Structural roles of Ump1 and β-subunit propeptides in proteasome biogenesis.

ABSTRACT: The yeast pre1-1(β4-S142F) mutant accumulates late 20S proteasome core particle precursor complexes (late-PCs). We report a 2.1 Å cryo-EM structure of this intermediate with full-length Ump1 trapped inside, and Pba1-Pba2 attached to the α-ring surfaces. The structure discloses intimate interactions of Ump1 with β2- and β5-propeptides, which together fill most of the antechambers between the α- and β-rings. The β5-propeptide is unprocessed and separates Ump1 from β6 and β7. The β2-propeptide is disconnected from the subunit by autocatalytic processing and localizes between Ump1 and β3. A comparison of different proteasome maturation states reveals that maturation goes along with global conformational changes in the rings, initiated by structuring of the proteolytic sites and their au

SUBMITTER: Mark E 

PROVIDER: S-EPMC11391049 | biostudies-literature | 2024 Nov

REPOSITORIES: biostudies-literature