1. Quality control of protein synthesis in the early elongation stage
- Author
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Asuteka Nagao, Yui Nakanishi, Yutaro Yamaguchi, Yoshifumi Mishina, Minami Karoji, Takafumi Toya, Tomoya Fujita, Shintaro Iwasaki, Kenjyo Miyauchi, Yuriko Sakaguchi, and Tsutomu Suzuki
- Subjects
Science - Abstract
Abstract In the early stage of bacterial translation, peptidyl-tRNAs frequently dissociate from the ribosome (pep-tRNA drop-off) and are recycled by peptidyl-tRNA hydrolase. Here, we establish a highly sensitive method for profiling of pep-tRNAs using mass spectrometry, and successfully detect a large number of nascent peptides from pep-tRNAs accumulated in Escherichia coli pth ts strain. Based on molecular mass analysis, we found about 20% of the peptides bear single amino-acid substitutions of the N-terminal sequences of E. coli ORFs. Detailed analysis of individual pep-tRNAs and reporter assay revealed that most of the substitutions take place at the C-terminal drop-off site and that the miscoded pep-tRNAs rarely participate in the next round of elongation but dissociate from the ribosome. These findings suggest that pep-tRNA drop-off is an active mechanism by which the ribosome rejects miscoded pep-tRNAs in the early elongation, thereby contributing to quality control of protein synthesis after peptide bond formation.
- Published
- 2023
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