Article
- The EMBO Journal (2005) 24, 283 - 293
- doi:10.1038/sj.emboj.7600517
Published online: 16 December 2004
Subject Categories:
Escherichia coli dihydroxyacetone kinase controls gene expression by binding to transcription factor DhaR
Christoph Bächler1, Philipp Schneider1, Priska Bähler1, Ariel Lustig2 and Bernhard Erni1
- Departement für Chemie und Biochemie, Universität Bern, Bern, Switzerland
- Division of Biophysics, Biozentrum, University of Basel, Basel, Switzerland
Correspondence to:
Bernhard Erni, Departement für Chemie und Biochemie, Universität Bern, Freiestr. 3, 3012 Bern, Switzerland. Tel.: +41 31 631 4346; Fax: +41 31 631 4887; E-mail: erni@ibc.unibe.ch
Received 12 July 2004; Accepted 22 November 2004
Abstract
Dihydroxyacetone (Dha) kinases are a sequence-conserved family of enzymes, which utilize either ATP (in animals, plants, bacteria) or the bacterial phosphoenolpyruvate carbohydrate phosphotransferase system (PTS) as a source of high-energy phosphate. The PTS-dependent kinase of Escherichia coli consists of three subunits: DhaK contains the Dha binding site, DhaL contains ADP as cofactor for the double displacement of phosphate from DhaM to Dha, and DhaM provides a phospho-histidine relay between the PTS and DhaL
ADP. DhaR is a transcription activator belonging to the AAA+ family of enhancer binding proteins. It stimulates transcription of the dhaKLM operon from a sigma70 promoter and autorepresses dhaR transcription. Genetic and biochemical studies indicate that the enzyme subunits DhaL and DhaK act antagonistically as coactivator and corepressor of the transcription activator by mutually exclusive binding to the sensing domain of DhaR. In the presence of Dha, DhaL is dephosphorylated and DhaLADP displaces DhaK and stimulates DhaR activity. In the absence of Dha, DhaLADP is converted by the PTS to DhaLATP, which does not bind to DhaR.
Keywords:
- AAA+ ATPase,
- enhancer binding proteins,
- protein–protein interaction,
- PTS,
- transcription
