6ef3
Yeast 26S proteasome bound to ubiquitinated substrate (4D motor state)Yeast 26S proteasome bound to ubiquitinated substrate (4D motor state)
Structural highlights
FunctionPSB1_YEAST The proteasome degrades poly-ubiquitinated proteins in the cytoplasm and in the nucleus. It is essential for the regulated turnover of proteins and for the removal of misfolded proteins. The proteasome is a multicatalytic proteinase complex that is characterized by its ability to cleave peptides with Arg, Phe, Tyr, Leu, and Glu adjacent to the leaving group at neutral or slightly basic pH. It has an ATP-dependent proteolytic activity. PRE3 and PRE4 are necessary for the peptidyl-glutamyl-peptide-hydrolyzing activity. This subunit is necessary for the peptidylglutamyl-peptide hydrolyzing activity. Publication Abstract from PubMedThe 26S proteasome is the primary eukaryotic degradation machine and thus critically involved in numerous cellular processes. The hetero-hexameric ATPase motor of the proteasome unfolds and translocates targeted protein substrates into the open gate of a proteolytic core, while a proteasomal deubiquitinase concomitantly removes substrate-attached ubiquitin chains. However, the mechanisms by which ATP hydrolysis drives the conformational changes responsible for these processes have remained elusive. Here we present the cryo-EM structures of four distinct conformational states of the actively ATP-hydrolyzing, substrate-engaged 26S proteasome. These structures reveal how mechanical substrate translocation accelerates deubiquitination, and how ATP-binding, hydrolysis, and phosphate-release events are coordinated within the AAA+ motor to induce conformational changes and propel the substrate through the central pore. Substrate-engaged 26S proteasome structures reveal mechanisms for ATP-hydrolysis-driven translocation.,de la Pena AH, Goodall EA, Gates SN, Lander GC, Martin A Science. 2018 Oct 11. pii: science.aav0725. doi: 10.1126/science.aav0725. PMID:30309908[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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