4JPO

5A resolution structure of Proteasome Assembly Chaperone Hsm3 in complex with a C-terminal fragment of Rpt1

Summary for 4JPO

• Entry DOI: 10.2210/pdb4jpo/pdb
• Descriptor: DNA mismatch repair protein HSM3, 26S protease regulatory subunit 7 homolog (2 entities in total)
• Functional Keywords: hsm3, chaperone, proteasome, protein complex, chaperone-hydrolase complex, chaperone/hydrolase
• Biological source: Saccharomyces cerevisiae (Baker's yeast); More
• Total number of polymer chains: 4
• Total formula weight: 136646.32

Authors

Lovell, S.,Battaile, K.P.,Singh, R.,Roelofs, J. (deposition date: 2013-03-19, release date: 2013-04-10, Last modification date: 2023-09-20)

Primary citation

Park, S.,Li, X.,Kim, H.M.,Singh, C.R.,Tian, G.,Hoyt, M.A.,Lovell, S.,Battaile, K.P.,Zolkiewski, M.,Coffino, P.,Roelofs, J.,Cheng, Y.,Finley, D.
Reconfiguration of the proteasome during chaperone-mediated assembly.
Nature, 497:512-516, 2013

PubMed Abstract: The proteasomal ATPase ring, comprising Rpt1-Rpt6, associates with the heptameric α-ring of the proteasome core particle (CP) in the mature proteasome, with the Rpt carboxy-terminal tails inserting into pockets of the α-ring. Rpt ring assembly is mediated by four chaperones, each binding a distinct Rpt subunit. Here we report that the base subassembly of the Saccharomyces cerevisiae proteasome, which includes the Rpt ring, forms a high-affinity complex with the CP. This complex is subject to active dissociation by the chaperones Hsm3, Nas6 and Rpn14. Chaperone-mediated dissociation was abrogated by a non-hydrolysable ATP analogue, indicating that chaperone action is coupled to nucleotide hydrolysis by the Rpt ring. Unexpectedly, synthetic Rpt tail peptides bound α-pockets with poor specificity, except for Rpt6, which uniquely bound the α2/α3-pocket. Although the Rpt6 tail is not visualized within an α-pocket in mature proteasomes, it inserts into the α2/α3-pocket in the base-CP complex and is important for complex formation. Thus, the Rpt-CP interface is reconfigured when the lid complex joins the nascent proteasome to form the mature holoenzyme.

PubMed: 23644457
DOI: 10.1038/nature12123

Experimental method

X-RAY DIFFRACTION (5 Å)