Subsystem: Trehalose Biosynthesis
This subsystem's description is:
Trehalose is a disaccharide consisting of two subunits of glucose bound by an alpha:1-1
linkage (alpha-D-glucopyranosil alpha-D-glucopyranoside.
Trehalose biosynthesis ability is present in eubacteria, archaea, plants, fungi
and animals. In bacteria there are five different biosynthetic routes, whereas in
fungi, plants and animals there is only one.
There are at least five biosynthetic pathways known for trehalose.
Interestingly, several eubacterial species have multiple pathways, while eukaryotes
have only the TPS/TPP pathway. Vertebrates have lost the capacity to synthesise trehalose
but can break it down to glucose with trehalase.
Eubacteria was the only group where the five pathways were found although not all
together in a single species, most of them having from two to four pathways. The
presence of several biosynthetic pathways in the same organism may be due to the
strict requirement to accumulate trehalose under changeable environmental conditions,
which could limit substrate availability for each pathway. A number of eubacterial
species have multiple copies of some of these pathways. For example, Mesorhizobium
loti, Mycobacterium tuberculosis, Ralstonia solanacearum and Xanthomonas campestris
have two TPS genes, while Thermoanaerobacter tengcongensis has two genes for trehalose
phosphorylase (treP). Phylogenetic analyses suggest that paralogous TPS genes are
the product of lateral gene transfer events instead of recent gene duplications.
The TS pathway might be exclusive to eubacteria, while TreT was only observed in
Archaea and Thermotoga maritima, a thermophilic eubacteria which inherited a substantial
part of its genome from Archaea by lateral gene transfer. In fungi, plants and invertebrates
only the TPS/TPP pathway is present; no homologues to other trehalose biosynthetic
genes were found.
1.1 – The most conserved TPS/TPP pathway is present;
1.2 - TS (Trehalose synthase) pathway is present;
1.3 - TreY/TreZ (conversion of maltodextrines to trehalose) pathway;
1.4 - Trehalose phosphorylase (TP) pathway is present;
1.123 – all listed above pathways are present;
1.1x – TPS/TPP pathway is present, and one more is possible
For more information, please check out the description and the additional notes tabs, below
|Literature References||Insights on the evolution of trehalose biosynthesis. Avonce N BMC evolutionary biology 2006 Dec 19||17178000||Biochemical and genetic characterization of the pathways for trehalose metabolism in Propionibacterium freudenreichii, and their role in stress response. Cardoso FS Microbiology (Reading, England) 2007 Jan||17185556|
|Diagram||Functional Roles||Subsystem Spreadsheet||Description||Additional Notes||Scenarios|