4B4T: Near-atomic Resolution Structural Model of the Yeast 26S Proteasome

Citation:
Abstract
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 A or 6.7 A (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 alpha-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.
PDB ID: 4B4TDownload
MMDB ID: 102701
PDB Deposition Date: 2012/8/1
Updated in MMDB: 2013/09 
Experimental Method:
electron microscopy
Resolution: 7.4  Å
Source Organism:

*This MMDB ID is obsolete.

Molecular Components in 4B4T
Label Count Molecule
Proteins (31 molecules)
1
Proteasome Component Pre3
Molecule annotation
1
Proteasome Component Pup1
Molecule annotation
1
Proteasome Component Pup3
Molecule annotation
1
Proteasome Component C11
Molecule annotation
1
Proteasome Component Pre2
Molecule annotation
1
Proteasome Component C5
Molecule annotation
1
Proteasome Component Pre4
Molecule annotation
1
Proteasome Component C7-alpha
Molecule annotation
1
Proteasome Component Y7
Molecule annotation
1
Proteasome Component Y13
Molecule annotation
1
Proteasome Component Pre6
Molecule annotation
1
Proteasome Component Pup2
Molecule annotation
1
Proteasome Component Pre5
Molecule annotation
1
Proteasome Component C1
Molecule annotation
1
26S Protease Regulatory Subunit 7 Homolog
Molecule annotation
1
26S Protease Regulatory Subunit 4 Homolog
Molecule annotation
1
26S Protease Regulatory Subunit 8 Homolog
Molecule annotation
1
26S Protease Regulatory Subunit 6B Homolog
Molecule annotation
1
26S Protease Subunit Rpt4
Molecule annotation
1
26S Protease Regulatory Subunit 6A
Molecule annotation
1
26S Proteasome Regulatory Subunit Rpn2
Molecule annotation
1
26S Proteasome Regulatory Subunit Rpn9
Molecule annotation
1
26S Proteasome Regulatory Subunit Rpn5
Molecule annotation
1
26S Proteasome Regulatory Subunit Rpn6
Molecule annotation
1
26S Proteasome Regulatory Subunit Rpn7
Molecule annotation
1
26S Proteasome Regulatory Subunit Rpn3
Molecule annotation
1
26S Proteasome Regulatory Subunit Rpn12
Molecule annotation
1
26S Proteasome Regulatory Subunit Rpn8
Molecule annotation
1
26S Proteasome Regulatory Subunit Rpn11
Molecule annotation
1
26S Proteasome Regulatory Subunit Rpn10
Molecule annotation
1
26S Proteasome Regulatory Subunit Rpn13
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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