Structural Features of the 26 S Proteasome Complex
| Autor: | Jürgen A. Kleinschmidt, Zdenka Cejka, Wolfgang Baumeister, Jan-Michael Peters, J. R. Harris |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Proteasome Endopeptidase Complex
medicine.medical_treatment Sequence (biology) Biology Xenopus laevis Multienzyme Complexes Structural Biology Salientia Image Processing Computer-Assisted medicine Animals Electrophoresis Gel Two-Dimensional Molecular Biology chemistry.chemical_classification Protease Antigen processing Proteasome complex biology.organism_classification Cell biology Cysteine Endopeptidases Microscopy Electron Enzyme chemistry Proteasome Biochemistry Digital image analysis Oocytes |
| Zdroj: | Journal of Molecular Biology. 234:932-937 |
| ISSN: | 0022-2836 |
| DOI: | 10.1006/jmbi.1993.1646 |
| Popis: | Proteasomes play a key role in the degradation of abnormal proteins, of short-lived regulatory proteins and in antigen processing. Evidence is accumulating that the 20 S proteasome represents the proteolytic core of the 26 S protease complex (26 S proteasome) which contains several additional subunits implicated in regulation and substrate recognition. Using electron microscopy and digital image analysis we obtained first insights into the structure of this complex which has an estimated molecular weight of approximately 2000 kDa. Two highly asymmetric masses which presumably contain the regulatory subunits of the 26 S complex are attached to both ends of the dimeric 20 S proteasome clearly reflecting its C2 symmetry. The structural uniformity of the complex, i.e. the absence of significant inter-image variations, has important implications for the structure of the latter: It indicates that, in spite of their sequence similarities, the various alpha-type and beta-type subunits of the 20 S proteasome are not promiscuous but occupy precisely defined positions. |
| Databáze: | OpenAIRE |
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