Figure 5.

Temperature-dependent effect of IF2 mutations on ribosomal subunit assembly. Sucrose density gradient analysis (sedimentation from right to left) of the ribosomal subunits present in the extracts of cells exposed to [³H] uridine as described in Materials and Methods. Extracts of E. coli cells expressing IF2α (A and D), IF2ΔN (B and E) and IF2αΔGTPase (C and F) at 37°C (A–C) or 10°C (D–F). The A₂₆₀ (○ solid line) and the [³H] uridine incorporated (✦ dotted line) were determined for each fraction.