Regulation of the lic operon of Bacillus subtilis and characterization of potential phosphorylation sites of the LicR regulator protein by site-directed mutagenesis.
The lic operon of Bacillus subtilis is required for the transport and degradation of oligomeric beta-glucosides, which are produced by extracellular enzymes on substrates such as lichenan or barley glucan. The lic operon is transcribed from a sigma(A)-dependent promoter and is inducible by lichenan, lichenan hydrolysate, and cellobiose. Induction of the operon requires a DNA sequence with dyad symmetry located immediately upstream of the licBCAH promoter. Expression of the lic operon is positively controlled by the LicR regulator protein, which contains two potential helix-turn-helix motifs, two phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) regulation domains (PRDs), and a domain similar to PTS enzyme IIA (EIIA). The activity of LicR is stimulated by modification (probably phosphorylation) of both PRD-I and PRD-II by the general PTS components and is negatively regulated by modification (probably phosphorylation) of its EIIA domain by the specific EII(Lic) in the absence of oligomeric beta-glucosides. This was shown by the analysis of licR mutants affected in potential phosphorylation sites. Moreover, the lic operon is subject to carbon catabolite repression (CCR). CCR takes place via a CcpA-dependent mechanism and a CcpA-independent mechanism in which the general PTS enzyme HPr is involved.
Tobisch
S
S
Institut für Mikrobiologie und Molekularbiologie, Ernst-Moritz-Arndt-Universität Greifswald, D-17487 Greifswald, Germany.
Stülke
J
J
Hecker
M
M
D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins; D002874:Chromosome Mapping; D004268:DNA-Binding Proteins / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D005816:Genetic Complementation Test; D005936:Glucans / Q000494:pharmacology; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism; D007763:Lac Operon; D016297:Mutagenesis, Site-Directed; D009876:Operon / Q000235:genetics; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics; D012808:Sigma Factor / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D005936:Glucans; C120828:LicR protein, Bacillus subtilis; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D012808:Sigma Factor; D015534:Trans-Activators; C069286:catabolite control proteins, bacteria; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C083713:celD protein, Bacteria; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; D006026:Glycoside Hydrolases; C028020:licheninase; C015968:lichenin