Molecular analysis of the interaction between the Bacillus subtilis trehalose repressor TreR and the tre operator.
The trehalose operon of Bacillus subtilis is subject to regulation by induction, mediated by the repressor TreR, and by carbon catabolite repression (CCR). For in vitro investigations, TreR from B. subtilis was overproduced and purified. Its molecular mass, as estimated by SDS-PAGE, is 27 kDa. Size fractionation under native conditions yielded a size estimate of 56 kDa, indicating that TreR exists as a dimer in its native state. Analysis of its interaction with various DNA fragments shows that TreR is able to recognize two tre operators with different efficiencies, and indicates cooperative binding. Previous results have suggested that CCR of the tre operon occurs by a mechanism in which the specific regulator, TreR, may be involved independently of the central component, CcpA. The data presented here indicate that the TreR-tre operator interaction is influenced by several effectors. Thus, the presence of trehalose-6-phosphate, as well as glucose-1-phosphate and sodium chloride, inhibits tre operator binding. Glucose-6-phosphate can act as an anti-inducer, which might reflect its additional role in CCR exerted by glucose.
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Lehrstuhl für Mikrobiologie, Institut für Mikrobiologie, Biochemie und Genetik der Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
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D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism; D019281:Dimerization; D004790:Enzyme Induction; D004794:Enzyme Repression; D015964:Gene Expression Regulation, Bacterial; D005958:Glucosephosphates / Q000494:pharmacology; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology; D013403:Sugar Phosphates / Q000494:pharmacology; D014199:Trehalose / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D005958:Glucosephosphates; D011994:Recombinant Proteins; D012097:Repressor Proteins; D013403:Sugar Phosphates; C094584:trehalose repressor protein, bacteria; C082722:trehalose-6-phosphate; D012965:Sodium Chloride; D014199:Trehalose; C031590:glucose-1-phosphate