Figure 5.

Substitution of the AGA rare codon of gfp with a synonymous preferred codon increased GFP activity in Pf-5. (A) Diagram to show the modification of AGA rare codons in plasmid pPROBE'-gfp(tagless). Only part of the plasmid is shown. The black bars in the above diagram above show the five AGA rare codons in the transcriptional fusion prnA::gfp(AGA). The empty bars in the lower diagram show the synonymous codons that were substituted for the AGA codons in prnA::gfp(CGC). (B) The relative GFP activity of Pf-5 containing the AGA codon-modified transcriptional fusion prnA::gfp(CGC), denoted with an asterisk, was significantly higher (student t-test, p < 0.01) than Pf-5 containing the unmodified prnA::gfp(AGA). No obvious growth (OD₆₀₀) difference was observed between strains (data not shown). Values represent the average of four replicates and error bars show the standard deviation.