Figure 4. Ribosomes travelling along single-stranded RNA are not greatly retarded upon traversal into double-stranded structures.

PARS values >0 denote structured mRNA, <0 single-stranded. All averages plotted (± s.e.m.) are calculated across transcripts aligned by blocks of mRNA structure. The slowing of ribosomes (r_pos/r_prec30>1) relative to the preceding 30 codons starting from both the beginning of double-stranded structure (A) and 10 codons upstream of the same regions of double-stranded structure (B) are shown. In both cases, there is a degree of translational pausing observed upon the transition into folded mRNA, although some of this slowing may be caused by the presence of two or more positive charges encoded in the folded area (0≥x≤30).