The HPr protein of the phosphotransferase system links induction and catabolite repression of the Bacillus subtilis levanase operon.
The LevR protein is the activator of expression of the levanase operon of Bacillus subtilis. The promoter of this operon is recognized by RNA polymerase containing the sigma 54-like factor sigma L. One domain of the LevR protein is homologous to activators of the NtrC family, and another resembles antiterminator proteins of the BglG family. It has been proposed that the domain which is similar to antiterminators is a target of phosphoenolpyruvate:sugar phosphotransferase system (PTS)-dependent regulation of LevR activity. We show that the LevR protein is not only negatively regulated by the fructose-specific enzyme IIA/B of the phosphotransferase system encoded by the levanase operon (lev-PTS) but also positively controlled by the histidine-containing phosphocarrier protein (HPr) of the PTS. This second type of control of LevR activity depends on phosphoenolpyruvate-dependent phosphorylation of HPr histidine 15, as demonstrated with point mutations in the ptsH gene encoding HPr. In vitro phosphorylation of partially purified LevR was obtained in the presence of phosphoenolpyruvate, enzyme I, and HPr. The dependence of truncated LevR polypeptides on stimulation by HPr indicated that the domain homologous to antiterminators is the target of HPr-dependent regulation of LevR activity. This domain appears to be duplicated in the LevR protein. The first antiterminator-like domain seems to be the target of enzyme I and HPr-dependent phosphorylation and the site of LevR activation, whereas the carboxy-terminal antiterminator-like domain could be the target for negative regulation by the lev-PTS.
Stülke
J
J
Unité de Biochimie Microbienne, Institut Pasteur, URA 1300 du Centre National de la Recherche Scientifique (CNRS), Paris, France.
Martin-Verstraete
I
I
Charrier
V
V
Klier
A
A
Deutscher
J
J
Rapoport
G
G
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics*; D001426:Bacterial Proteins / Q000378:metabolism; D004790:Enzyme Induction; D004794:Enzyme Repression; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006026:Glycoside Hydrolases / Q000235:genetics*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009876:Operon; D010728:Phosphoenolpyruvate / Q000378:metabolism; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017852:Phosphotransferases (Nitrogenous Group Acceptor) / Q000378:metabolism; D017354:Point Mutation; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism
D001426:Bacterial Proteins; D014157:Transcription Factors; C067962:LevR protein, Bacillus subtilis; D010728:Phosphoenolpyruvate; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C030182:phosphocarrier protein HPr; D017852:Phosphotransferases (Nitrogenous Group Acceptor); C022360:phosphoenolpyruvate-protein phosphotransferase; D006026:Glycoside Hydrolases; C021512:levanase