1,4-alpha-glucan-branching enzyme

Alpha amylase catalytic domain found in bacterial and eukaryotic branching enzymes. Branching enzymes (BEs) catalyze the formation of alpha-1,6 branch points in either glycogen or starch by cleavage of the alpha-1,4 glucosidic linkage yielding a non-reducing end oligosaccharide chain, and subsequent attachment to the alpha-1,6 position. By increasing the number of non-reducing ends, glycogen is more reactive to synthesis and digestion as well as being more soluble. This group includes bacterial and eukaryotic proteins. 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

alpha-amylase; Provisional

Alpha amylase, C-terminal all-beta 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.

ChainA, Isoform 2 of 1,4-alpha-glucan-branching enzyme, chloroplastic/amyloplastic [Oryza sativa Japonica Group]

Structureof the Starch Branching Enzyme I (BEI) from Oryza sativa L [Oryza sativa Japonica Group]

Structureof the Starch Branching Enzyme I (BEI) complexed with maltopentaose from Oryza sativa L [Oryza sativa Japonica Group],3VU2_B Structure of the Starch Branching Enzyme I (BEI) complexed with maltopentaose from Oryza sativa L [Oryza sativa Japonica Group]

Structureof the Starch Branching Enzyme I (BEI) from Oryza sativa L [Oryza sativa Japonica Group]

Crystalstructure of human glycogen branching enzyme (GBE1) in complex with acarbose [Homo sapiens],5CLT_B Crystal structure of human glycogen branching enzyme (GBE1) in complex with acarbose [Homo sapiens],5CLT_C Crystal structure of human glycogen branching enzyme (GBE1) in complex with acarbose [Homo sapiens],5CLW_A Crystal structure of human glycogen branching enzyme (GBE1) in complex with maltoheptaose [Homo sapiens],5CLW_B Crystal structure of human glycogen branching enzyme (GBE1) in complex with maltoheptaose [Homo sapiens],5CLW_C Crystal structure of human glycogen branching enzyme (GBE1) in complex with maltoheptaose [Homo sapiens]

1,4-alpha-glucan-branching enzyme OS=Solanum tuberosum OX=4113 GN=SBE1 PE=2 SV=2

1,4-alpha-glucan-branching enzyme, chloroplastic/amyloplastic OS=Oryza sativa subsp. japonica OX=39947 GN=SBE1 PE=1 SV=2

1,4-alpha-glucan-branching enzyme 1, chloroplastic/amyloplastic (Fragment) OS=Pisum sativum OX=3888 GN=SBEII PE=1 SV=1

1,4-alpha-glucan-branching enzyme OS=Yarrowia lipolytica (strain CLIB 122 / E 150) OX=284591 GN=GLC3 PE=3 SV=1

1,4-alpha-glucan-branching enzyme OS=Emericella nidulans (strain FGSC A4 / ATCC 38163 / CBS 112.46 / NRRL 194 / M139) OX=227321 GN=be1 PE=2 SV=3