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Free keywords:
CRYO-EM STRUCTURE; 20S PROTEASOME; CRYOELECTRON TOMOGRAPHY; STRUCTURAL
INSIGHTS; CONFORMATIONAL LANDSCAPE; UBIQUITIN RECEPTORS; REVEALS
MECHANISMS; CRYSTAL-STRUCTURE; CHAIN-BINDING; REPEAT DOMAINBiochemistry & Molecular Biology; Biophysics; 26S proteasome; cryo-electron microscopy; cryo-electron tomography;
structural dynamics; AAA plus ATPases; single particle analysis;
Abstract:
In eukaryotic cells, the ubiquitin-proteasome system serves to remove proteins that are either dysfunctional or no longer needed. The 26S proteasome is a 2.5 MDa multisubunit complex comprising the 20S core particle, where degradation is executed, and one or two regulatory particles which prepare substrates for degradation. Whereas the 20S core particles of several species had been studied extensively by X-ray crystallography, the 26S holocomplex structure had remained elusive for a long time. Recent advances in single-particle cryo-electron microscopy have changed the situation and provided atomic resolution models of this intriguing molecular machine and its dynamics. Besides, cryo-electron tomography enables structural studies in situ, providing molecular resolution images of macromolecules inside pristinely preserved cellular environments. This has greatly contributed to our understanding of proteasome dynamics in the context of cells.
