title: PrcR, a PucR-type transcriptional activator, is essential for proline utilization and mediates proline-responsive expression of the proline utilization operon putBCP in Bacillus subtilis.
abstract: The soil bacterium Bacillus subtilis can utilize exogenous proline as a sole nitrogen or carbon source. The proline-inducible putBCP (formerly ycgMNO) operon encodes proteins responsible for proline uptake and two-step oxidation of proline to glutamate. We now report that a gene (formerly ycgP, now designated prcR) located downstream of the putBCP operon is essential for B. subtilis cells to utilize proline as a sole nitrogen or carbon source. Disruption of the prcR gene also abolished proline induction of putB transcription. prcR expression is not subject to autoregulation and proline induction. The PrcR protein shows no significant amino acid sequence similarity to the known transcriptional activators for proline utilization genes of other bacteria, but it does show partial amino acid sequence similarity to the transcriptional regulator PucR for the purine degradation genes of B. subtilis. PrcR orthologues of unknown function are present in some other Bacillus species. Primer-extension analysis suggests that both putB and prcR are transcribed by a σ(A)-dependent promoter. Deletion and mutation analysis revealed that an inverted repeat (5'-TTGTGG-N5-CCACAA-3') centred at position -76 relative to the transcriptional initiation site of putB is essential for putB expression. Electrophoretic mobility shift assays showed that the purified His-tagged PrcR was capable of binding specifically to this inverted repeat. Altogether, these results suggest that PrcR is a PucR-type transcriptional activator that mediates expression of the B. subtilis putBCP operon in response to proline availability.
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan, ROC.
authors.forename: Shih-Chien
authors.initials: SC
authors.lastname: Huang
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan, ROC.
authors.forename: Ta-Hui
authors.initials: TH
authors.lastname: Lin
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan, ROC.
authors.forename: Gwo-Chyuan
authors.initials: GC
authors.lastname: Shaw
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D001665:Binding Sites; D002244:Carbon / Q000378:metabolism; D004252:DNA Mutational Analysis; D024202:Electrophoretic Mobility Shift Assay; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D026901:Membrane Transport Proteins / Q000096:biosynthesis*; D009584:Nitrogen / Q000378:metabolism; D009876:Operon; D011392:Proline / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D026901:Membrane Transport Proteins; D012808:Sigma Factor; D015534:Trans-Activators; D002244:Carbon; D011392:Proline; D009584:Nitrogen