DNA Binding Properties of thehfqGene Product ofEscherichia coli

Interactions of the Non-coding RNA DsrA and RpoS mRNA with the 30 S Ribosomal Subunit

“…We expected that Hfq might be associated with our 30 S subunits and be involved in DsrA ncRNA binding. Hfq specifically binds a 3Ј domain in DsrA (26) and has been shown to interact strongly with DNA sequences (29,30). Western blot analysis using Hfq antisera demonstrates it is not present at detectable levels in our 30 S subunit preparations and therefore is not responsible for the interaction of the molecules with the 30 S subunit in our in vitro assays.…”

“…DsrA binds to the protein Hfq (21,26), which is associated with ribosomes in E. coli cells (28). Hfq interacts with a variety of RNA and DNA sequences (29,30). Western blotting analysis using Hfq antisera (the kind gift of Gisela Storz) demonstrated no detectable levels of Hfq in either 30 S ribosomal subunit or 70 S ribosome preparations (data not shown), strongly suggesting that binding of the DsrA to the 30 S subunit resulted from an interaction of the ncRNA with 16 S rRNA or small subunit ribosomal proteins.…”

Twelve Species of the Nucleoid-associated Protein from Escherichia coli

“…When nonspecific DNA-binding proteins were analyzed using such DNA fragment mixtures, the longer DNA fragments tend to shift at lower protein concentrations than the shorter fragments (32). The order of DNA binding affinity measured in this system was essentially the same at least among the nonspecific DNA-binding proteins (data not shown).…”

The stoichiometry of the Escherichia coli Hfq protein bound to RNA

“…E. coli Hfq and its bacterial homologs have been implicated in various facets of bacterial metabolism, including stressinduced sRNA regulation of mRNA translation as well as mRNA stability. In addition to its well-documented interaction with RNA, Hfq has been found associated with DNA (Takada et al 1997;Azam et al 2000;Updegrove et al 2010) as well as a number of proteins (Butland et al 2005). The nature of Hfq's interactions with DNA and many of the proteins are not well understood; however, there is increasing recognition that they may reflect additional functions of Hfq (Le Derout et al 2010).…”