Transcription-translation coupling at the stages of translation initiation and elongation
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| Year of publication | 2021 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | In Bacteria and Archaea, mRNAs are translated by ribosomes simultaneously as they are transcribed. Visualization of actively transcribing RNA polymerase (RNAP) in E.coli by electron microscopy provided clear insight into physically coupled transcription and translation (CTT) mechanism. Additionally, some biochemical studies confirmed the synchronous rates of transcription and translation in E.coli suggesting a regulation function of the leading ribosome on the RNAP propagation which is crucial for optimal gene expression and genome stability. Here, we present cryo-electron microscopy (cryo-EM) structure of E. coli RNAP core bound to the small ribosomal 30S subunit. Alignment of the RNA exit tunnel of RNAP with the Shine-Dalgarno (SD) binding site of 30S subunit suggests a possible loading mechanism of the mRNA onto the 30S subunit at the stage of translation initiation. The recent expressome structures showed RNAP near the mRNA entry tunnel of the trailing ribosome. This region is more than 80 A away from the binding site observed in 30S-RNAP structure, suggesting a large-scale relocation of RNAP. The 30S-RNAP and expressome structures may therefore represent interactions that occur at different steps of translation, especially during initiation and elongation. Future studies are aimed at investigating the initiation and elongation steps of CTT using time-resolved cryo-EM approach. |
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