Structural characterization of NrnC identifies unifying features of dinucleotidases
| Autor: | Lormand, Justin D., Kim, Soo-Kyoung, Walters-Marrah, George A., Brownfield, Bryce A., Christopher Fromme, J., Winkler, Wade C., Goodson, Jonathan R., Lee, Vincent T., Sondermann, Holger |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | eLife eLife 10, e70146 (2021). doi:10.7554/eLife.70146 |
| ISSN: | 2050-084X |
| DOI: | 10.7554/eLife.70146 |
| Popis: | eLife 10, e70146 (2021). doi:10.7554/eLife.70146 RNA degradation is fundamental for cellular homeostasis. The process is carried out by various classes of endolytic and exolytic enzymes that together degrade an RNA polymer to mono-ribonucleotides. Within the exoribonucleases, nano-RNases play a unique role as they act on the smallest breakdown products and hence catalyze the final steps in the process. We recently showed that oligoribonuclease (Orn) acts as a dedicated diribonucleotidase, defining the ultimate step in RNA degradation that is crucial for cellular fitness (Kim et al., 2019). Whether such a specific activity exists in organisms that lack Orn-type exoribonucleases remained unclear. Through quantitative structure-function analyses we show here that NrnC-type RNases share this narrow substrate preference with Orn. Although NrnC employs similar structural features that distinguish these two classes as diribonucleotidases from other exoribonucleases, these key determinants for diribonucleotidase activity are realized through distinct structural scaffolds. The structures together with comparative genomic analyses of the phylogeny of DEDD-type exoribonucleases indicates convergent evolution as the mechanism of how diribonucleotidase activity emerged repeatedly in various organisms. The evolutionary pressure to maintain diribonucleotidase activity further underlines the important role these analogous proteins play for cell growth. Published by eLife Sciences Publications, Cambridge |
| Databáze: | OpenAIRE |
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