7E55
Cryo-EM structure of alpha 7 homo-tetradecamer
Summary for 7E55
| Entry DOI | 10.2210/pdb7e55/pdb |
| EMDB information | 30990 |
| Descriptor | Proteasome subunit alpha type-3 (1 entity in total) |
| Functional Keywords | conformational fluctuation, double-ring, proteasome, d7 symmetry, chaperone, lyase |
| Biological source | Homo sapiens (Human) |
| Total number of polymer chains | 1 |
| Total formula weight | 28469.25 |
| Authors | Song, C.,Murata, K. (deposition date: 2021-02-17, release date: 2021-05-05, Last modification date: 2024-10-30) |
| Primary citation | Song, C.,Satoh, T.,Sekiguchi, T.,Kato, K.,Murata, K. Structural Fluctuations of the Human Proteasome alpha 7 Homo-Tetradecamer Double Ring Imply the Proteasomal alpha-Ring Assembly Mechanism. Int J Mol Sci, 22:-, 2021 Cited by PubMed Abstract: The 20S proteasome, which is composed of layered α and β heptameric rings, is the core complex of the eukaryotic proteasome involved in proteolysis. The α7 subunit is a component of the α ring, and it self-assembles into a homo-tetradecamer consisting of two layers of α7 heptameric rings. However, the structure of the α7 double ring in solution has not been fully elucidated. We applied cryo-electron microscopy to delineate the structure of the α7 double ring in solution, revealing a structure different from the previously reported crystallographic model. The D7-symmetrical double ring was stacked with a 15° clockwise twist and a separation of 3 Å between the two rings. Two more conformations, dislocated and fully open, were also identified. Our observations suggest that the α7 double-ring structure fluctuates considerably in solution, allowing for the insertion of homologous α subunits, finally converting to the hetero-heptameric α rings in the 20S proteasome. PubMed: 33926037DOI: 10.3390/ijms22094519 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (5.9 Å) |
Structure validation
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