Figure 1

Secondary structure of tmRNA and detail of the sequence upstream of the first codon of the tmRNA template. (A) Secondary structure of Escherichia coli tmRNA, including the tRNA-like domain (TLD), four pseudoknots (PK1–4), with boxes surrounding the resume and stop codons at either end of the tag template [40]. (B) Fragment of a tmRNA sequence containing the -1 triplet (GUC) and resume codon (gca). (C) Results of the KanR assay [11] for independent mutants in the sequence upstream of the resume codon (see the text). ++ denotes survival at high stringency (30 μg/ml kanamycin at 37°C); +/- denotes survival at low stringency only (15 μg/ml kanamycin at 25°C); - denotes no survival at either stringency. (D) Sequence logo displaying the consensus of all 555 natural tmRNA sequences [21, 41]. Created by Weblogo [42].