Seminar by Yonatan Chemla – University of Copenhagen

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Seminar by Yonatan Chemla

Title: Evidence for efficient termination of translation in bacteria being a two condition ‘AND’ gate
Yonatan Chemla, PhD student
Department of life sciences, Ben-Gurion University, Israel
Ribosomal protein synthesis is terminated upon stop codon recognition by release factors. How release factors recognize and react with stop codons was generally thought to be a process of molecular sampling of the mRNA where the only condition to be fulfilled is the presence of in-frame stop codon. However, preliminary experiments (in addition to past observations which were largely overlooked) cannot be reconciled under the existing paradigm and therefore it might need to be expanded and articulated. These preliminary experiments illustrate that translation termination mechanism obeys a fussy logic ‘AND’ gate where two conditions need to be fulfilled: presence of in-frame stop codon and additional stable mRNA element such as transcription terminators and ribosome binding domains which are correlated to 3’ UTR proximity. In addition to its fit to experimentation this mechanism makes evolutionary sense as it provides bacteria with a mechanism to detect incorrect stop signals and sequentially degrade the abnormal protein thereby avoiding truncated protein misfolding and aggregation.