Figure 5. Assembly Scheme for the SSU.
, The early- and late-binding MRPs are illustrated in (A) and (B), respectively, from two points of view, one rotated 180° with respect to the other. The 12S rRNA is shown with light blue spheres representing individual residues. Proteins are shown as cartoon structures within transparent surfaces.
(A) Early MRPs are shown in magenta and, for the group containing mS27, in red. uS5m is shown in a salmon color to indicate that it bridges the upper and lower groups, which are outlined by dashed circles and illustrated in greater detail in Figure S5.
(B) Late-binding proteins are shown in blue along with the early proteins as in (A).
(C) The assembly scheme for the SSU showing protein-protein interactions between individual or grouped polypeptides, with their longer standard names truncated to numbers for simplicity. Heavy dashed lines indicate interaction surface areas greater than 1,000 Å2 (see Figure S4), while lighter dashed lines indicate interactions between 1,000 Å2 and 350 Å2. mS22, mS31, mS35, mS39, and bS1m are shown in boldface brown type, since they are early-binding proteins lacking extensive RNA contacts. Since they depend on other proteins for assembly, they may be considered secondary binding proteins associated with the indicated early clusters. uS6m and mS38 are shown as independent proteins with variable association with the mS26 group but did not yield sufficient proteomic data for definitive kinetic assignment.