Figure 1.

Frameshift suppressor tRNA^SufA6 is a derivative of ${\text{tRNA}}_{\text{CGG}}^{\text{Pro}}$. A, tertiary structure of tRNA^Pro with its anticodon depicted in cyan, anticodon loop nucleotide 37 in orange, and the mRNA in gray with the first P-site nucleotide denoted as +1; P-site codon nucleotides listed as +1, +2, and +3; and A-site codon nucleotides listed as +4, +5, and +6. B, secondary structure of the anticodon stem loop of tRNA^Pro bound to a cognate CCG codon containing three Watson–Crick base pairs. C, secondary structure of the anticodon stem loop of tRNA^SufA6 bound to a four-nucleotide slippery CCC-U codon and containing a C6-C34 wobble interaction. tRNA^SufA6 contains an extra guanosine between positions 37 and 38 (G37.5, blue).