CONTROL OF TRANSLATION BY MESSENGER-RNA SECONDARY STRUCTURE IN ESCHERICHIA-COLI - A QUANTITATIVE-ANALYSIS OF LITERATURE DATA

Translational efficiency in Escherichia coli is strongly controlled by the secondary structure of the mRNA in the translational initiation r egion. We have previously shown that protein production from the coat- protein gene of RNA bacteriophage MS2 is directly related to the fract ion of mRNA molecules in which the ribosome binding site is unfolded. This fraction is dictated by the free energy (Delta G(f)(0)) of the lo cal secondary structure. We now present a similar analysis of publishe d data on four other ribosome binding sites. The results conform quant itatively to the same relationship as found for the MS2 coat-protein g ene. The efficiency of translation is determined by the overall stabil ity of the structure at the ribosome binding site, whether the initiat ion codon itself is base-paired or not. Structures weaker than -6 kcal /mol usually do not reduce translational efficiency. Below this thresh old, all systems show a tenfold decrease in expression for every -1.4 kcal/mol, as predicted from theory.