| Autor: |
Sonja Bonin, Claude Sauter, Mario Mörl, O. Hennig, Susanne Philipp, Tim Kolberg, K. Rollet, Heike Betat, Tina Jühling |
| Rok vydání: |
2020 |
| Předmět: |
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| DOI: |
10.1101/2020.07.07.190959 |
| Popis: |
The mitochondrial genome of the nematodeRomanomermis culicivoraxencodes for miniaturized hairpin-like tRNA molecules that lack D- as well as T-arms, strongly deviating from the consensus cloverleaf. The single tRNA nucleotidyltransferase of this organism is fully active on armless tRNAs, while the human counterpart is not able to add a complete CCA-end. Transplanting single regions of theRomanomermisenzyme into the human counterpart, we identified a beta-turn element of the catalytic core that – when inserted into the human enzyme - confers full CCA-adding activity on armless tRNAs. This region, originally identified to position the 3’-end of the tRNA primer in the catalytic core, dramatically increases the enzyme’s substrate affinity. While conventional tRNA substrates bind to the enzyme by interactions with the T-arm, this is not possible in the case of armless tRNAs, and the strong contribution of the beta-turn compensates for an otherwise too weak interaction required for the addition of a complete CCA-terminus. This compensation demonstrates the remarkable evolutionary plasticity of the catalytic core elements of this enzyme to adapt to unconventional tRNA substrates. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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