The Non-dominant AAA+ Ring in the ClpAP Protease Functions as an Anti-stalling Motor to Accelerate Protein Unfolding and Translocation
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1-s2.0-S2211124720301546-main.pdf
Description
Published version
Size
2.68 MB
Format
Adobe PDF
Checksum (MD5)
22909e935b12005330f56e274598e4c4
Author(s)
Kotamarthi, Hema Chandra
Sauer, Robert T
Baker, Tania A
Date Issued
2020
Journal
Cell Reports
Publisher
Elsevier BV
Version
Final published version
Abstract
© 2020 The Authors ATP-powered unfoldases containing D1 and D2 AAA+ rings play important roles in protein homeostasis, but uncertainty about the function of each ring remains. Here we use single-molecule optical tweezers to assay mechanical unfolding and translocation by a variant of the ClpAP protease containing an ATPase-inactive D1 ring. This variant displays substantial mechanical defects in both unfolding and translocation of protein substrates. Notably, when D1 is hydrolytically inactive, ClpAP often stalls for times as long as minutes, and the substrate can back-slip through the enzyme when ATP concentrations are low. The inactive D1 variant also has more difficulty traveling in the N-to-C direction on a polypeptide track than it does moving in a C-to-N direction. These results indicate that D1 normally functions as an auxiliary/regulatory motor to promote uninterrupted enzyme advancement that is fueled largely by the D2 ring.
MIT Department
Massachusetts Institute of Technology. Department of Biology
Howard Hughes Medical Institute
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivs License
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DOI of Published Version
https://doi.org/10.1016/J.CELREP.2020.01.110
