Fig. 2.
M. mobile LeuRS exhibits pretransfer editing activity. Reaction mixtures contained 10 μM M. mobile tRNALeu or a tRNA analog with 2′-deoxyadenosine substituted for the A76 nucleotide (2′dA-tRNA) and 1 μM M. mobile LeuRS. Amino acid-dependent AMP formation is measured by TLC of reaction aliquots from ATPase reactions with 5 mM isoleucine (A) or 5 mM leucine (B). Aminoacyl-adenylate was measured with 5 mM isoleucine (C) or 5 mM leucine (D). Fractions indicated by the y axis represent the intensity of the spot representing [32P]adenylate divided by the total intensity of 32P in the lane. Abbreviations are as follows: ■, isoleucine only (Ile); ▲, isoleucine and tRNA (Ile+tRNA); ▼, isoleucine and 2′dA-tRNA (Ile+2'dA); ◆, leucine only (Leu); ●, leucine and tRNA (Leu+tRNA); □, leucine and 2′dA-tRNA (Leu+2'dA); and ×, no amino acid control (No AA). Error bars represent SDs derived from triplicated reactions.