SNAP annotations: PDB entry 7btb

PDB-id

7btb; DSSR-derived features in text and JSON formats; DNAproDB

Class

ribosome

Method

cryo-EM (3.22 Å)

Summary

cryo-EM structure of pre-60s ribosome from saccharomyces cerevisiae rpl4delta63-87 strain at 3.22 angstroms resolution(state r2)

Reference

Wilson DM, Li Y, LaPeruta A, Gamalinda M, Gao N, Woolford Jr JL (2020): "Structural insights into assembly of the ribosomal nascent polypeptide exit tunnel." Nat Commun, 11, 5111. doi: 10.1038/s41467-020-18878-8.

Abstract

The nascent polypeptide exit tunnel (NPET) is a major functional center of 60S ribosomal subunits. However, little is known about how the NPET is constructed during ribosome assembly. We utilized molecular genetics, biochemistry, and cryo-electron microscopy (cryo-EM) to investigate the functions of two NPET-associated proteins, ribosomal protein uL4 and assembly factor Nog1, in NPET assembly. Structures of mutant pre-ribosomes lacking the tunnel domain of uL4 reveal a misassembled NPET, including an aberrantly flexible ribosomal RNA helix 74, resulting in at least three different blocks in 60S assembly. Structures of pre-ribosomes lacking the C-terminal extension of Nog1 demonstrate that this extension scaffolds the tunnel domain of uL4 in the NPET to help maintain stability in the core of pre-60S subunits. Our data reveal that uL4 and Nog1 work together in the maturation of ribosomal RNA helix 74, which is required to ensure proper construction of the NPET and 60S ribosomal subunits.