Alpha amylase catalytic domain found in maltooligosyl trehalose synthase (MTSase). Maltooligosyl trehalose synthase (MTSase) domain. MTSase and maltooligosyl trehalose trehalohydrolase (MTHase) work together to produce trehalose. MTSase is responsible for converting the alpha-1,4-glucosidic linkage to an alpha,alpha-1,1-glucosidic linkage at the reducing end of the maltooligosaccharide through an intramolecular transglucosylation reaction, while MTHase hydrolyzes the penultimate alpha-1,4 linkage of the reducing end, resulting in the release of trehalose. 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.

Maltooligosyltrehalose synthase [Carbohydrate transport and metabolism].

malto-oligosyltrehalose synthase.

malto-oligosyltrehalose synthase. This enzyme, formally named (1->4)-alpha-D-glucan 1-alpha-D-glucosylmutase, is the TreY enzyme of the TreYZ pathway of trehalose biosynthesis, an alternative to the OtsAB pathway. Trehalose may be incorporated into more complex compounds but is best known as compatible solute. It is one of the most effective osmoprotectants, and unlike the various betaines does not require nitrogen for its synthesis. [Energy metabolism, Biosynthesis and degradation of polysaccharides]

malto-oligosyltrehalose synthase.

structureof Mutant S44P of maltooligosyltrehalose synthase from Arthrobacter ramosus [Arthrobacter ramosus]

structureof maltooligosyltrehalose synthase from Arthrobacter ramosus [Arthrobacter ramosus]

DSM5389glycosyltrehalose synthase [Saccharolobus shibatae B12],5ZCR_B DSM5389 glycosyltrehalose synthase [Saccharolobus shibatae B12]

CrystalStructure of Maltooligosyl trehalose synthase [Sulfolobus acidocaldarius]

Crystalstructure of sulfolobus tokodaii hypothetical maltooligosyl trehalose synthase [Sulfurisphaera tokodaii str. 7]

Maltooligosyl trehalose synthase OS=Arthrobacter sp. (strain Q36) OX=104027 GN=treY PE=1 SV=1

Putative maltooligosyl trehalose synthase OS=Mycobacterium tuberculosis (strain CDC 1551 / Oshkosh) OX=83331 GN=treY PE=3 SV=1

Putative maltooligosyl trehalose synthase OS=Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv) OX=83332 GN=treY PE=1 SV=1

Neopullulanase 2 OS=Thermoactinomyces vulgaris OX=2026 GN=tvaII PE=1 SV=1

Maltogenic alpha-amylase OS=Bacillus acidopullulyticus OX=28030 PE=3 SV=1