alpha-amylase; Reviewed

Alpha amylase catalytic domain found in bacterial 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). This group of CMDs is bacterial. 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.

Glycosidase [Carbohydrate transport and metabolism].

Alpha amylase catalytic domain family. 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; and 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 this 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 maltogenic amylases, cyclodextrin glycosyltransferase, and related proteins. Enzymes such as amylases, cyclomaltodextrinase (CDase), and cyclodextrin glycosyltransferase (CGTase) degrade starch to smaller oligosaccharides by hydrolyzing the alpha-D-(1,4) linkages between glucose residues. In the case of CGTases, an additional cyclization reaction is catalyzed yielding mixtures of cyclic oligosaccharides which are referred to as alpha-, beta-, or gamma-cyclodextrins (CDs), consisting of six, seven, or eight glucose residues, respectively. CGTases are characterized depending on the major product of the cyclization reaction. Besides having similar catalytic site residues, amylases and CGTases contain carbohydrate binding domains that are distant from the active site and are implicated in attaching the enzyme to raw starch granules and in guiding the amylose chain into the active site. The maltogenic alpha-amylase from Bacillus is a five-domain structure, unlike most alpha-amylases, but similar to that of cyclodextrin glycosyltransferase. In addition to the A, B, and C domains, they have a domain D and a starch-binding domain E. Maltogenic amylase is an endo-acting amylase that has activity on cyclodextrins, terminally modified linear maltodextrins, and amylose. 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.

SolutionStrucuture of the CBM25-1 of beta/alpha-amylase from Paenibacillus polymyxa [Paenibacillus polymyxa]

SolutionStrucuture of the CBM25-2 of beta/alpha-amylase from Paenibacillus polymyxa [Paenibacillus polymyxa]

ChainA, ALPHA-AMYLASE G-6 [Halalkalibacterium halodurans C-125],2C3H_A Chain A, ALPHA-AMYLASE G-6 [Halalkalibacterium halodurans],2C3H_B Chain B, ALPHA-AMYLASE G-6 [Halalkalibacterium halodurans],2C3H_C Chain C, ALPHA-AMYLASE G-6 [Halalkalibacterium halodurans],2C3H_D Chain D, ALPHA-AMYLASE G-6 [Halalkalibacterium halodurans],2C3H_E Chain E, ALPHA-AMYLASE G-6 [Halalkalibacterium halodurans],2C3H_F Chain F, ALPHA-AMYLASE G-6 [Halalkalibacterium halodurans],2C3H_G Chain G, ALPHA-AMYLASE G-6 [Halalkalibacterium halodurans],2C3H_H Chain H, ALPHA-AMYLASE G-6 [Halalkalibacterium halodurans]

CrystalStructure of Anoxybacillus Alpha-amylase Provides Insights into a New Glycosyl Hydrolase Subclass [Anoxybacillus ayderensis]

CrystalStructure of Anoxybacillus Alpha-amylase Provides Insights into a New Glycosyl Hydrolase Subclass [Anoxybacillus ayderensis],5A2C_A Crystal Structure of Anoxybacillus Alpha-amylase Provides Insights into a New Glycosyl Hydrolase Subclass [Anoxybacillus ayderensis]

Periplasmic alpha-amylase OS=Escherichia coli (strain K12) OX=83333 GN=malS PE=1 SV=1

Alpha-amylase OS=Niallia circulans OX=1397 GN=igtZ PE=1 SV=1

Beta/alpha-amylase OS=Paenibacillus polymyxa OX=1406 PE=1 SV=1

Beta-amylase OS=Niallia circulans OX=1397 PE=3 SV=1

Cyclomaltodextrin glucanotransferase OS=Bacillus sp. (strain 6.6.3) OX=29335 GN=cgt PE=3 SV=1