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

Piere Rodriguez-Aliaga; Luis Ramirez; Frank Kim; Carlos Bustamante; Andreas Martin

doi:10.1038/nsmb.3298

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

Nat Struct Mol Biol. 2016 Nov;23(11):974-981. doi: 10.1038/nsmb.3298. Epub 2016 Sep 26.

Authors

Piere Rodriguez-Aliaga^{1

2

3}, Luis Ramirez^{1

3}, Frank Kim¹, Carlos Bustamante^{1

2

3

4

5

6

7

8}, Andreas Martin^{2

3

4

7}

Affiliations

¹ Jason L. Choy Laboratory of Single-Molecule Biophysics, University of California at Berkeley, Berkeley, California, USA.
² Biophysics Graduate Group, University of California at Berkeley, Berkeley, California, USA.
³ Institute for Quantitative Biosciences-QB3, University of California at Berkeley, Berkeley, California, USA.
⁴ Department of Molecular &Cell Biology, University of California at Berkeley, Berkeley, California, USA.
⁵ Department of Chemistry, University of California at Berkeley, Berkeley, California, USA.
⁶ Department of Physics, University of California at Berkeley, Berkeley, California, USA.
⁷ Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, California, USA.
⁸ Kavli Energy Nanosciences Institute, University of California at Berkeley, Berkeley, California, USA.

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 motor power generation, the coupling between chemical and mechanical tasks, and the efficiency of protein processing. Conformational resetting of these loops between consecutive bursts appears to determine ADP release from individual ATPase subunits and the overall duration of the motor's cycle.

MeSH terms

ATPases Associated with Diverse Cellular Activities
Adenosine Diphosphate / metabolism
Adenosine Triphosphatases / chemistry
Adenosine Triphosphatases / metabolism
Adenosine Triphosphate / metabolism*
Endopeptidase Clp / chemistry
Endopeptidase Clp / metabolism*
Escherichia coli / chemistry
Escherichia coli / metabolism*
Escherichia coli Proteins / chemistry
Escherichia coli Proteins / metabolism*
Hydrolysis
Kinetics
Models, Molecular
Molecular Chaperones / chemistry
Molecular Chaperones / metabolism
Protein Binding
Protein Conformation
Protein Unfolding
Substrate Specificity

Substances

Escherichia coli Proteins
Molecular Chaperones
Adenosine Diphosphate
Adenosine Triphosphate
ClpXP protease, E coli
Endopeptidase Clp
Adenosine Triphosphatases
ClpX protein, E coli
ATPases Associated with Diverse Cellular Activities

Abstract

MeSH terms

Substances

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