3h43

Publication Abstract from PubMed

Eukaryotic proteasome consists of a core particle (CP), which degrades unfolded protein, and a regulatory particle (RP), which is responsible for recognition, ATP-dependent unfolding, and translocation of polyubiquitinated substrate protein. In the archaea Methanocaldococcus jannaschii, the RP is a homohexameric complex of proteasome-activating nucleotidase (PAN). Here, we report the crystal structures of essential elements of the archaeal proteasome: the CP, the ATPase domain of PAN, and a distal subcomplex that is likely the first to encounter substrate. The distal subcomplex contains a coiled-coil segment and an OB-fold domain, both of which appear to be conserved in the eukaryotic proteasome. The OB domains of PAN form a hexameric ring with a 13 A pore, which likely constitutes the outermost constriction of the substrate translocation channel. These studies reveal structural codes and architecture of the complete proteasome, identify potential substrate-binding sites, and uncover unexpected asymmetry in the RP of archaea and eukaryotes.

Structural insights into the regulatory particle of the proteasome from Methanocaldococcus jannaschii.,Zhang F, Hu M, Tian G, Zhang P, Finley D, Jeffrey PD, Shi Y Mol Cell. 2009 May 14;34(4):473-84. PMID:19481527^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.