Details

Autor(en) / Beteiligte

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

Titel

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

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 2012-09, Vol.109 (37), p.14870-14875

Ort / Verlag

United States: National Academy of Sciences

Erscheinungsjahr

2012

Quelle

MEDLINE

Beschreibungen/Notizen

• The 26S proteasome operates at the executive end of the ubiquitinproteasome 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.