2NBW

Solution structure of the Rpn1 T1 site with the Rad23 UBL domain

Summary for 2NBW

• Entry DOI: 10.2210/pdb2nbw/pdb
• Related: 2NBU 2NBV
• NMR Information: BMRB: 25825
• Descriptor: 26S proteasome regulatory subunit RPN1, UV excision repair protein RAD23 (2 entities in total)
• Functional Keywords: protein binding
• Biological source: Saccharomyces cerevisiae S288c (Baker's yeast); More
• Cellular location: Nucleus : P32628
• Total number of polymer chains: 2
• Total formula weight: 22347.69

Authors

Chen, X.,Walters, K.J. (deposition date: 2016-03-14, release date: 2016-07-20, Last modification date: 2024-05-01)

Primary citation

Chen, X.,Randles, L.,Shi, K.,Tarasov, S.G.,Aihara, H.,Walters, K.J.
Structures of Rpn1 T1:Rad23 and hRpn13:hPLIC2 Reveal Distinct Binding Mechanisms between Substrate Receptors and Shuttle Factors of the Proteasome.
Structure, 24:1257-1270, 2016

PubMed Abstract: Three receptors (Rpn1/S2/PSMD2, Rpn10/S5a, Rpn13/Adrm1) in the proteasome bind substrates by interacting with conjugated ubiquitin chains and/or shuttle factors (Rad23/HR23, Dsk2/PLIC/ubiquilin, Ddi1) that carry ubiquitinated substrates to proteasomes. We solved the structure of two such receptors with their preferred shuttle factor, namely hRpn13(Pru):hPLIC2(UBL) and scRpn1 T1:scRad23(UBL). We find that ubiquitin folds in Rad23 and Dsk2 are fine-tuned by residue substitutions to achieve high affinity for Rpn1 and Rpn13, respectively. A single substitution in hPLIC2 yields enhanced interactions with the Rpn13 ubiquitin contact surface and sterically blocks hRpn13 binding to its preferred ubiquitin chain type, K48-linked chains. Rpn1 T1 binds two ubiquitins in tandem and we find that Rad23 binds exclusively to the higher-affinity Helix28/Helix30 site. Rad23 contacts at Helix28/Helix30 are optimized compared to ubiquitin by multiple conservative amino acid substitutions. Thus, shuttle factors deliver substrates to proteasomes through fine-tuned ubiquitin-like surfaces.

PubMed: 27396824
DOI: 10.1016/j.str.2016.05.018

Experimental method

SOLUTION NMR