Dispensable PDZ domain of Escherichia coli YaeL essential protease

Mol Microbiol. 2004 Apr;52(2):427-35. doi: 10.1111/j.1365-2958.2004.03985.x.


In Escherichia coli, adaptation to extra-cytoplasmic stress relies on sigma(E) activation to induce a rescue pathway. Under non-stressed conditions, sigma(E) is sequestered by the inner membrane protein RseA. Extra-cytoplasmic stress activates DegS-dependent cleavage of RseA, rendering RseA sensitive to further degradation by the YaeL protease. YaeL contains two motifs characteristic of a family of metallo-proteases, as well as a periplasmic PDZ domain. We report results of mutational analyses of the YaeL domains. Surprisingly, expression in a strain depleted for wild-type YaeL or YaeL variants having a 40 amino acid deletion of the PDZ domain or amino acid substitutions of conserved amino acids of the YaeL PDZ domain did not affect cell viability. The proteolytic activity against RseA of these YaeL variants became independent of DegS. These observations suggest that the YaeL PDZ domain exerts a negative control on YaeL activity. Rather than being involved in substrate recognition, the PDZ domain of YaeL is likely to act as an inhibitor of proteolytic activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs*
  • Amino Acid Sequence
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Binding Sites
  • Cloning, Molecular
  • DNA Mutational Analysis
  • Endopeptidases / chemistry*
  • Endopeptidases / genetics
  • Endopeptidases / metabolism*
  • Escherichia coli / genetics
  • Escherichia coli / growth & development
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Gene Expression Regulation, Bacterial
  • Membrane Proteins / chemistry*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Molecular Sequence Data
  • Mutagenesis
  • Mutation
  • Plasmids
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Transcription Factors / chemistry
  • Transcription Factors / metabolism*


  • Bacterial Proteins
  • DegS protein, Bacteria
  • Escherichia coli Proteins
  • Membrane Proteins
  • Recombinant Proteins
  • RseA protein, E coli
  • Transcription Factors
  • degS protein, Escherichia coli
  • Endopeptidases
  • RseP protein, E coli