Structural models for interactions between the 20S proteasome and its PAN/19S activators.

ABSTRACT: Proteasome activity is regulated by sequestration of its proteolytic centers in a barrel-shaped structure that limits substrate access. Substrates enter the proteasome by means of activator complexes that bind to the end rings of proteasome alpha subunits and induce opening of an axial entrance/exit pore. The PA26 activator binds in a pocket on the proteasome surface using main chain contacts of its C-terminal residues and uses an internal activation loop to trigger gate opening by repositioning the proteasome Pro-17 reverse turn. Subunits of the unrelated PAN/19S activators bind with their C termini in the same pockets but can induce proteasome gate opening entirely from interactions of their C-terminal peptides, which are reported to cause gate opening by inducing a rocking motion of pro

SUBMITTER: Stadtmueller BM 

PROVIDER: S-EPMC2804157 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature