trehalose synthase. Trehalose synthase interconverts maltose and alpha, alpha-trehalose by transglucosylation. This is one of at least three mechanisms for biosynthesis of trehalose, an important and widespread compatible solute. However, it is not driven by phosphate activation of sugars and its physiological role may tend toward trehalose degradation. This view is accentuated by numerous examples of fusion to a probable maltokinase domain. The sequence region described by this model is found both as the whole of a trehalose synthase and as the N-terminal region of a larger fusion protein that includes trehalose synthase activity. Several of these fused trehalose synthases have a domain homologous to proteins with maltokinase activity from Actinoplanes missouriensis and Streptomyces coelicolor (). [Energy metabolism, Biosynthesis and degradation of polysaccharides]

Alpha amylase catalytic domain found in Trehalose synthetase. Trehalose synthetase (TreS) catalyzes the reversible interconversion of trehalose and maltose. The enzyme catalyzes the reaction in both directions, but the preferred substrate is maltose. Glucose is formed as a by-product of this reaction. It is believed that the catalytic mechanism may involve the cutting of the incoming disaccharide and transfer of a glucose to an enzyme-bound glucose. This enzyme also catalyzes production of a glucosamine disaccharide from maltose and glucosamine. The Alpha-amylase family comprises the largest family of glycoside hydrolases (GH), with the majority of enzymes acting on starch, glycogen, and related oligo- and polysaccharides. These proteins catalyze the transformation of alpha-1,4 and alpha-1,6 glucosidic linkages with retention of the anomeric center. The protein is described as having 3 domains: A, B, C. A is a (beta/alpha) 8-barrel; B is a loop between the beta 3 strand and alpha 3 helix of A; C is the C-terminal extension characterized by a Greek key. The majority of the enzymes have an active site cleft found between domains A and B where a triad of catalytic residues (Asp, Glu and Asp) performs catalysis. Other members of this family have lost the catalytic activity as in the case of the human 4F2hc, or only have 2 residues that serve as the catalytic nucleophile and the acid/base, such as Thermus A4 beta-galactosidase with 2 Glu residues (GH42) and human alpha-galactosidase with 2 Asp residues (GH31). The family members are quite extensive and include: alpha amylase, maltosyltransferase, cyclodextrin glycotransferase, maltogenic amylase, neopullulanase, isoamylase, 1,4-alpha-D-glucan maltotetrahydrolase, 4-alpha-glucotransferase, oligo-1,6-glucosidase, amylosucrase, sucrose phosphorylase, and amylomaltase.

trehalose synthase-fused probable maltokinase. Three pathways for the biosynthesis of trehalose, an osmoprotectant that in some species is also a precursor of certain cell wall glycolipids. Trehalose synthase, TreS, can interconvert maltose and trehalose, but while the equilibrium may favor trehalose, physiological concentrations of trehalose may be much greater than that of maltose and TreS may act largely in its degradation. This model describes a domain found only as a C-terminal fusion to TreS proteins. The most closely related proteins outside this family, Pep2 of Streptomyces coelicolor and Mak1 of Actinoplanes missouriensis, have known maltokinase activity. We suggest this domain acts as a maltokinase and helps drive conversion of trehalose to maltose. [Energy metabolism, Biosynthesis and degradation of polysaccharides]

Alpha amylase catalytic domain found in Sucrose isomerases, oligo-1,6-glucosidase (also called isomaltase; sucrase-isomaltase; alpha-limit dextrinase), dextran glucosidase (also called glucan 1,6-alpha-glucosidase), and related proteins. The sucrose isomerases (SIs) Isomaltulose synthase (EC 5.4.99.11) and Trehalose synthase (EC 5.4.99.16) catalyze the isomerization of sucrose and maltose to produce isomaltulose and trehalulose, respectively. Oligo-1,6-glucosidase (EC 3.2.1.10) hydrolyzes the alpha-1,6-glucosidic linkage of isomaltooligosaccharides, pannose, and dextran. Unlike alpha-1,4-glucosidases (EC 3.2.1.20), it fails to hydrolyze the alpha-1,4-glucosidic bonds of maltosaccharides. Dextran glucosidase (DGase, EC 3.2.1.70) hydrolyzes alpha-1,6-glucosidic linkages at the non-reducing end of panose, isomaltooligosaccharides and dextran to produce alpha-glucose.The common reaction chemistry of the alpha-amylase family enzymes is based on a two-step acid catalytic mechanism that requires two critical carboxylates: one acting as a general acid/base (Glu) and the other as a nucleophile (Asp). Both hydrolysis and transglycosylation proceed via the nucleophilic substitution reaction between the anomeric carbon, C1 and a nucleophile. Both enzymes contain the three catalytic residues (Asp, Glu and Asp) common to the alpha-amylase family as well as two histidine residues which are predicted to be critical to binding the glucose residue adjacent to the scissile bond in the substrates. The Alpha-amylase family comprises the largest family of glycoside hydrolases (GH), with the majority of enzymes acting on starch, glycogen, and related oligo- and polysaccharides. These proteins catalyze the transformation of alpha-1,4 and alpha-1,6 glucosidic linkages with retention of the anomeric center. The protein is described as having 3 domains: A, B, C. A is a (beta/alpha) 8-barrel; B is a loop between the beta 3 strand and alpha 3 helix of A; C is the C-terminal extension characterized by a Greek key. The majority of the enzymes have an active site cleft found between domains A and B where a triad of catalytic residues performs catalysis. Other members of this family have lost the catalytic activity as in the case of the human 4F2hc, or only have 2 residues that serve as the catalytic nucleophile and the acid/base, such as Thermus A4 beta-galactosidase with 2 Glu residues (GH42) and human alpha-galactosidase with 2 Asp residues (GH31). The family members are quite extensive and include: alpha amylase, maltosyltransferase, cyclodextrin glycotransferase, maltogenic amylase, neopullulanase, isoamylase, 1,4-alpha-D-glucan maltotetrahydrolase, 4-alpha-glucotransferase, oligo-1,6-glucosidase, amylosucrase, sucrose phosphorylase, and amylomaltase.

Glycosidase [Carbohydrate transport and metabolism].

Trehalosesynthase from Thermobaculum terrenum [Thermobaculum terrenum ATCC BAA-798]

Structureof trehalose synthase [Thermomonospora curvata DSM 43183],5H2T_B Structure of trehalose synthase [Thermomonospora curvata DSM 43183],5H2T_C Structure of trehalose synthase [Thermomonospora curvata DSM 43183],5H2T_D Structure of trehalose synthase [Thermomonospora curvata DSM 43183],5H2T_E Structure of trehalose synthase [Thermomonospora curvata DSM 43183],5H2T_F Structure of trehalose synthase [Thermomonospora curvata DSM 43183],5H2T_G Structure of trehalose synthase [Thermomonospora curvata DSM 43183],5H2T_H Structure of trehalose synthase [Thermomonospora curvata DSM 43183]

ChainA, Trehalose Synthase/amylase Tres [Mycolicibacterium smegmatis],3ZO9_B Chain B, Trehalose Synthase/amylase Tres [Mycolicibacterium smegmatis],3ZOA_A Chain A, Trehalose Synthase/amylase Tres [Mycolicibacterium smegmatis],3ZOA_B Chain B, Trehalose Synthase/amylase Tres [Mycolicibacterium smegmatis],5JY7_A Complex of Mycobacterium smegmatis trehalose synthase with maltokinase [Mycolicibacterium smegmatis MC2 155],5JY7_B Complex of Mycobacterium smegmatis trehalose synthase with maltokinase [Mycolicibacterium smegmatis MC2 155],5JY7_C Complex of Mycobacterium smegmatis trehalose synthase with maltokinase [Mycolicibacterium smegmatis MC2 155],5JY7_D Complex of Mycobacterium smegmatis trehalose synthase with maltokinase [Mycolicibacterium smegmatis MC2 155],5JY7_E Complex of Mycobacterium smegmatis trehalose synthase with maltokinase [Mycolicibacterium smegmatis MC2 155],5JY7_F Complex of Mycobacterium smegmatis trehalose synthase with maltokinase [Mycolicibacterium smegmatis MC2 155],5JY7_G Complex of Mycobacterium smegmatis trehalose synthase with maltokinase [Mycolicibacterium smegmatis MC2 155],5JY7_H Complex of Mycobacterium smegmatis trehalose synthase with maltokinase [Mycolicibacterium smegmatis MC2 155]

Crystalstructure of M. tuberculosis TreS [Mycobacterium tuberculosis H37Rv],4LXF_B Crystal structure of M. tuberculosis TreS [Mycobacterium tuberculosis H37Rv]

Crystalstructure of trehalose synthase from Deinococcus radiodurans reveals a closed conformation for catalysis of the intramolecular isomerization [Deinococcus radiodurans R1],4TVU_B Crystal structure of trehalose synthase from Deinococcus radiodurans reveals a closed conformation for catalysis of the intramolecular isomerization [Deinococcus radiodurans R1],4TVU_C Crystal structure of trehalose synthase from Deinococcus radiodurans reveals a closed conformation for catalysis of the intramolecular isomerization [Deinococcus radiodurans R1],4TVU_D Crystal structure of trehalose synthase from Deinococcus radiodurans reveals a closed conformation for catalysis of the intramolecular isomerization [Deinococcus radiodurans R1],4TVU_E Crystal structure of trehalose synthase from Deinococcus radiodurans reveals a closed conformation for catalysis of the intramolecular isomerization [Deinococcus radiodurans R1],4TVU_F Crystal structure of trehalose synthase from Deinococcus radiodurans reveals a closed conformation for catalysis of the intramolecular isomerization [Deinococcus radiodurans R1],4TVU_G Crystal structure of trehalose synthase from Deinococcus radiodurans reveals a closed conformation for catalysis of the intramolecular isomerization [Deinococcus radiodurans R1],4TVU_H Crystal structure of trehalose synthase from Deinococcus radiodurans reveals a closed conformation for catalysis of the intramolecular isomerization [Deinococcus radiodurans R1]

Trehalose synthase/amylase TreS OS=Mycolicibacterium smegmatis (strain ATCC 700084 / mc(2)155) OX=246196 GN=treS PE=1 SV=1

Trehalose synthase OS=Pimelobacter sp. (strain R48) OX=51662 GN=treS PE=3 SV=1

Trehalose synthase/amylase TreS OS=Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv) OX=83332 GN=treS PE=1 SV=1

Trehalose synthase/amylase TreS OS=Mycobacterium tuberculosis (strain CDC 1551 / Oshkosh) OX=83331 GN=treS PE=3 SV=1

Trehalose synthase OS=Thermus thermophilus OX=274 GN=treS PE=3 SV=1