7MQA

Cryo-EM structure of the human SSU processome, state post-A1

This is a non-PDB format compatible entry.

Summary for 7MQA

• Entry DOI: 10.2210/pdb7mqa/pdb
• EMDB information: 23936 23937 23938 23939 23940 24163 24165 24166 24168 24169 24170 24171 24172 24173 24175
• Descriptor: 5'ETS rRNA, 40S ribosomal protein S9, 40S ribosomal protein S12, ... (73 entities in total)
• Functional Keywords: ribosomal assembly intermediate, ribosome
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 72
• Total formula weight: 5578683.28

Authors

Vanden Broeck, A.,Singh, S.,Klinge, S. (deposition date: 2021-05-05, release date: 2021-09-22, Last modification date: 2024-10-30)

Primary citation

Singh, S.,Vanden Broeck, A.,Miller, L.,Chaker-Margot, M.,Klinge, S.
Nucleolar maturation of the human small subunit processome.
Science, 373:eabj5338-eabj5338, 2021

PubMed Abstract: The human small subunit processome mediates early maturation of the small ribosomal subunit by coupling RNA folding to subsequent RNA cleavage and processing steps. We report the high-resolution cryo–electron microscopy structures of maturing human small subunit (SSU) processomes at resolutions of 2.7 to 3.9 angstroms. These structures reveal the molecular mechanisms that enable crucial progressions during SSU processome maturation. RNA folding states within these particles are communicated to and coordinated with key enzymes that drive irreversible steps such as targeted exosome-mediated RNA degradation, protein-guided site-specific endonucleolytic RNA cleavage, and tightly controlled RNA unwinding. These conserved mechanisms highlight the SSU processome’s impressive structural plasticity, which endows this 4.5-megadalton nucleolar assembly with the distinctive ability to mature the small ribosomal subunit from within.

PubMed: 34516797
DOI: 10.1126/science.abj5338

Experimental method

ELECTRON MICROSCOPY (2.7 Å)