Enzymatic activities of wild-type GlLeuRS and its mutants in
the alanine scanning assay. A, the ATP-PPi exchange
reaction was carried out using 1 mm Leu and 20 nm
enzyme. B, the aminoacylation assay was carried out using 50
nm GlLeuRS or its mutants. C, post-transfer
editing was performed using 2 μm
[3H]Ile-tRNALeu from GltRNALeu and
20 nm GlLeuRS or its mutants. Symbols are
GlLeuRS (•), GlLeuRS-Y581A (○),
GlLeuRS-W586A (▾), GlLeuRS-K587A (▵),
GlLeuRS-D588A (▪), GlLeuRS-D603A (□),
GlLeuRS-K606A (♦), and GlLeuRS-F609A (⋄). Control
(spontaneous hydrolysis) (▴) was performed in the absence of enzyme.