Figure 4.
Ribbon representation of the Sulfolobus solfataricus exosome including a Corey–Pauling–Koltun model of the RNA bound in the structure. A possible path for RNA substrates is indicated by a magenta-coloured line. In this model, the 3′ end of the RNA substrate is recruited by the S1 pore of the Rrp4/Csl4 cap and then threaded through the neck of the central channel to the processing chamber, where it binds at one of the active sites and is degraded in a processive manner. Csl4, cep1 synthetic lethality; Rrp, ribosomal RNA processing factor.