Role of the N-terminal domain of the chaperone ClpX in the recognition and degradation of lambda phage protein O

J Phys Chem B. 2012 Jun 14;116(23):6717-24. doi: 10.1021/jp212024b. Epub 2012 Mar 6.


The ClpXP ATPase-protease complex is a key element of the protein quality control machinery in the cell. ClpX consists of a zinc-binding domain (ZBD) that forms dimers and a AAA(+) domain that arranges into a hexamer in an ATP-dependent manner. Here, we report the binding site of the ClpX substrate λ phage protein O (λO) on ZBD(2) in ClpX using NMR and mutagenesis analysis. λO protein was found to interact with a hydrophobic patch on the larger surface of ZBD(2). The affinity of λO toward ZBD(2) was investigated using a quantitative optical biosensor method of dual polarization interferometry. The data suggest overlapping binding sites of λO and the ClpX cofactor SspB on the ZBD(2). Interestingly, a single key mutation in ZBD was found to enhance the ClpXP-dependent degradation of λO.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Endopeptidase Clp / chemistry
  • Endopeptidase Clp / genetics
  • Endopeptidase Clp / metabolism*
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Hydrophobic and Hydrophilic Interactions
  • Molecular Chaperones / chemistry
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism*
  • Mutagenesis
  • Nuclear Magnetic Resonance, Biomolecular
  • Protein Interaction Domains and Motifs
  • Surface Properties
  • Thermodynamics
  • Viral Proteins / chemistry
  • Viral Proteins / metabolism*


  • Escherichia coli Proteins
  • Molecular Chaperones
  • O protein, Bacteriophage lambda
  • Viral Proteins
  • ClpXP protease, E coli
  • Endopeptidase Clp