6XMJ

Human 20S proteasome bound to an engineered 11S (PA26) activator

Summary for 6XMJ

• Entry DOI: 10.2210/pdb6xmj/pdb
• EMDB information: 22259
• Descriptor: Proteasome subunit alpha type-6, Proteasome subunit beta type-3, Proteasome subunit beta type-2, ... (15 entities in total)
• Functional Keywords: 11s-bound, 20s proteasome, hydrolase
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 21
• Total formula weight: 523664.12

Authors

de la Pena, A.H.,Opoku-Nsiah, K.A.,Williams, S.K.,Chopra, N.,Sali, A.,Gestwicki, J.E.,Lander, G.C. (deposition date: 2020-06-30, release date: 2020-07-22, Last modification date: 2024-05-15)

Primary citation

Opoku-Nsiah, K.A.,de la Pena, A.H.,Williams, S.K.,Chopra, N.,Sali, A.,Lander, G.C.,Gestwicki, J.E.
The Y Phi motif defines the structure-activity relationships of human 20S proteasome activators.
Nat Commun, 13:1226-1226, 2022

PubMed Abstract: The 20S proteasome (20S) facilitates turnover of most eukaryotic proteins. Substrate entry into the 20S first requires opening of gating loops through binding of HbYX motifs that are present at the C-termini of certain proteasome activators (PAs). The HbYX motif has been predominantly characterized in the archaeal 20S, whereas little is known about the sequence preferences of the human 20S (h20S). Here, we synthesize and screen ~120 HbYX-like peptides, revealing unexpected differences from the archaeal system and defining the h20S recognition sequence as the Y-F/Y (YФ) motif. To gain further insight, we create a functional chimera of the optimized sequence, NLSYYT, fused to the model activator, PA26. A cryo-EM structure of PA26-h20S is used to identify key interactions, including non-canonical contacts and gate-opening mechanisms. Finally, we demonstrate that the YФ sequence preferences are tuned by valency, allowing multivalent PAs to sample greater sequence space. These results expand the model for termini-mediated gating and provide a template for the design of h20S activators.

PubMed: 35264557
DOI: 10.1038/s41467-022-28864-x

Experimental method

ELECTRON MICROSCOPY (3 Å)