FIGURE 4.

Gel mobility-shift assays for the tRNA binding activities of the Ad and Wt and mutant yeast ValRSs. Affinities of the Ad and Wt and mutant ValRSs toward ³²P-labeled unfractionated yeast tRNA or in vitro-transcribed yeast tRNA^Val were determined by polyacrylamide gel coelectrophoresis. At the bottom of each gel are the concentrations of the protein used. As a control, the left-most lane in each gel contained no protein. A, Ad binding unfractionated yeast tRNA. B, Ad binding yeast tRNA^Val. C, Wt binding unfractionated yeast tRNA; D, Wt binding yeast tRNA^Val. E, Δ1–97 binding yeast tRNA^Val; F, Δ32–71 binding yeast tRNA^Val.