Glycogen synthase GlgA and similar proteins. This family is most closely related to the GT5 family of glycosyltransferases. Glycogen synthase (EC:2.4.1.21) catalyzes the formation and elongation of the alpha-1,4-glucose backbone using ADP-glucose, the second and key step of glycogen biosynthesis. This family includes starch synthases of plants, such as DULL1 in Zea mays and glycogen synthases of various organisms.

glycogen synthase GlgA.

glycogen/starch synthase, ADP-glucose type. This family consists of glycogen (or starch) synthases that use ADP-glucose (EC 2.4.1.21), rather than UDP-glucose (EC 2.4.1.11) as in animals, as the glucose donor. This enzyme is found in bacteria and plants. Whether the name given is glycogen synthase or starch synthase depends on context, and therefore on substrate. [Energy metabolism, Biosynthesis and degradation of polysaccharides]

Glycogen synthase [Carbohydrate transport and metabolism].

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.

CrystalStructure of Wild-type E.coli GS in complex with ADP and Glucose(wtGSb) [Escherichia coli],2R4T_A Crystal Structure of Wild-type E.coli GS in Complex with ADP and Glucose(wtGSc) [Escherichia coli],2R4U_A Crystal Structure of Wild-type E.coli GS in complex with ADP and Glucose(wtGSd) [Escherichia coli],3GUH_A Crystal Structure of Wild-type E.coli GS in complex with ADP and DGM [Escherichia coli K-12]

ChainA, Glycogen synthase [Escherichia coli]

ChainA, Glycogen synthase [Escherichia coli],3CX4_A Chain A, Glycogen synthase [Escherichia coli]

Structureof barley starch synthase I in complex with maltooligosaccharide [Hordeum vulgare]

ChainA, Glycogen synthase 1 [Agrobacterium tumefaciens],1RZU_B Chain B, Glycogen synthase 1 [Agrobacterium tumefaciens]

Glycogen synthase OS=Geobacillus thermodenitrificans (strain NG80-2) OX=420246 GN=glgA PE=3 SV=1

Glycogen synthase OS=Geobacillus stearothermophilus OX=1422 GN=glgA PE=3 SV=1

Glycogen synthase OS=Anoxybacillus flavithermus (strain DSM 21510 / WK1) OX=491915 GN=glgA PE=3 SV=1

Glycogen synthase OS=Bacillus licheniformis (strain ATCC 14580 / DSM 13 / JCM 2505 / CCUG 7422 / NBRC 12200 / NCIMB 9375 / NCTC 10341 / NRRL NRS-1264 / Gibson 46) OX=279010 GN=glgA PE=3 SV=1

Glycogen synthase OS=Bacillus cereus (strain ATCC 10987 / NRS 248) OX=222523 GN=glgA PE=3 SV=1