Alpha amylase catalytic domain found in Amylosucrase. Amylosucrase is a glucosyltransferase that catalyzes the transfer of a D-glucopyranosyl moiety from sucrose onto an acceptor molecule. When the acceptor is another saccharide, only alpha-1,4 linkages are produced. Unlike most amylopolysaccharide synthases, it does not require any alpha-D-glucosyl nucleoside diphosphate substrate. In the presence of glycogen it catalyzes the transfer of a D-glucose moiety onto a glycogen branch, but in its absence, it hydrolyzes sucrose and synthesizes polymers, smaller maltosaccharides, and sucrose isoforms. 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.

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.

Maltogenic Amylase, C-terminal domain. This is the C-terminal domain of Maltogenic amylase, an enzyme that hydrolyzes starch material. Maltogenic amylases are central to carbohydrate metabolism.

ChainA, amylosucrase [Calidithermus timidus DSM 17022],7ESH_B Chain B, amylosucrase [Calidithermus timidus DSM 17022],7ESH_C Chain C, amylosucrase [Calidithermus timidus DSM 17022],7ESH_D Chain D, amylosucrase [Calidithermus timidus DSM 17022]

Crystalstructure of Neisseria polysaccharea amylosucrase mutant efficient for the synthesis of controlled size maltooligosaccharides [Neisseria polysaccharea]

Crystalstructure of Amylosucrase double mutant A289P-F290C from Neisseria polysaccharea [Neisseria polysaccharea]

AmylosucraseFrom Neisseria Polysaccharea [Neisseria polysaccharea],1JG9_A Crystal Structure of Amylosucrase from Neisseria polysaccharea in Complex with D-glucose [Neisseria polysaccharea],1MW1_A Amylosucrase soaked with 14mM sucrose. [Neisseria polysaccharea],1MW2_A Amylosucrase soaked with 100mM sucrose [Neisseria polysaccharea],1MW3_A Amylosucrase soaked with 1M sucrose [Neisseria polysaccharea]

Crystalstructure of Amylosucrase double mutant A289P-F290I from Neisseria polysaccharea. [Neisseria polysaccharea]

Amylosucrase OS=Neisseria polysaccharea OX=489 GN=ams PE=1 SV=1

Amylosucrase OS=Neisseria meningitidis OX=487 GN=ams PE=3 SV=1

Glucosylglycerate phosphorylase OS=Escherichia coli (strain K12) OX=83333 GN=ycjM PE=1 SV=2