STRUCTURE AND STRUCTURE FORMATION OF THE 20S PROTEASOME

摘要: Eukaryotic 20S proteasomes are complex oligomeric proteins. The maturation process of the 14 different α- and β-subunits has to occur in a highly coordinate manner. In addition synthesized as proproteins correct processing be guaranteed during maturation. structure formation can subdivided phases. knowledge individual phases is summarized this publication. As first step newly monomers have adopt tertiary structure, that might supported case by intramolecular chaperone activity postulated for prosequences. Subsequently α-subunits form ring-like structures thereby providing docking sites β-subunits. result most likely double ring (13S precursor) representing half-proteasomes, which contain immature proproteins. Two 13S precursors associate proteolytically inactive 16S assembly intermediate still contains unprocessed β-monomers. Hsc73 present within these particles suggesting an essential role process. with N-terminal threonine occurs achieved autocatalytically two subsequent events finally leading mature, active proteasome.