Supplementary Figure 5: The helical repeat proteins Utp20 and Rrp5 chaperone rRNA in the 5’- and central domain.
From: The complete structure of the small-subunit processome
(a and b) Two views of a composite cryo-EM density map consisting of the 6 Å low-pass filtered overall map 2 and the 7.2 Å central domain map. The density is colored as in Figure 1 but with the pre-18S RNA colored in pale-green. Helices (h8, h10, h24, h44) and expansion segments (ES3A, ES3B) of the 18S rRNA are labeled next to the corresponding density. In (b) the density for the tetratricopeptide repeat (TPR) of Rrp5 is shown transparent with the docked crystal structure (PDB 5C9S). (c) Cryo-EM density from the central domain map with molecular fit of the TPR repeat crystal structure of Rrp5 (PDB 5C9S), shown as cartoon. The concave interface serves as binding platform for 18S rRNA helix 24 (h24, in green).
