Large nucleotide-dependent movement of the N-terminal domain of the ClpX chaperone

EMBO J. 2006 Jul 26;25(14):3367-76. doi: 10.1038/sj.emboj.7601223. Epub 2006 Jun 29.


The ClpXP ATPase-protease complex is a major component of the protein quality control machinery in the cell. A ClpX subunit consists of an N-terminal zinc binding domain (ZBD) and a C-terminal AAA+ domain. ClpX oligomerizes into a hexamer with the AAA+ domains forming the base of the hexamer and the ZBDs extending out of the base. Here, we report that ClpX switches between a capture and a feeding conformation. ZBDs in ClpX undergo large nucleotide-dependent block movement towards ClpP and into the AAA+ ring. This motion is modulated by the ClpX cofactor, SspB. Evidence for this movement was initially obtained by the surprising observation that an N-terminal extension on ClpX is clipped by bound ClpP in functional ClpXP complexes. Protease-protection, crosslinking, and light scattering experiments further support these findings.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATPases Associated with Diverse Cellular Activities
  • Adenosine Triphosphatases / chemistry
  • Adenosine Triphosphatases / metabolism
  • Adenosine Triphosphatases / physiology
  • Bacterial Proteins / metabolism
  • Biological Transport, Active / physiology
  • Endopeptidase Clp / chemistry*
  • Endopeptidase Clp / metabolism
  • Endopeptidase Clp / physiology*
  • Escherichia coli / enzymology
  • Escherichia coli / physiology
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / metabolism
  • Escherichia coli Proteins / physiology
  • Molecular Chaperones / chemistry
  • Molecular Chaperones / metabolism
  • Molecular Chaperones / physiology
  • Nucleotides / physiology*
  • Peptide Fragments / chemistry*
  • Peptide Fragments / physiology*
  • Protein Structure, Tertiary
  • Serine Endopeptidases / metabolism


  • Bacterial Proteins
  • Escherichia coli Proteins
  • Molecular Chaperones
  • Nucleotides
  • Peptide Fragments
  • Serine Endopeptidases
  • ClpP protease, E coli
  • ClpP protein, Streptococcus pneumoniae
  • Endopeptidase Clp
  • Adenosine Triphosphatases
  • ClpX protein, E coli
  • ATPases Associated with Diverse Cellular Activities