Architecture of the yeast small subunit processome.

Chaker-Margot M, Barandun J, Hunziker M, Klinge S

Science 355 (6321) - [2017-01-13; online 2016-12-15]

The small subunit (SSU) processome, a large ribonucleoprotein particle, organizes the assembly of the eukaryotic small ribosomal subunit by coordinating the folding, cleavage, and modification of nascent pre-ribosomal RNA (rRNA). Here, we present the cryo-electron microscopy structure of the yeast SSU processome at 5.1-angstrom resolution. The structure reveals how large ribosome biogenesis complexes assist the 5' external transcribed spacer and U3 small nucleolar RNA in providing an intertwined RNA-protein assembly platform for the separate maturation of 18S rRNA domains. The strategic placement of a molecular motor at the center of the particle further suggests a mechanism for mediating conformational changes within this giant particle. This study provides a structural framework for a mechanistic understanding of eukaryotic ribosome assembly in the model organism Saccharomyces cerevisiae.

Jonas Barandun

SciLifeLab Fellow

PubMed 27980088

DOI 10.1126/science.aal1880

Crossref 10.1126/science.aal1880

pii: science.aal1880

Publications 9.5.0