Figure 7. The ribosome as a helicase.
Two mRNAs with identical sequences coding for valine are translated; they differ in the base composition of the double strand that the ribosome must unwind during translation. The rate of translation of each hairpin is measured as a function of force on the ends of the hairpins. At low force the ribosome is unwinding double strands (translation rate = Vds) at a critical force, Fc, the double-stranded helix becomes single-stranded and the rate of translation corresponds to a single strand, (Vss). The solid lines are a fit to Eq. 15. The figure is a modified form of Figure 2 from Reference 99. (Adapted with permission from ref. 99. Copyright 2011 Nature Publishing Group)