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trehalose-phosphate phosphatase similar to Escherichia coli trehalose-6-phosphate phosphatase OtsB and Saccharomyces cerevisiae trehalose-phosphatase TPS2 Trehalose biosynthesis in bacteria is known through three pathways - OtsAB, TreYZ and TreS. The OtsAB pathway, also known as the trehalose 6-phosphate synthase (TSP)/ Trehalose-6-phosphate phosphatase (TPP) pathway, is the most common route known to be involved in the stress response of Escherichia coli. It involves converting glucose-6-phosphate and UDP-glucose to form trehalose-6-phosphate (T6P), catalyzed by TPS, the product of the otsA gene, this step is followed by the dephosphorylation of T6P to yield trehalose and inorganic phosphate, catalyzed by a specific TPP, the product of otsB gene. This OtsAB (or TSP/TPP) pathway, is also the most common route known to be involved in the stress response of yeast In Saccharomyces cerevisiae, the corresponding enzymes, TPS1p and TPS2p, form a multimeric synthase complex together with additional regulatory subunits encoded by Tsl1 and Tps3. Trehalose is a common disaccharide accumulated by organisms as a reservation of carbohydrate and in response to unfavorable growth conditions. This family belongs to the haloacid dehalogenase-like (HAD) hydrolases, a large superfamily of diverse enzymes that catalyze carbon or phosphoryl group transfer reactions on a range of substrates, using an active site aspartate in nucleophilic catalysis. Members of this superfamily include 2-L-haloalkanoic acid dehalogenase, azetidine hydrolase, phosphonoacetaldehyde hydrolase, phosphoserine phosphatase, phosphomannomutase, P-type ATPases and many others. HAD hydrolases are found in all three kingdoms of life, and most genomes are predicted to contain multiple HAD-like proteins. Members possess a highly conserved alpha/beta core domain, and many also possess a small cap domain, the fold and function of which is variable. HAD hydrolases are sometimes referred to as belonging to the DDDD superfamily of phosphohydrolases.
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