title: Characterization of TreR, the major regulator of the Escherichia coli trehalose system.
abstract: The pathway of trehalose utilization in Escherichia coli is different at low and high osmolarity. The low osmolarity system takes up trehalose as trehalose 6-phosphate which is hydrolyzed to glucose and glucose 6-phosphate. treB and treC, the genes for the enzymes involved, form an operon that is controlled by TreR (encoded by treR), the repressor of the system, for which trehalose 6-phosphate is the inducer. We have cloned and sequenced treR. The protein contains 315 amino acids with a molecular weight of 34,508. TreR was purified and shown to bind as a dimer trehalose 6-phosphate and trehalose with a Kd of 10 and 280 microM, respectively. The conformations of the protein differ from each other with either one or the other substrate-bound. Protease treatment removed the DNA-binding domain from the intact protein leaving the dimerization domain (a 29-kDa carboxyl-terminal fragment) intact. Nuclease protection experiments revealed a palindromic sequence located directly upstream of the -35 promoter sequence of treB that functions as the operator of the system.
authors.affiliation: Department of Biology, University of Konstanz, 78434 Konstanz, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Horlacher
authors.forename: W
authors.initials: W
authors.lastname: Boos
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005809:Genes, Regulator; D008969:Molecular Sequence Data; D012097:Repressor Proteins / Q000235:genetics*; D016415:Sequence Alignment; D014199:Trehalose / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; C490609:TreR protein, E coli; C094584:trehalose repressor protein, bacteria; D014199:Trehalose