Fig. 6

Structural details of C1-S20Δloop and C2-S20Δloop pre-40S particles. a Close-up of the atomic model of C1-S20Δloop, as seen from the 60S interface; segmented cryo-electron microscopic (cryo-EM) densities corresponding to Tsr1, Rio2, and Dim1 are shown in magenta, blue, and lime green, respectively. rRNA is in gray, and other r-proteins in pale blue. b Same view of the C1-S20Δloop model as in a, superimposed to the model of pre-40S particles purified with Ltv1 as bait (PDB 6EML)¹⁶. Spatial alignment was realized using the Matchmaker option in Chimera, using C1-S20Δloop rRNA as reference. For more clarity, only Tsr1, Rio2, and rRNA of both models are displayed. Color codes are indicated on the panel. Arrows indicate the rotation of the head of C1-S20Δloop particles compared to the PDB 6EML model. c, d Close-up of the heads of C1-S20Δloop (c) and C2-S20Δloop pre-40S particles (d), as seen from the top of the head/beak of the particles (top-left insets indicate direction of view). Segmented cryo-EM densities corresponding to Rps20, Rps3, Enp1, Asc1, and Rps10 are represented in green, red, purple, pale violet, and turquoise, respectively. rRNA is in gray, and other r-proteins in pale blue