Alpha amylase catalytic domain found in archaeal and bacterial Alpha-amylases (also called 1,4-alpha-D-glucan-4-glucanohydrolase). AmyA (EC 3.2.1.1) catalyzes the hydrolysis of alpha-(1,4) glycosidic linkages of glycogen, starch, related polysaccharides, and some oligosaccharides. This group includes firmicutes, bacteroidetes, and proteobacteria. 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 bacterial Alpha-amylases (also called 1,4-alpha-D-glucan-4-glucanohydrolase). AmyA (EC 3.2.1.1) catalyzes the hydrolysis of alpha-(1,4) glycosidic linkages of glycogen, starch, related polysaccharides, and some oligosaccharides. This group includes Chloroflexi, Dictyoglomi, and Fusobacteria. 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 cyclomaltodextrinases and related proteins. Cyclomaltodextrinase (CDase; EC3.2.1.54), neopullulanase (NPase; EC 3.2.1.135), and maltogenic amylase (MA; EC 3.2.1.133) catalyze the hydrolysis of alpha-(1,4) glycosidic linkages on a number of substrates including cyclomaltodextrins (CDs), pullulan, and starch. These enzymes hydrolyze CDs and starch to maltose and pullulan to panose by cleavage of alpha-1,4 glycosidic bonds whereas alpha-amylases essentially lack activity on CDs and pullulan. They also catalyze transglycosylation of oligosaccharides to the C3-, C4- or C6-hydroxyl groups of various acceptor sugar molecules. Since these proteins are nearly indistinguishable from each other, they are referred to as cyclomaltodextrinases (CMDs). 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 GlgE-like proteins. GlgE is a (1,4)-a-D-glucan:phosphate a-D-maltosyltransferase, involved in a-glucan biosynthesis in bacteria. It is also an anti-tuberculosis drug target. GlgE isoform I from Streptomyces coelicolor has the same catalytic and very similar kinetic properties to GlgE from Mycobacterium tuberculosis. GlgE from Streptomyces coelicolor forms a homodimer with each subunit comprising five domains (A, B, C, N, and S) and 2 inserts. Domain A is a catalytic alpha-amylase-type domain that along with domain N, which has a beta-sandwich fold and forms the core of the dimer interface, binds cyclodextrins. Domain A, B, and the 2 inserts define a well conserved donor pocket that binds maltose. Cyclodextrins competitively inhibit the binding of maltooligosaccharides to the S. coelicolor enzyme, indicating that the hydrophobic patch overlaps with the acceptor binding site. This is not the case in M. tuberculosis GlgE because cyclodextrins do not inhibit this enzyme, despite acceptor length specificity being conserved. Domain C is hypothesized to help stabilize domain A and could be involved in substrate binding. Domain S is a helix bundle that is inserted within the N domain and it plays a role in the dimer interface and interacts directly with domain B. 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. Alpha amylase is classified as family 13 of the glycosyl hydrolases. The structure is an 8 stranded alpha/beta barrel containing the active site, interrupted by a ~70 a.a. calcium-binding domain protruding between beta strand 3 and alpha helix 3, and a carboxyl-terminal Greek key beta-barrel domain.

Crystalstructure of a noncanonic maltogenic alpha-amylase AmyB from Thermotoga neapolitana [Thermotoga neapolitana],4GKL_B Crystal structure of a noncanonic maltogenic alpha-amylase AmyB from Thermotoga neapolitana [Thermotoga neapolitana]

Crystalstructure of an alpha-amylase from Lactobacillus plantarum [Lactiplantibacillus plantarum],3DHU_B Crystal structure of an alpha-amylase from Lactobacillus plantarum [Lactiplantibacillus plantarum],3DHU_C Crystal structure of an alpha-amylase from Lactobacillus plantarum [Lactiplantibacillus plantarum],3DHU_D Crystal structure of an alpha-amylase from Lactobacillus plantarum [Lactiplantibacillus plantarum]

ScoGlgEI-V279S in complex with a pyrolidene-based ethyl-phosphonate compound [Streptomyces coelicolor A3(2)],5VSJ_B Sco GlgEI-V279S in complex with a pyrolidene-based ethyl-phosphonate compound [Streptomyces coelicolor A3(2)],5VT4_A Sco GlgEI-V279S in complex with a pyrolidene-based methyl-phosphonate compound [Streptomyces coelicolor A3(2)],5VT4_B Sco GlgEI-V279S in complex with a pyrolidene-based methyl-phosphonate compound [Streptomyces coelicolor A3(2)],5VT4_C Sco GlgEI-V279S in complex with a pyrolidene-based methyl-phosphonate compound [Streptomyces coelicolor A3(2)],5VT4_D Sco GlgEI-V279S in complex with a pyrolidene-based methyl-phosphonate compound [Streptomyces coelicolor A3(2)]

ScoGlgEI-V279S in Complex with Reaction Intermediate Azasugar [Streptomyces coelicolor A3(2)],4U2Y_B Sco GlgEI-V279S in Complex with Reaction Intermediate Azasugar [Streptomyces coelicolor A3(2)],4U2Z_A X-ray crystal structure of an Sco GlgEI-V279S/1,2,2-trifluromaltose complex [Streptomyces coelicolor A3(2)],4U2Z_B X-ray crystal structure of an Sco GlgEI-V279S/1,2,2-trifluromaltose complex [Streptomyces coelicolor A3(2)],4U31_A Sco GlgEI-V279S in Complex with maltose-C-phosphonate [Streptomyces coelicolor A3(2)],4U31_B Sco GlgEI-V279S in Complex with maltose-C-phosphonate [Streptomyces coelicolor A3(2)],7MEL_A Chain A, Alpha-1,4-glucan:maltose-1-phosphate maltosyltransferase 1 [Streptomyces coelicolor A3(2)],7MEL_B Chain B, Alpha-1,4-glucan:maltose-1-phosphate maltosyltransferase 1 [Streptomyces coelicolor A3(2)],7MGY_A Chain A, Alpha-1,4-glucan:maltose-1-phosphate maltosyltransferase 1 [Streptomyces coelicolor A3(2)],7MGY_B Chain B, Alpha-1,4-glucan:maltose-1-phosphate maltosyltransferase 1 [Streptomyces coelicolor A3(2)]

Apoform of GlgE isoform 1 from Streptomyces coelicolor [Streptomyces coelicolor],3ZSS_B Apo form of GlgE isoform 1 from Streptomyces coelicolor [Streptomyces coelicolor],3ZSS_C Apo form of GlgE isoform 1 from Streptomyces coelicolor [Streptomyces coelicolor],3ZSS_D Apo form of GlgE isoform 1 from Streptomyces coelicolor [Streptomyces coelicolor],3ZST_A GlgE isoform 1 from Streptomyces coelicolor with alpha-cyclodextrin bound [Streptomyces coelicolor],3ZST_B GlgE isoform 1 from Streptomyces coelicolor with alpha-cyclodextrin bound [Streptomyces coelicolor],3ZT5_A GlgE isoform 1 from Streptomyces coelicolor with maltose bound [Streptomyces coelicolor],3ZT5_B GlgE isoform 1 from Streptomyces coelicolor with maltose bound [Streptomyces coelicolor],3ZT5_C GlgE isoform 1 from Streptomyces coelicolor with maltose bound [Streptomyces coelicolor],3ZT5_D GlgE isoform 1 from Streptomyces coelicolor with maltose bound [Streptomyces coelicolor],3ZT6_A GlgE isoform 1 from Streptomyces coelicolor with alpha-cyclodextrin and maltose bound [Streptomyces coelicolor],3ZT6_B GlgE isoform 1 from Streptomyces coelicolor with alpha-cyclodextrin and maltose bound [Streptomyces coelicolor],3ZT6_C GlgE isoform 1 from Streptomyces coelicolor with alpha-cyclodextrin and maltose bound [Streptomyces coelicolor],3ZT6_D GlgE isoform 1 from Streptomyces coelicolor with alpha-cyclodextrin and maltose bound [Streptomyces coelicolor],3ZT7_A GlgE isoform 1 from Streptomyces coelicolor with beta-cyclodextrin and maltose bound [Streptomyces coelicolor],3ZT7_B GlgE isoform 1 from Streptomyces coelicolor with beta-cyclodextrin and maltose bound [Streptomyces coelicolor],3ZT7_C GlgE isoform 1 from Streptomyces coelicolor with beta-cyclodextrin and maltose bound [Streptomyces coelicolor],3ZT7_D GlgE isoform 1 from Streptomyces coelicolor with beta-cyclodextrin and maltose bound [Streptomyces coelicolor]

Alpha-amylase MalA OS=Haloarcula japonica (strain ATCC 49778 / DSM 6131 / JCM 7785 / NBRC 101032 / NCIMB 13157 / TR-1) OX=1227453 GN=malA PE=1 SV=1

Alpha-1,4-glucan:maltose-1-phosphate maltosyltransferase OS=Salinibacter ruber (strain DSM 13855 / M31) OX=309807 GN=glgE PE=3 SV=1

Alpha-amylase 3 OS=Dictyoglomus thermophilum (strain ATCC 35947 / DSM 3960 / H-6-12) OX=309799 GN=amyC PE=3 SV=2

Alpha-1,4-glucan:maltose-1-phosphate maltosyltransferase 1 OS=Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145) OX=100226 GN=glgE1 PE=1 SV=1

Trehalose-6-phosphate hydrolase OS=Escherichia coli (strain K12) OX=83333 GN=treC PE=1 SV=3