Single Atomic Group in RNA Helix Needed for Positive and Negative tRNA Synthetase Discrimination

摘要

To maintain the fidelity of protein synthesis, 20 aminoacyl-tRNA synthetases must discriminate among the approximately 60 cellular tRNAs. Both positive recognition elements in the cognate systems and negative elements used for noncognate discrimination contribute to the so-called "identity set" of each tRNA. While positive recognition elements have now been identified for all 20 Escherichia coli synthetases, only a few negative or blocking elements have been elucidated to date. In this work, we identify a specific atomic group in the acceptor helix of a tRNA that contributes significantly to both positive recognition by the cognate synthetase and negative discrimination by a noncognate enzyme.