Figure 1.

Aminoacyl-tRNA and Cys-AMP formation by G. lamblia ProCysRS. Aminoacylation was performed as described in Materials and Methods with 20 μM [³H]proline (A, ●) or 20 μM [³⁵S]cysteine (B, ▵). No activity was observed in the absence of either enzyme or tRNA (■). (C) Cys-AMP synthesis as measured in the ATP-PP_i exchange reaction. The assay conditions are described in Materials and Methods. Cys-AMP was measured in the presence of 1 mg/ml of (▴) or the absence of (▾) total M. jannaschii tRNA. ○, The background level (absence of enzyme from the reaction mixture).