic processing on the human ribosome
a The ternary NatA-MAP2-80S complex around the PTE (interacting ribosomal components are shown and labeled). NatA is located at a distal site, while MAP2 binds independently and is positioned centrally on the PTE (approximately at the H24 tip). NatA binding to the distal site is maintained by the Naa15 TPR-solenoid exposing a long helix flexibly tethered to 28S rRNA expansions ES7L and ES44L. MAP2 interaction with the PTE is mainly mediated by the insert domain, which remodels 28S rRNA helix H59 as described before12. b The quaternary NatA-NAC-MAP1-80S complex (same views as in Fig. 1a). The heterodimeric NACαβ chaperone is necessary to mediate the interaction between NatA and MAP1. Overall, the NatA complex is rotated further down towards the PTE and the flexible linker is more extended while the main ribosomal contacts are maintained, as shown in Fig. 1a. NAC uses its N-terminal NACβ anchor to interact with eL19 and eL22 as before13 and its C-terminus points towards the N-terminus of MAP1. The UBA domain of NACα binds the Naa15 solenoid. The contours of the cryo-EM map are shown around the models (transparent).
