C. Jourlin et al., THE PERIPLASMIC TORT PROTEIN IS REQUIRED FOR TRIMETHYLAMINE N-OXIDE REDUCTASE GENE INDUCTION IN ESCHERICHIA-COLI, Journal of bacteriology, 178(4), 1996, pp. 1219-1223
Expression of the Escherichia coli torCAD operon, which encodes the tr
imethylamine N-oxide reductase system, is regulated by the presence of
trimethylamine N-oxide through the action of the TorR response regula
tor. We have identified an additional gene, torT, located just downstr
eam from the torR gene, which is necessary for torCAD structural opero
n expression. Insertion within the torT gene dramatically reduced the
expression of a torA'-'lacZ fusion, while presence of the gene in tran
s restored the wild-type phenotype. Overproduction of TorR in a torT s
train resulted in partial constitutive expression of the torA'-'lacZ f
usion, suggesting that TorR acts downstream from TorT. The torT gene c
odes for a 35.7-kDa periplasmic protein which presents some homology w
ith 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.