A Role for the Proteasome Alpha2 Subunit N-Tail in Substrate Processing.

ABSTRACT: The proteolytic active sites of the 26S proteasome are sequestered within the catalytic chamber of its 20S core particle (CP). Access to this chamber is through a narrow channel defined by the seven outer α subunits. In the resting state, the N-termini of neighboring α subunits form a gate blocking access to the channel. The attachment of the activators or regulatory particles rearranges the blocking α subunit N-termini facilitating the entry of substrates. By truncating or mutating each of the participating α N-termini, we report that whereas only a few N-termini are important for maintaining the closed gate, all seven N-termini participate in the open gate. Specifically, the open state is stabilized by a hydrogen bond between an invariant tyrosine (Y) in each subunit with a conserved asp

SUBMITTER: Sahu I 

PROVIDER: S-EPMC10046698 | biostudies-literature | 2023 Mar

REPOSITORIES: biostudies-literature