Structures of B. subtilis Maturation RNases Captured on 50S Ribosome with Pre-rRNAs.

Stephanie Oerum, Tom Dendooven, Marjorie Catala, Laetitia Gilet, Clément Dégut, Aude Trinquier, Maxime Bourguet, Pierre Barraud, Sarah Cianferani, Ben F Luisi, Ciarán Condon, Carine Tisné

Molecular cell 2020 Oct 15

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The pathways for ribosomal RNA (rRNA) maturation diverge greatly among the domains of life. In the Gram-positive model bacterium, Bacillus subtilis, the final maturation steps of the two large ribosomal subunit (50S) rRNAs, 23S and 5S pre-rRNAs, are catalyzed by the double-strand specific ribonucleases (RNases) Mini-RNase III and RNase M5, respectively. Here we present a protocol that allowed us to solve the 3.0 and 3.1 Å resolution cryoelectron microscopy structures of these RNases poised to cleave their pre-rRNA substrates within the B. subtilis 50S particle. These data provide the first structural insights into rRNA maturation in bacteria by revealing how these RNases recognize and process double-stranded pre-rRNA. Our structures further uncover how specific ribosomal proteins act as chaperones to correctly fold the pre-rRNA substrates and, for Mini-III, anchor the RNase to the ribosome. These r-proteins thereby serve a quality-control function in the process from accurate ribosome assembly to rRNA processing. Copyright © 2020 Elsevier Inc. All rights reserved.

Citation

Stephanie Oerum, Tom Dendooven, Marjorie Catala, Laetitia Gilet, Clément Dégut, Aude Trinquier, Maxime Bourguet, Pierre Barraud, Sarah Cianferani, Ben F Luisi, Ciarán Condon, Carine Tisné. Structures of B. subtilis Maturation RNases Captured on 50S Ribosome with Pre-rRNAs. Molecular cell. 2020 Oct 15;80(2):227-236.e5