Substrate-translocating loops regulate mechanochemical coupling and power production in AAA+ protease ClpXP.

ABSTRACT: ATP-dependent proteases of the AAA+ family, including Escherichia coli ClpXP and the eukaryotic proteasome, contribute to maintenance of cellular proteostasis. ClpXP unfolds and translocates substrates into an internal degradation chamber, using cycles of alternating dwell and burst phases. The ClpX motor performs chemical transformations during the dwell and translocates the substrate in increments of 1-4 nm during the burst, but the processes occurring during these phases remain unknown. Here we characterized the complete mechanochemical cycle of ClpXP, showing that ADP release and ATP binding occur nonsequentially during the dwell, whereas ATP hydrolysis and phosphate release occur during the burst. The highly conserved translocating loops within the ClpX pore are optimized to maximize

SUBMITTER: Rodriguez-Aliaga P 

PROVIDER: S-EPMC5467750 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature