Structures of the ATP-fueled ClpXP proteolytic machine bound to protein substrate
Name
elife-52774-v2.pdf
Description
Published version
Size
4.57 MB
Format
Unknown
Checksum (MD5)
91d22f16abbb78f1f7dbdfdfde0b6a58
Author(s)
Fei, Xue
Bell, Tristan Andrew
Jenni, Simon
Stinson, Benjamin Michael
Baker, Tania
Harrison, Stephen C
Sauer, Robert T
Date Issued
2020
Journal
eLife
Publisher
eLife Sciences Publications, Ltd
Version
Final published version
Abstract
© 2020, eLife Sciences Publications Ltd. All rights reserved. ClpXP is an ATP-dependent protease in which the ClpX AAA+ motor binds, unfolds, and translocates specific protein substrates into the degradation chamber of ClpP. We present cryo-EM studies of the E. coli enzyme that show how asymmetric hexameric rings of ClpX bind symmetric heptameric rings of ClpP and interact with protein substrates. Subunits in the ClpX hexamer assume a spiral conformation and interact with two-residue segments of substrate in the axial channel, as observed for other AAA+ proteases and protein-remodeling machines. Strictly sequential models of ATP hydrolysis and a power stroke that moves two residues of the substrate per translocation step have been inferred from these structural features for other AAA+ unfoldases, but biochemical and single-molecule biophysical studies indicate that ClpXP operates by a probabilistic mechanism in which five to eight residues are translocated for each ATP hydrolyzed. We propose structure-based models that could account for the functional results.
MIT Department
Massachusetts Institute of Technology. Department of Biology
Terms of Use
Creative Commons Attribution 4.0 International license
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DOI of Published Version
https://doi.org/10.7554/ELIFE.52774
