DISCRETE DETERMINANTS IN TRANSFER-RNA FOR EDITING AND AMINOACYLATION

During translation errors of aminoacylation are corrected in editing r eactions which ensure that an amino acid is stably attached to its cor responding transfer RNA (tRNA). Previous studies have not shown whethe r the tRNA nucleotides needed for effecting translational editing are the same as or distinct from those required for aminoacylation, but se veral considerations have suggested that they are the same. Here, desi gned tRNAs that are highly active for aminoacylation but are not activ e in translational editing are presented. The editing reaction can be controlled by manipulation of nucleotides at the corner of the L-shape d tRNA. In contrast, these manipulations do not affect aminoacylation. These results demonstrate the segregation of nucleotide determinants for the editing and aminoacylation functions of tRNA.