The effect of tRNA structure and codon context on translation efficiency and fidelity

Microbiology Seminar Series

  • Date: Jun 17, 2024
  • Time: 01:15 PM (Local Time Germany)
  • Speaker: Prof. Kelly Hughes
  • University of Utah, School of Biological Sciences, USA
  • Location: MPI for Terrestrial Microbiology
  • Room: Lecture Hall / Hybrid
  • Host: Dr. Andreas Diepold
  • Contact:

The rate of translation of mRNA into protein is fine-tuned by factors including variations in translation-associated proteins, aminoacyl-tRNA concentrations, tRNA modifications and codon context. Translation rates can vary dramatically in a codon-pair orientation manner: the codon-pair UAC-UCA (Tyr- Ser) is translated fast, while the reverse orientation codon-pair UCA-UAC (Ser-Tyr) is translated slow. I will present a genetic selection developed in order to isolate mutants of the translation machinery that would increase the speed of translation through the slow translating codon pairs using the his operon leader peptide system. A single translation-fast mutant for the UCA-UAC pair was obtained in the D-stem of the essential tRNALeuZ. This mutation, A25G in the D-stem of tRNALeuZ, allowed for the recognition of the UCA serine codon and misincorporation of leucine by tRNALeuZ(A25G) at UCA serine codons. A model is presented where the mechanism of codon recognition ensures fidelity at the cost of translation speed.

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