Observing Protein Degradation by the PAN-20S Proteasome by Time-Resolved Neutron Scattering.
Biophys J
; 119(2): 375-388, 2020 07 21.
Article
en En
| MEDLINE
| ID: mdl-32640186
ABSTRACT
The proteasome is a key player of regulated protein degradation in all kingdoms of life. Although recent atomic structures have provided snapshots on a number of conformations, data on substrate states and populations during the active degradation process in solution remain scarce. Here, we use time-resolved small-angle neutron scattering of a deuterium-labeled GFPssrA substrate and an unlabeled archaeal PAN-20S system to obtain direct structural information on substrate states during ATP-driven unfolding and subsequent proteolysis in solution. We find that native GFPssrA structures are degraded in a biexponential process, which correlates strongly with ATP hydrolysis, the loss of fluorescence, and the buildup of small oligopeptide products. Our solution structural data support a model in which the substrate is directly translocated from PAN into the 20S proteolytic chamber, after a first, to our knowledge, successful unfolding process that represents a point of no return and thus prevents dissociation of the complex and the release of harmful, aggregation-prone products.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Adenosina Trifosfatasas
/
Complejo de la Endopetidasa Proteasomal
Idioma:
En
Revista:
Biophys J
Año:
2020
Tipo del documento:
Article
País de afiliación:
Francia