title: The psi operon of Rhizobium leguminosarum biovar phaseoli: identification of two genes whose products are located at the bacterial cell surface.
abstract: We have delineated three short open reading frames, psiA, ORF-P and psiB within the psi operon of Rhizobium leguminosarum biovar phaseoli. psiA, in a multi-copy plasmid, causes inhibition of exopolysaccharide synthesis in R. leguminosarum. In addition, the suppression of exopolysaccharide synthesis due to the multi-copy psiA caused R. leguminosarum strains to stain with the dye calcofluor, a response that does not occur with wild-type strains of this species. Insertions of a defective phoA gene (lacking its promoter, ribosomal binding site and leader sequence) into psiA and psiB were isolated and the precise locations of the insertions were established. PsiA-PhoA and PsiB-PhoA protein fusions were found to express alkaline phosphatase activity indicating that PsiA and PsiB span the inner membrane or are translocated across it.
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich, UK.
authors.forename: M L
authors.initials: ML
authors.lastname: Mimmack
authors.forename: D
authors.initials: D
authors.lastname: Borthakur
authors.forename: M A
authors.initials: MA
authors.lastname: Jones
authors.forename: J A
authors.initials: JA
authors.lastname: Downie
authors.forename: A W
authors.initials: AW
authors.lastname: Johnston
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D001557:Benzenesulfonates; D002451:Cell Compartmentation; D005798:Genes, Bacterial / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009876:Operon / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D012097:Repressor Proteins; D016961:Rhizobium leguminosarum / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013194:Staining and Labeling; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D001557:Benzenesulfonates; D008565:Membrane Proteins; C058074:PsiB protein, Bacteria; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C088288:psiA protein, Rhizobium leguminosarum; C007061:C.I. Fluorescent Brightening Agent 28; D000469:Alkaline Phosphatase