title: Two distinct classes of FixJ binding sites defined by in vitro selection.
abstract: The phosphorylated FixJ transcriptional activator is key to nitrogen fixation in Sinorhizobium meliloti, switching both the nifA and fixK genes on. Previously no consensus picture emerged concerning the nature of FixJ binding sites. Here we used in vitro DNA selection in order to systematically characterise FixJ binding sequences. This led to the definition of two classes of sites. Class I sites share the CTAAGTAGTTTCCC sequence found in the fixK promoter, whereas class II sites are defined by a GTAMGTAG consensus octamer. Our results indicate that FixJ approximately P binds DNA following two distinct binding modes.
authors.affiliation: Laboratoire de Biologie Moléculaire des Relations Plantes-Microorganismes, UMR 215 INRA-CNRS, Chemin de Borde-Rouge, P.O. Box 27, Castanet-Tolosan, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Ferrières
authors.forename: Daniel
authors.initials: D
authors.lastname: Kahn
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence / Q000502:physiology; D001665:Binding Sites; D004269:DNA, Bacterial / Q000032:analysis; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000502:physiology*; D016962:Sinorhizobium meliloti / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D015534:Trans-Activators; C066628:FixK protein, Bacteria; C069289:FixJ protein, Bacteria