Amino acid editing activities of LeuRS wild type and β-strand linker two-amino acid deletion mutants. The reactions containing approximately 4 µM [3H]-Ile-tRNALeu were initiated with 100 nM wild type or mutant LeuRS. A. N-terminal β-strand deletion mutant activities. B. C-terminal β-strand deletion mutant activities. Symbols are represented as follows: wild type (■), ΔS227E228 (▲), ΔG229V230 (▼), ΔE231I232 (◆), ΔT233F234 (●), ΔG407V408 (□), ΔG409E410(△), ΔR411K412 (▽), ΔV413N414 (◊) and no enzyme (X). Error bars are based on reactions that were repeated at least in triplicate.