Near-atomic resolution structural model of the yeast 26S proteasome

Florian Beck, Pia Unverdorben, Stefan Bohn, Andreas Schweitzer, Günter Pfeifer, Eri Sakata, Stephan Nickell, Jürgen M Plitzko, Elizabeth Villa, Wolfgang Baumeister, Friedrich Förster

Research output: Contribution to journalArticleAcademicpeer-review


The 26S proteasome operates at the executive end of the ubiquitin-proteasome pathway. Here, we present a cryo-EM structure of the Saccharomyces cerevisiae 26S proteasome at a resolution of 7.4 Å or 6.7 Å (Fourier-Shell Correlation of 0.5 or 0.3, respectively). We used this map in conjunction with molecular dynamics-based flexible fitting to build a near-atomic resolution model of the holocomplex. The quality of the map allowed us to assign α-helices, the predominant secondary structure element of the regulatory particle subunits, throughout the entire map. We were able to determine the architecture of the Rpn8/Rpn11 heterodimer, which had hitherto remained elusive. The MPN domain of Rpn11 is positioned directly above the AAA-ATPase N-ring suggesting that Rpn11 deubiquitylates substrates immediately following commitment and prior to their unfolding by the AAA-ATPase module. The MPN domain of Rpn11 dimerizes with that of Rpn8 and the C-termini of both subunits form long helices, which are integral parts of a coiled-coil module. Together with the C-terminal helices of the six PCI-domain subunits they form a very large coiled-coil bundle, which appears to serve as a flexible anchoring device for all the lid subunits.

Original languageEnglish
Pages (from-to)14870-5
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number37
Publication statusPublished - 11 Sept 2012
Externally publishedYes


  • Cryoelectron Microscopy
  • Endopeptidases
  • Models, Molecular
  • Molecular Dynamics Simulation
  • Proteasome Endopeptidase Complex
  • Protein Structure, Tertiary
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins


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