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Biochem Biophys Res Commun. 2015 Aug 14;464(1):324-9. doi: 10.1016/j.bbrc.2015.06.152. Epub 2015 Jun 26.

Multiple allosteric effectors control the affinity of DasR for its target sites.

Author information

1
Center for Protein Engineering, Institut de chimie B6a, University of Liège, B-4000 Liège, Belgium.
2
Molecular Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
3
Department of Oecotrophologie, Münster University of Applied Sciences, Corrensstr. 25, 48149 Münster, Germany.
4
Lehrstuhl für Biotechnik, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Henkestrasse 91, D-91052 Erlangen, Germany.
5
Center for Protein Engineering, Institut de chimie B6a, University of Liège, B-4000 Liège, Belgium. Electronic address: srigali@ulg.ac.be.

Abstract

The global transcriptional regulator DasR connects N-acetylglucosamine (GlcNAc) utilization to the onset of morphological and chemical differentiation in the model actinomycete Streptomyces coelicolor. Previous work revealed that glucosamine-6-phosphate (GlcN-6P) acts as an allosteric effector which disables binding by DasR to its operator sites (called dre, for DasR responsive element) and allows derepression of DasR-controlled/GlcNAc-dependent genes. To unveil the mechanism by which DasR controls S. coelicolor development, we performed a series of electromobility shift assays with histidine-tagged DasR protein, which suggested that N-acetylglucosamine-6-phosphate (GlcNAc-6P) could also inhibit the formation of DasR-dre complexes and perhaps even more efficiently than GlcN-6P. The possibility that GlcNAc-6P is indeed an efficient allosteric effector of DasR was further confirmed by the high and constitutive activity of the DasR-repressed nagKA promoter in the nagA mutant, which lacks GlcNAc-6P deaminase activity and therefore accumulates GlcNAc-6P. In addition, we also observed that high concentrations of organic or inorganic phosphate enhanced binding of DasR to its recognition site, suggesting that the metabolic status of the cell could determine the selectivity of DasR in vivo, and hence its effect on the expression of its regulon.

KEYWORDS:

Allosteric effector; DNA-protein interaction; Gene expression regulation; Ligand; Nacetylglucosamine

PMID:
26123391
DOI:
10.1016/j.bbrc.2015.06.152
[Indexed for MEDLINE]
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