title: A transcription factor with a leucine-zipper motif involved in light-dependent inhibition of expression of the puf operon in the photosynthetic bacterium Rhodobacter sphaeroides.
abstract: In the purple nonsulfur photosynthetic bacterium Rhodobacter sphaeroides the synthesis of components of the photosystem is regulated in response to oxygen tension and light intensity. We have purified and cloned a trans-acting protein (SPB) that binds to the promoter region of the puf operon, which encodes the apoproteins of light-harvesting complex I and the reaction center. The SPB was composed of a single polypeptide with an apparent molecular mass of 15.0 kDa. The nucleotide sequence of the spb gene was determined. The gene encoded 104 amino acid residues, which correspond to a molecular mass of 11.5 kDa. SPB exhibited 53% homology to HvrA in Rhodobacter capsulatus. The deduced amino acid sequence indicated that SPB contained a region with homology to the leucine-zipper motif of c-JUN, a transcription factor in eukaryotes, and SPB also had a DNA-binding domain on the amino-terminal side of the leucine-zipper motif. The leucine-zipper motif of SPB might contribute to the formation of a dimer. Northern analysis indicated that spb was constitutively and monocistronically transcribed in R. sphaeroides, irrespective of growth conditions. Structural and functional differences between SPB and HvrA are discussed.
authors: Department of Biological Sciences, Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan.
authors: H
authors: H
authors: Shimada
authors: T
authors: T
authors: Wada
authors: H
authors: H
authors: Handa
authors: H
authors: H
authors: Ohta
authors: H
authors: H
authors: Mizoguchi
authors: K
authors: K
authors: Nishimura
authors: T
authors: T
authors: Masuda
authors: Y
authors: Y
authors: Shioi
authors: K
authors: K
authors: Takamiya
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D015870:Gene Expression / Q000528:radiation effects; D005798:Genes, Bacterial; D016350:Leucine Zippers / Q000235:genetics; D008027:Light; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins; D054778:NM23 Nucleoside Diphosphate Kinases; D009701:Nucleoside-Diphosphate Kinase; D015345:Oligonucleotide Probes / Q000235:genetics; D009876:Operon / Q000528:radiation effects; D010788:Photosynthesis; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics; D012242:Rhodobacter sphaeroides / Q000235:genetics* / Q000528:radiation effects; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D054778:NM23 Nucleoside Diphosphate Kinases; D015345:Oligonucleotide Probes; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors; D009701:Nucleoside-Diphosphate Kinase; D020559:Monomeric GTP-Binding Proteins