Figure 1.

Sucrose gradient sedimentation profiles of 70S ribosomes in the presence and absence of IF3. (a) Sedimentation profile of 70S ribosomes through a 10–30% sucrose gradient in 10 mM Mg²⁺. (b) Sedimentation profile of 70S ribosomes incubated with a 10-fold molar excess of IF3 through a 10–30% sucrose gradient in 10 mM Mg²⁺. The 70S peak is no longer present and the two peaks correspond to the 30S⋅IF3 complex and 50S subunits.