7Z3N

Cryo-EM structure of the ribosome-associated RAC complex on the 80S ribosome - RAC-1 conformation

This is a non-PDB format compatible entry.

Summary for 7Z3N

• Entry DOI: 10.2210/pdb7z3n/pdb
• EMDB information: 14479
• Descriptor: 26S rRNA, 60S ribosomal protein L3-like protein, 60S ribosomal protein L4-like protein, ... (88 entities in total)
• Functional Keywords: rac, ribosome-associated complex, thermophilic eukaryotic ribosome, 80s, chaperone
• Biological source: Thermochaetoides thermophila DSM 1495; More
• Total number of polymer chains: 86
• Total formula weight: 3361393.26

Authors

Kisonaite, M.,Wild, K.,Sinning, I. (deposition date: 2022-03-02, release date: 2023-04-12, Last modification date: 2023-05-31)

Primary citation

Kisonaite, M.,Wild, K.,Lapouge, K.,Gese, G.V.,Kellner, N.,Hurt, E.,Sinning, I.
Structural inventory of cotranslational protein folding by the eukaryotic RAC complex.
Nat.Struct.Mol.Biol., 30:670-677, 2023

PubMed Abstract: The challenge of nascent chain folding at the ribosome is met by the conserved ribosome-associated complex (RAC), which forms a chaperone triad with the Hsp70 protein Ssb in fungi, and consists of the non-canonical Hsp70 Ssz1 and the J domain protein Zuotin (Zuo1). Here we determine cryo-EM structures of Chaetomium thermophilum RAC bound to 80S ribosomes. RAC adopts two distinct conformations accommodating continuous ribosomal rotation by a flexible lever arm. It is held together by a tight interaction between the Ssz1 substrate-binding domain and the Zuo1 N terminus, and additional contacts between the Ssz1 nucleotide-binding domain and Zuo1 J- and Zuo1 homology domains, which form a rigid unit. The Zuo1 HPD motif conserved in J-proteins is masked in a non-canonical interaction by the Ssz1 nucleotide-binding domain, and allows the positioning of Ssb for activation by Zuo1. Overall, we provide the basis for understanding how RAC cooperates with Ssb in a dynamic nascent chain interaction and protein folding.

PubMed: 37081320
DOI: 10.1038/s41594-023-00973-1

Experimental method

ELECTRON MICROSCOPY (3.2 Å)