title: Phosphorylation of either crh or HPr mediates binding of CcpA to the bacillus subtilis xyn cre and catabolite repression of the xyn operon.
abstract: Carbon catabolite repression (CCR) of several Bacillus subtilis catabolic genes is mediated by ATP-dependent phosphorylation of Ser46 of the histidine-containing protein (HPr), a phosphocarrier protein of the phosphoenolpyruvate (PEP): sugar phosphotransferase system. A recently discovered HPr-like protein of B. subtilis, Crh, cannot be phosphorylated by PEP and enzyme I but becomes phosphorylated at Ser46 by the ATP-dependent, metabolite-activated HPr kinase. Genetic data suggested that Crh is also implicated in CCR. We here demonstrate that in a ptsH1 crh1 mutant, in which Ser46 of both HPr and Crh is replaced with an alanyl residue, expression of the beta-xylosidase-encoding xynB gene was completely relieved from CCR. No effect on CCR could be observed in strains carrying the crh1 allele, suggesting that under the experimental conditions P-Ser-HPr can substitute for P-Ser-Crh in CCR. By contrast, a ptsH1 mutant was slightly relieved from CCR of xynB, indicating that P-Ser-Crh can substitute only partly for P-Ser-HPr. Mapping experiments allowed us to identify the xyn promoter and a catabolite responsive element (cre) located 229 bp downstream of the transcription start point. Using DNase I footprinting experiments, we could demonstrate that similar to P-Ser-HPr, P-Ser-Crh stimulates binding of CcpA to the xyn cre. Fructose 1,6-bisphosphate was found to strongly enhance binding of the P-Ser-HPr/CcpA and P-Ser-Crh/CcpA complexes to the xyn cre, but had no effect on binding of CcpA alone.
authors.affiliation: Institut de Biologie et Chimie des Protéines, CNRS UPR 412, Lyon Cedex 07, F-69367, France.
authors.forename: A
authors.initials: A
authors.lastname: Galinier
authors.forename: J
authors.initials: J
authors.lastname: Deutscher
authors.forename: I
authors.initials: I
authors.lastname: Martin-Verstraete
mesh_terms: D000409:Alanine / Q000737:chemistry; D019943:Amino Acid Substitution; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism*; D043364:Endo-1,4-beta Xylanases; D005246:Feedback; D005635:Fructosediphosphates / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009876:Operon / Q000187:drug effects*; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000737:chemistry / Q000378:metabolism*; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D012097:Repressor Proteins / Q000378:metabolism*; D012694:Serine / Q000737:chemistry; D014158:Transcription, Genetic; D014995:Xylosidases / Q000096:biosynthesis / Q000235:genetics*; D001617:beta-Glucosidase / Q000096:biosynthesis / Q000235:genetics*