This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Fux, L. Articles by Amster-Choder, O. Search for Related Content PubMed PubMed Citation Articles by Fux, L. Articles by Amster-Choder, O. Pubmed/NCBI databases Gene GEO Profiles

 Previous Article  |  Next Article 

Journal of Bacteriology, October 2004, p. 6775-6781, Vol. 186, No. 20
0021-9193/04/$08.00+0     DOI: 10.1128/JB.186.20.6775-6781.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Modulation of Monomer Conformation of the BglG Transcriptional Antiterminator from Escherichia coli

Liat Fux, Anat Nussbaum-Shochat, Livnat Lopian, and Orna Amster-Choder^*

Department of Molecular Biology, The Hebrew University-Hadassah Medical School, Jerusalem, Israel

Received 20 May 2004/ Accepted 17 July 2004

The BglG protein positively regulates expression of the bgl operon in Escherichia coli by binding as a dimer to the bgl transcript and preventing premature termination of transcription in the presence of ß-glucosides. BglG activity is negatively controlled by BglF, the ß-glucoside phosphotransferase, which reversibly phosphorylates BglG according to ß-glucoside availability, thus modulating its dimeric state. BglG consists of an RNA-binding domain and two homologous domains, PRD1 and PRD2. Based on structural studies of a BglG homologue, the two PRDs fold similarly, and the interactions within the dimer are PRD1-PRD1 and PRD2-PRD2. We have recently shown that the affinity between PRD1 and PRD2 of BglG is high, and a fraction of the BglG monomers folds in the cell into a compact conformation, in which PRD1 and PRD2 are in close proximity. We show here that both BglG forms, the compact and noncompact, bind to the active site-containing domain of BglF, IIB^bgl, in vitro. The interaction of BglG with IIB^bgl or BglF is mediated by PRD2. Both BglG forms are detected as phosphorylated proteins after in vitro phosphorylation with IIB^bgl and are dephosphorylated by BglF in vitro in the presence of ß-glucosides. Nevertheless, genetic evidence indicates that the interaction of IIB^bgl and BglF with the compact form is seemingly less favorable. Using in vivo cross-linking, we show that BglF enhances folding of BglG into a compact conformation, whereas the addition of ß-glucosides reduces the amount of this form. Based on these results we suggest a model for the modulation of BglG conformation and activity by BglF.

---

* Corresponding author. Mailing address: Department of Molecular Biology, The Hebrew University-Hadassah Medical School, P. O. Box 12272, Jerusalem 91120, Israel. Phone: 972 2 675 8460. Fax: 972 2 678 4010. E-mail: amster{at}cc.huji.ac.il.

---

Journal of Bacteriology, October 2004, p. 6775-6781, Vol. 186, No. 20
0021-9193/04/$08.00+0     DOI: 10.1128/JB.186.20.6775-6781.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Monderer-Rothkoff, G., Amster-Choder, O. (2007). Genetic Dissection of the Divergent Activities of the Multifunctional Membrane Sensor BglF. J. Bacteriol. 189: 8601-8615 [Abstract] [Full Text]  
• Chang, W., Small, D. A., Toghrol, F., Bentley, W. E. (2006). Global Transcriptome Analysis of Staphylococcus aureus Response to Hydrogen Peroxide. J. Bacteriol. 188: 1648-1659 [Abstract] [Full Text]