Fig. 4.

Model showing EF4 importance at high ionic strength. (A) Normal protein synthesis on polysomes; (B) high ionic strength can lead to a single stalled ribosome on a polysome; (C) upstream ribosomes are therefore blocked stopping protein synthesis on this mRNA. (D) EF4 addition mobilizes and rescues the stalled ribosome by provoking a back-translocation resulting in a pretranslocational state that can be correctly translocated by EF-G and thus allows translation of the preceding ribosomes as well.