Schematic representation of the +1-peuA′-flag (A) and +39-peuA′-flag (B) DNA fragments.

Each of these DNA fragments includes a nucleotide sequence corresponding to the peuA 5′-UTR from the +1 or +39 sites and the nucleotide sequence for the N-terminal 99 amino acid residues (in gray), in addition to a T7 promoter and a FLAG tag preceding the stop codon (TAA). The secondary structures of the 5′-UTRs of the +1 transcript (A) and the +39 transcript (B) of peuA are shown, both of which were predicted by the CentroidFold software ( The RBS and start codon of peuA mRNA are boxed in the secondary structures.