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The Role of LRP and H-NS in Transcription Regulation: Involvement of Synergism, Allostery and Macromolecular Crowding
- Source :
-
Journal of Molecular Biology . Feb2007, Vol. 366 Issue 3, p900-915. 16p. - Publication Year :
- 2007
-
Abstract
- Abstract: LRP has recently been shown to interact with the regulatory regions of bacterial ribosomal RNA promoters. Here we study details of the LRP–rDNA interaction by gel retardation and high-resolution footprinting techniques. We show that a second regulator for rRNA transcription, H-NS, facilitates the formation of a higher-order LRP–nucleoprotein complex, probably acting transiently as a DNA chaperone. The macromolecular crowding substance ectoine stabilizes the formation of this dynamic complex, while the amino acid leucine, as a metabolic effector, has the opposite effect. DNase I and hydroxyl radical footprint experiments with LRP–DNA complexes reveal a periodic change of the target DNA structure, which implies extensive DNA wrapping reaching into the promoter core region. We show furthermore that LRP binding is able to constrain supercoils, providing a link between DNA topology and regulation. The results support the conclusion that the bacterial DNA-binding protein LRP, assisted by H-NS, forms a repressive nucleoprotein structure involved in regulation of rRNA transcription. The formation of this regulatory structure appears to be directly affected by environmental changes. [Copyright &y& Elsevier]
- Subjects :
- *GENETIC transcription
*ALLOSTERIC enzymes
*MACROMOLECULES
*RNA
Subjects
Details
- Language :
- English
- ISSN :
- 00222836
- Volume :
- 366
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- Journal of Molecular Biology
- Publication Type :
- Academic Journal
- Accession number :
- 23876962
- Full Text :
- https://doi.org/10.1016/j.jmb.2006.11.067