6ZQC

Cryo-EM structure of the 90S pre-ribosome from Saccharomyces cerevisiae, state Pre-A1

This is a non-PDB format compatible entry.

Summary for 6ZQC

• Entry DOI: 10.2210/pdb6zqc/pdb
• EMDB information: 11359
• Descriptor: rRNA 2'-O-methyltransferase fibrillarin, U3 small nucleolar RNA-associated protein 7, U3 small nucleolar RNA-associated protein 8, ... (70 entities in total)
• Functional Keywords: ribosome, 90s pre-ribosome, 40s pre-ribosome, a1 cleavage, dhr1
• Biological source: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast); More
• Total number of polymer chains: 71
• Total formula weight: 4866244.50

Authors

Cheng, J.,Lau, B.,Venuta, G.L.,Berninghausen, O.,Hurt, E.,Beckmann, R. (deposition date: 2020-07-09, release date: 2020-09-23, Last modification date: 2024-05-01)

Primary citation

Cheng, J.,Lau, B.,La Venuta, G.,Ameismeier, M.,Berninghausen, O.,Hurt, E.,Beckmann, R.
90 S pre-ribosome transformation into the primordial 40 S subunit.
Science, 369:1470-1476, 2020

PubMed Abstract: Production of small ribosomal subunits initially requires the formation of a 90 precursor followed by an enigmatic process of restructuring into the primordial pre-40 subunit. We elucidate this process by biochemical and cryo-electron microscopy analysis of intermediates along this pathway in yeast. First, the remodeling RNA helicase Dhr1 engages the 90 pre-ribosome, followed by Utp24 endonuclease-driven RNA cleavage at site A, thereby separating the 5'-external transcribed spacer (ETS) from 18 ribosomal RNA. Next, the 5'-ETS and 90 assembly factors become dislodged, but this occurs sequentially, not en bloc. Eventually, the primordial pre-40 emerges, still retaining some 90 factors including Dhr1, now ready to unwind the final small nucleolar U3-18 RNA hybrid. Our data shed light on the elusive 90 to pre-40 transition and clarify the principles of assembly and remodeling of large ribonucleoproteins.

PubMed: 32943521
DOI: 10.1126/science.abb4119

Experimental method

ELECTRON MICROSCOPY (3.8 Å)