1OR7: Crystal Structure Of Escherichia Coli Sigmae With The Cytoplasmic Domain Of Its Anti-Sigma Rsea

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.
PDB ID: 1OR7Download
MMDB ID: 22816
PDB Deposition Date: 2003/3/12
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 1OR7: dimeric; determined by author and by software (PISA)
Molecular Components in 1OR7
Label Count Molecule
Proteins (2 molecules)
RNA Polymerase Sigma-e Factor(Gene symbol: rpoE)
Molecule annotation
Sigma-e Factor Negative Regulatory Protein(Gene symbol: rseA)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB