The periplasmic TorT protein is required for trimethylamine N-oxide reductase gene induction in Escherichia coli.
Expression of the Escherichia coli torCAD operon, which encodes the trimethylamine N-oxide reductase system, is regulated by the presence of trimethylamine N-oxide through the action of the TorR response regulator. We have identified an additional gene, torT, located just downstream from the torR gene, which is necessary for torCAD structural operon expression. Insertion within the torT gene dramatically reduced the expression of a torA'-'lacZ fusion, while presence of the gene in trans restored the wild-type phenotype. Overproduction of TorR in a torT strain resulted in partial constitutive expression of the torA'-'lacZ fusion, suggesting that TorR acts downstream from TorT. The torT gene codes for a 35.7-kDa periplasmic protein which presents some homology with the periplasmic ribose-binding protein of E. coli. We discuss the possible role of TorT as an inducer-binding protein involved in signal transduction of the tor regulatory pathway.
Jourlin
C
C
Laboratoire de Chimie Bactérienne, Institut de Biologie Structurale et Microbiologie, Centre National de la Recherche Scientifique, Marseille, France.
Simon
G
G
Pommier
J
J
Chippaux
M
M
Méjean
V
V
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics; D002451:Cell Compartmentation; D004790:Enzyme Induction; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D009247:NADH, NADPH Oxidoreductases / Q000096:biosynthesis*; D000587:Oxidoreductases Acting on CH-NH Group Donors; D033902:Periplasmic Binding Proteins; D033903:Periplasmic Proteins; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D015533:Transcriptional Activation
D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D033902:Periplasmic Binding Proteins; D033903:Periplasmic Proteins; C028003:RbsB protein, E coli; C089364:TorR protein, E coli; C098062:TorT protein, E coli; D014157:Transcription Factors; C021567:methylamine dehydrogenase; D000587:Oxidoreductases Acting on CH-NH Group Donors; D009247:NADH, NADPH Oxidoreductases