Cryo-EM reveals active site coordination within a multienzyme pre-rRNA processing complex.

Journal Article (Journal Article)

Ribosome assembly is a complex process reliant on the coordination of trans-acting enzymes to produce functional ribosomal subunits and secure the translational capacity of cells. The endoribonuclease (RNase) Las1 and the polynucleotide kinase (PNK) Grc3 assemble into a multienzyme complex, herein designated RNase PNK, to orchestrate processing of precursor ribosomal RNA (rRNA). RNase PNK belongs to the functionally diverse HEPN nuclease superfamily, whose members rely on distinct cues for nuclease activation. To establish how RNase PNK coordinates its dual enzymatic activities, we solved a series of cryo-EM structures of Chaetomium thermophilum RNase PNK in multiple conformational states. The structures reveal that RNase PNK adopts a butterfly-like architecture, harboring a composite HEPN nuclease active site flanked by discrete RNA kinase sites. We identify two molecular switches that coordinate nuclease and kinase function. Together, our structures and corresponding functional studies establish a new mechanism of HEPN nuclease activation essential for ribosome production.

Full Text

Duke Authors

Cited Authors

  • Pillon, MC; Hsu, AL; Krahn, JM; Williams, JG; Goslen, KH; Sobhany, M; Borgnia, MJ; Stanley, RE

Published Date

  • September 2019

Published In

Volume / Issue

  • 26 / 9

Start / End Page

  • 830 - 839

PubMed ID

  • 31488907

Pubmed Central ID

  • PMC6733591

Electronic International Standard Serial Number (EISSN)

  • 1545-9985

Digital Object Identifier (DOI)

  • 10.1038/s41594-019-0289-8


  • eng

Conference Location

  • United States