ATP binding to neighbouring subunits and intersubunit allosteric coupling underlie proteasomal ATPase function
| Autor: | David M. Smith, Youngchan Kim, Aaron Snoberger, Jane E. Schupp |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Proteasome Endopeptidase Complex
Protein subunit ATPase Allosteric regulation General Physics and Astronomy Biology Article General Biochemistry Genetics and Molecular Biology 03 medical and health sciences chemistry.chemical_compound Adenosine Triphosphate Allosteric Regulation Humans 030304 developmental biology Adenosine Triphosphatases 0303 health sciences Multidisciplinary Hydrolysis 030302 biochemistry & molecular biology ATPase complex General Chemistry Förster resonance energy transfer Proteasome chemistry Biochemistry Biophysics biology.protein Adenosine triphosphate Function (biology) |
| Zdroj: | Nature Communications |
| ISSN: | 2041-1723 |
| DOI: | 10.1038/ncomms9520 |
| Popis: | The primary functions of the proteasome are driven by a highly allosteric ATPase complex. ATP binding to only two subunits in this hexameric complex triggers substrate binding, ATPase–20S association and 20S gate opening. However, it is unclear how ATP binding and hydrolysis spatially and temporally coordinates these allosteric effects to drive substrate translocation into the 20S. Here, we use FRET to show that the proteasomal ATPases from eukaryotes (RPTs) and archaea (PAN) bind ATP with high affinity at neighbouring subunits, which complements the well-established spiral-staircase topology of the 26S ATPases. We further show that two conserved arginine fingers in PAN located at the subunit interface work together as a single allosteric unit to mediate the allosteric effects of ATP binding, without altering the nucleotide-binding pattern. Rapid kinetics analysis also shows that ring resetting of a sequential hydrolysis mechanism can be explained by thermodynamic equilibrium binding of ATP. These data support a model whereby these two functionally distinct allosteric networks cooperate to translocate polypeptides into the 20S for degradation. The 26S proteasome contains a hexamer of ATPase subunits, which binds, unfolds and translocates substrates in an ATP-dependent manner. Kim et al. use FRET to show that ATP binding preferentially occurs at neighbouring subunits of the hexamer, and identify two allosteric systems that coordinate translocation. |
| Databáze: | OpenAIRE |
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