2MAO: NMR structure of region 2 of E. coli sigmaE

Bacterial transcription is controlled by sigma factors, the RNA polymerase subunits that act as initiation factors. Although a single housekeeping sigma factor enables transcription from thousands of promoters, environmentally induced sigma factors redirect gene expression toward small regulons to carry out focused responses. Using structural and functional analyses, we determined the molecular basis of -10 promoter element recognition by Escherichia coli sigma(E), which revealed an unprecedented way to achieve promoter melting. Group IV sigma factors induced strand separation at the -10 element by flipping out a single nucleotide from the nontemplate-strand DNA base stack. Unambiguous selection of this critical base was driven by a dynamic protein loop, which can be substituted to modify specificity of promoter recognition. This mechanism of promoter melting explains the increased promoter-selection stringency of environmentally induced sigma factors.
PDB ID: 2MAODownload
MMDB ID: 117562
PDB Deposition Date: 2013/7/16
Updated in MMDB: 2018/05
Experimental Method:
solution nmr
Source Organism:
Similar Structures:
Biological Unit for 2MAO: monomeric; determined by author
Molecular Components in 2MAO
Label Count Molecule
Protein (1 molecule)
RNA Polymerase Sigma Factor
Molecule annotation
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Citing MMDB