Efficient aminoacylation of a yeast tRNAAsp transcript with a 5' extension

Abstract

A yeast aspartic acid tRNA with a 5' extension of 14 nucleotides was obtained by in vitro transcription with T7 DNA dependent RNA polymerase. This transcript, called extended tRNA^Asp transcript, retains its aspartylation capacity with the same K _m and only three times reduced k _cal values as compared to those measured for canonical tRNA^Asp. This result indicates that the 5' extension of the amino acid acceptor stem of tRNA^Asp does not interfere with recognition by aspartyl‐tRNA synthetase. However, in contrast to the wild‐type tRNA^Asp transcript, the 5' extended molecule presents a reduced capacity to be mischarged by arginyl‐tRNA synthetase, suggesting the existence of different structural requirements in aspartyland arginyl‐tRNA synthetases for tRNA^Asp recognition.