Figure 5.

Yeast aspartate identity elements in the four tRNA^Arg isoacceptors. Nucleotides at position 73 (discriminator base), the anticodon loop and 10–25 bp are indicated. For comparison, the sequence of the single tRNA^Asp isoacceptor is also indicated. Aspartate identity elements are highlighted with gray squares. Note the absence of aspartate determinants from the anticodon loop of each of the four tRNA^Arg isoacceptors. tRNA₄^Arg shares two nucleotides with tRNA^Asp (open squares) in addition to U33 conserved in all tRNAs. Aspartate acceptance of each wild-type tRNA is indicated (+/−). Gains (G) or losses (L) in aspartylation capacity observed after single nucleotide mutations of tRNA₄^Arg and tRNA^Asp are indicated.