Characterization of TreR, the Major Regulator of the Escherichia coli Trehalose System

• Published in: The Journal of biological chemistry 1997-05, Vol.272 (20), p.13026-13032
• Main Authors: Horlacher, R, Boos, W
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacterial Proteins - genetics; Base Sequence; Cloning, Molecular; Escherichia coli; Escherichia coli - genetics; Escherichia coli Proteins; Gene Expression Regulation, Bacterial; Genes, Bacterial; Genes, Regulator; Molecular Sequence Data; Repressor Proteins - genetics; Sequence Alignment; Trehalose - genetics
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.272.20.13026

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 K d of 10 and 280 μ m , 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.