Trehalose metabolism in Escherichia coli: stress protection and stress regulation of gene expression
Article first published online: 27 OCT 2006
Volume 8, Issue 2, pages 205–210, April 1993
How to Cite
Strom, A. R. and Kaasen, I. (1993), Trehalose metabolism in Escherichia coli: stress protection and stress regulation of gene expression. Molecular Microbiology, 8: 205–210. doi: 10.1111/j.1365-2958.1993.tb01564.x
- Issue published online: 27 OCT 2006
- Article first published online: 27 OCT 2006
- Received 10 November, 1992; revised and accepted 21 December, 1992.
Endogenously synthesized trehalose is a stress protectant in Escherichia coli. Externally supplied trehalose does not serve as a stress protectant, but it can be utilized as the sole source of carbon and energy. Mutants defective in trehalose synthesis display an impaired osmotic tolerance in minimal growth media without glycine betaine, and an impaired stationary-phaseinduced heat tolerance. Mechanisms for stress protection by trehalose are discussed. The genes for trehalose-6-phosphate synthase (otsA) and anabolic trehalose-6-phosphate phosphatase (otsB) constitute an operon. Their expression is induced both by osmotic stress and by growth into the stationary phase and depend on the sigma factor encoded by rpoS (katF). rpoS is amber-mutated in E. coli K-12 and its DNA sequence varies among K-12 strains. For trehalose catabolism under osmotic stress E. coli depends on the osmoticcally inducible periplasmic trehalase (TreA). In the absence of osmotic stress, trehalose induces the formation of an enzyme IITre (TreB) of the group translocation system, a catabolic trehalose-6-phosphate phosphatase (TreE), and an amylotrehalase (TreC) which converts trehalose to free glucose and a glucose polymer.