Crystal structure of Escherichia coli sigmaE with the cytoplasmic domain of its anti-sigma RseA

Mol Cell. 2003 Apr;11(4):1067-78. doi: 10.1016/s1097-2765(03)00148-5.


The sigma factors are the key regulators of bacterial transcription. ECF (extracytoplasmic function) sigma's are the largest and most divergent group of sigma(70) family members. ECF sigma's are normally sequestered in an inactive complex by their specific anti-sigma factor, which often spans the inner membrane. Here, we determined the 2 A resolution crystal structure of the Escherichia coli ECF sigma factor sigma(E) in an inhibitory complex with the cytoplasmic domain of its anti-sigma, RseA. Despite extensive sequence variability, the two major domains of sigma(E) are virtually identical in structure to the corresponding domains of other sigma(70) family members. In combination with a model of the sigma(E) holoenzyme and biochemical data, the structure reveals that RseA functions by sterically occluding the two primary binding determinants on sigma(E) for core RNA polymerase.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Binding Sites / physiology
  • Crystallography, X-Ray
  • Cytoplasm / metabolism
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / chemistry*
  • Gene Expression Regulation, Bacterial / genetics*
  • Genes, Regulator / genetics*
  • Macromolecular Substances
  • Membrane Proteins / chemistry*
  • Molecular Sequence Data
  • Molecular Structure
  • Protein Binding / physiology
  • Protein Structure, Secondary / physiology
  • Protein Structure, Tertiary / genetics
  • Sequence Homology, Amino Acid
  • Sigma Factor / chemistry*
  • Transcription Factors / chemistry*


  • Escherichia coli Proteins
  • Macromolecular Substances
  • Membrane Proteins
  • RseA protein, E coli
  • Sigma Factor
  • Transcription Factors
  • sporulation-specific sigma factors

Associated data

  • PDB/1OR7