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Article Dans Une Revue Biophysical Journal Année : 2020

Observing protein degradation by the PAN-20S proteasome by time-resolved neutron scattering

Résumé

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.
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hal-03456352 , version 1 (22-08-2022)

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Paternité - Pas d'utilisation commerciale - Pas de modification

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Emilie Mahieu, Jacques Covès, Georg Krüger, Anne Martel, Martine Moulin, et al.. Observing protein degradation by the PAN-20S proteasome by time-resolved neutron scattering. Biophysical Journal, 2020, 119 (2), pp.375-388. ⟨10.1016/j.bpj.2020.06.015⟩. ⟨hal-03456352⟩
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