Crystal structure of ClpA, an Hsp100 chaperone and regulator of ClpAP protease

J Biol Chem. 2002 Nov 29;277(48):46743-52. doi: 10.1074/jbc.M207796200. Epub 2002 Aug 29.


Escherichia coli ClpA, an Hsp100/Clp chaperone and an integral component of the ATP-dependent ClpAP protease, participates in regulatory protein degradation and the dissolution and degradation of protein aggregates. The crystal structure of the ClpA subunit reveals an N-terminal domain with pseudo-twofold symmetry and two AAA(+) modules (D1 and D2) each consisting of a large and a small sub-domain with ADP bound in the sub-domain junction. The N-terminal domain interacts with the D1 domain in a manner similar to adaptor-binding domains of other AAA(+) proteins. D1 and D2 are connected head-to-tail consistent with a cooperative and vectorial translocation of protein substrates. In a planar hexamer model of ClpA, built by assembling ClpA D1 and D2 into homohexameric rings of known structures of AAA(+) modules, the differences in D1-D1 and D2-D2 interfaces correlate with their respective contributions to hexamer stability and ATPase activity.

MeSH terms

  • Adenosine Diphosphate / metabolism
  • Adenosine Triphosphatases / chemistry*
  • Adenosine Triphosphatases / metabolism
  • Amino Acid Sequence
  • Crystallography, X-Ray
  • Endopeptidase Clp
  • Endopeptidases / metabolism*
  • Escherichia coli Proteins*
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Serine Endopeptidases / chemistry*
  • Serine Endopeptidases / metabolism
  • Static Electricity


  • Escherichia coli Proteins
  • Adenosine Diphosphate
  • Endopeptidases
  • Serine Endopeptidases
  • ClpA protease, E coli
  • Endopeptidase Clp
  • Adenosine Triphosphatases

Associated data

  • PDB/1K6K
  • PDB/1KSF