Genomic analysis of LexA binding reveals the permissive nature of the Escherichia coli genome and identifies unconventional target sites

Article Abstract:

Chromatin immunoprecipitation and high-density oligonucleotide microarrays are combined to define the in-vivo DNA targets of the LexA transcriptional repressor in 'Escherichia coli'. It is indicated that the 'E. coli' genome is permissive to transcription factor biding and the permissive nature of the 'E. coli' has important consequences for the nature of transcriptional regulatory proteins, biological specificity, and evolution.

Observations, DNA microarrays

A zinc-binding site in the largest subunit of DNA-dependent RNA polymerase is involved in enzyme assembly

Article Abstract:

A zinc-binding site in the largest subunit of DNA-dependent RNA polymerase (RNAP) is discussed. The site is involved in enzyme assembly. Four cysteine residues in the largest Escherichia coli RNAP subunit have been found. They coordinate two zinc ions closely associated with RNAP. Involvement of zinc in the RNAP assembly may be unique to eubacterial-type enzymes. Zinc acts as a molecular chaperone.

Statistical Data Included, Physiological aspects, Enzymes, RNA polymerases, Cytochemistry, Mutation (Biology), Mutation, Zinc in the body, Zinc (Nutrient)

A two-component phosphotransfer network involving ArcB, ArcA, and RssB coordinates synthesis and proteolysis of sigma(super s) (RpoS) in E. coli

Article Abstract:

The general stress sigma factor sigma (super s) (RpoS) in Escherichia coli is controlled during transcription, translation and proteolysis. The study illustrates that the ArcB/ArcA/RssB phosphotranfer network maintains low sigma (super s) levels in nonstressed cells by inhibiting rpoS transcription and promoting sigma (super s) proteolysis.

Proteolysis