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-Structure paper
Title | Structural inventory of cotranslational protein folding by the eukaryotic RAC complex. |
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Journal, issue, pages | Nat Struct Mol Biol, Vol. 30, Issue 5, Page 670-677, Year 2023 |
Publish date | Apr 20, 2023 |
Authors | Miglė Kišonaitė / Klemens Wild / Karine Lapouge / Genís Valentín Gesé / Nikola Kellner / Ed Hurt / Irmgard Sinning / |
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 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. |
External links | Nat Struct Mol Biol / PubMed:37081320 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.2 - 3.3 Å |
Structure data | EMDB-14479, PDB-7z3n: EMDB-14480, PDB-7z3o: |
Chemicals | ChemComp-MG: ChemComp-ATP: ChemComp-ZN: |
Source |
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Keywords | CHAPERONE / RAC / ribosome-associated complex / thermophilic eukaryotic ribosome / 80S |