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Structural analysis of the ribosome-associated complex (RAC) reveals an unusual Hsp70/Hsp40 interaction

Yeast Zuotin and Ssz are members of the conserved Hsp40 and Hsp70 chaperone families, respectively, but compared with canonical homologs, they atypically form a stable heterodimer termed ribosome-associated complex (RAC). RAC acts as co-chaperone for another Hsp70 to assist de novo protein folding....

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Main Authors: Fiaux Vogel, Jocelyne (Author) , Horst, Janina (Author) , Scior, Annika (Author) , Preißler, Steffen (Author) , Koplin, Ansgar (Author) , Bukau, Bernd (Author) , Deuerling, Elke (Author)
Format: Article (Journal)
Language:English
Published: 29 January 2010
In: The journal of biological chemistry
Year: 2010, Volume: 285, Issue: 5, Pages: 3227-3234
ISSN:1083-351X
DOI:10.1074/jbc.M109.075804
Online Access:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1074/jbc.M109.075804
Verlag, lizenzpflichtig, Volltext: https://www.sciencedirect.com/science/article/pii/S0021925820648177
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Author Notes:Jocelyne Fiaux, Janina Horst, Annika Scior, Steffen Preissler, Ansgar Koplin, Bernd Bukau, and Elke Deuerling
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Summary:Yeast Zuotin and Ssz are members of the conserved Hsp40 and Hsp70 chaperone families, respectively, but compared with canonical homologs, they atypically form a stable heterodimer termed ribosome-associated complex (RAC). RAC acts as co-chaperone for another Hsp70 to assist de novo protein folding. In this study, we identified the molecular basis for the unusual Hsp70/Hsp40 pairing using amide hydrogen exchange (HX) coupled with mass spectrometry and mutational analysis. Association of Ssz with Zuotin strongly decreased the conformational dynamics mainly in the C-terminal domain of Ssz, whereas Zuotin acquired strong conformational stabilization in its N-terminal segment. Deletion of the highly flexible N terminus of Zuotin abolished stable association with Ssz in vitro and caused a phenotype resembling the loss of Ssz function in vivo. Thus, the C-terminal domain of Ssz, the N-terminal extension of Zuotin, and their mutual stabilization are the major structural determinants for RAC assembly. We furthermore found dynamic changes in the J-domain of Zuotin upon complex formation that might be crucial for RAC co-chaperone function. Taken together, we present a novel mechanism for converting Zuotin and Ssz chaperones into a functionally active dimer.
Item Description:Online veröffentlicht am 17. November 2009
Gesehen am 23.10.2023
Physical Description:Online Resource
ISSN:1083-351X
DOI:10.1074/jbc.M109.075804

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