Modulation of transcription antitermination in the bgl operon of Escherichia coli by the PTS

Hadas Raveh, Livnat Lopian, Anat Nussbaum-Shochat, Andrew Wright, Orna Amster-Choder*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


BglG, which regulates expression of the β-glucoside utilization (bgl) operon in Escherichia coli, represents a family of RNA-binding transcriptional antiterminators that positively regulate transcription of sugar utilization genes in Gram-negative and Gram-positive organisms. BglG is negatively regulated by the β-glucoside phosphotransferase, BglF, by means of phosphorylation and physical association, and it is positively regulated by the general phosphoenolpyruvate phosphotransferase system (PTS) proteins, enzyme I (EI) and HPr. We studied the positive regulation of BglG both in vitro and in vivo. Here, we show that although EI and HPr are essential for BglG activity, this mode of activation does not require phosphorylation of BglG by HPr, as opposed to the phosphorylation-mediated activation of many BglG-like antiterminators in Gram-positive organisms. The effect of EI and HPr on BglG is not mediated by BglF. Nevertheless, the release of BglG from BglF, which is stimulated by the extracellular sugar in a sugar uptake-independent manner, is a prerequisite for BglG activation. Taken together, the results indicate that activation of BglG is a 2-stage process: a sugar-stimulated release from the membrane-bound sugar sensor followed by a phosphorylation-independent stimulatory effect exerted by the general PTS proteins.

Original languageAmerican English
Pages (from-to)13523-13528
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number32
StatePublished - 11 Aug 2009


  • Bgl system
  • E. coli


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