Contribution of DNA conformation and topology in right-handed DNA wrapping by the Bacillus subtilis LrpC protein.
The Bacillus subtilis LrpC protein belongs to the Lrp/AsnC family of transcriptional regulators. It binds the upstream region of the lrpC gene and autoregulates its expression. In this study, we have dissected the mechanisms that govern the interaction of LrpC with DNA by electrophoretic mobility shift assay, electron microscopy, and atomic force microscopy. LrpC is a structure-specific DNA binding protein that forms stable complexes with curved sequences containing phased A tracts and wraps DNA to form spherical, nucleosome-like structures. Formation of such wraps, initiated by cooperative binding of LrpC to DNA, results from optimal protein/protein interactions specified by the DNA conformation. In addition, we have demonstrated that LrpC constrains positive supercoils by wrapping the DNA in a right-handed superhelix, as visualized by electron microscopy.
Beloin
Christophe
C
Institut de Génétique et Microbiologie, Université Paris XI, Unité Mixte Recherche 8621, Bâtiment 360, 91405 Orsay Cedex, France.
Jeusset
Josette
J
Revet
Bernard
B
Mirambeau
Gilles
G
Le Hégarat
Francoise
F
Le Cam
Eric
E
D001412:Bacillus subtilis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D004269:DNA, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D051756:Leucine-Responsive Regulatory Protein; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D014157:Transcription Factors
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D051756:Leucine-Responsive Regulatory Protein