N-terminal catalytic domain of alpha-amylase ( AmyC ) and similar proteins. Alpha-amylases (alpha-1,4-glucan-4-glucanohydrolases, EC 3.2.1.1) play essential roles in alpha-glucan metabolism by catalyzing the hydrolysis of polysaccharides such as amylose starch, and beta-limit dextrin. This subfamily is represented by a novel alpha-amylase (AmyC) encoded by hyperthermophilic organism Thermotoga maritime ORF tm1438, and its prokaryotic homologs. AmyC functions as a homotetramer and shows thermostable amylolytic activity. It is strongly inhibited by acarbose. AmyC is composed of a N-terminal catalytic domain, containing a distorted TIM-barrel structure with a characteristic (beta/alpha)7 fold motif, and two additional less conserved domains. There are other two canonical alpha-amylases encoded from T. maritime that lack the sequence similarity to AmyC, and belong to a different superfamily.

Predicted glycosyl hydrolase, contains GH57 and DUF1957 domains [Carbohydrate transport and metabolism].

N-terminal catalytic domain of Gh57 branching enzyme TK 1436 and similar proteins. The subfamily is represented by a novel branching-enzyme TK1436 of hyperthermophilic archaeon Thermococcus kodakaraensis KOD1. Branching enzymes (BEs, EC 2.4.1.18) play a key role in synthesis of alpha-glucans and they generally are classified into glycoside hydrolase family 13 (GH13). However, TK1436 belongs to the GH57 family. It functions as a monomer and possesses BE activity. TK1436 is composed of a distorted N-terminal (beta/alpha)7-barrel domain and a C-terminal five alpha-helical domain, both of which participate in the formation of the active-site cleft.

phosphatidyl-myo-inositol mannosyltransferase. This family is most closely related to the GT4 family of glycosyltransferases and named after PimA in Propionibacterium freudenreichii, which is involved in the biosynthesis of phosphatidyl-myo-inositol mannosides (PIM) which are early precursors in the biosynthesis of lipomannans (LM) and lipoarabinomannans (LAM), and catalyzes the addition of a mannosyl residue from GDP-D-mannose (GDP-Man) to the position 2 of the carrier lipid phosphatidyl-myo-inositol (PI) to generate a phosphatidyl-myo-inositol bearing an alpha-1,2-linked mannose residue (PIM1). Glycosyltransferases catalyze the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. The acceptor molecule can be a lipid, a protein, a heterocyclic compound, or another carbohydrate residue. This group of glycosyltransferases is most closely related to the previously defined glycosyltransferase family 1 (GT1). The members of this family may transfer UDP, ADP, GDP, or CMP linked sugars. The diverse enzymatic activities among members of this family reflect a wide range of biological functions. The protein structure available for this family has the GTB topology, one of the two protein topologies observed for nucleotide-sugar-dependent glycosyltransferases. GTB proteins have distinct N- and C- terminal domains each containing a typical Rossmann fold. The two domains have high structural homology despite minimal sequence homology. The large cleft that separates the two domains includes the catalytic center and permits a high degree of flexibility. The members of this family are found mainly in certain bacteria and archaea.

Glycosyltransferase involved in cell wall bisynthesis [Cell wall/membrane/envelope biogenesis].

Crystalstructure of the novel alpha-amylase AmyC from Thermotoga maritima [Thermotoga maritima MSB8]

Crystalstructure of GH57-type branching enzyme from hyperthermophilic archaeon Pyrococcus horikoshii [Pyrococcus horikoshii OT3],5WU7_B Crystal structure of GH57-type branching enzyme from hyperthermophilic archaeon Pyrococcus horikoshii [Pyrococcus horikoshii OT3]

ChainA, alpha-amylase, GH57 family [Thermococcus kodakarensis],3N92_A Chain A, alpha-amylase, GH57 family [Thermococcus kodakarensis],3N98_A Chain A, alpha-amylase, GH57 family [Thermococcus kodakarensis]

Thermusthermophilus family GH57 branching enzyme: crystal structure, mechanism of action and products formed [Thermus thermophilus]

Crystalstructure of TT1467 from Thermus thermophilus HB8 [Thermus thermophilus]

1,4-alpha-glucan branching enzyme TK1436 OS=Thermococcus kodakarensis (strain ATCC BAA-918 / JCM 12380 / KOD1) OX=69014 GN=TK1436 PE=1 SV=1

1,4-alpha-glucan branching enzyme TTHA1902 OS=Thermus thermophilus (strain ATCC 27634 / DSM 579 / HB8) OX=300852 GN=TTHA1902 PE=1 SV=1

Glycogen synthase OS=Mycobacterium tuberculosis (strain CDC 1551 / Oshkosh) OX=83331 GN=MT3116 PE=3 SV=1

Glycogen synthase OS=Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv) OX=83332 GN=Rv3032 PE=1 SV=1

Uncharacterized glycosyltransferase MJ1607 OS=Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) OX=243232 GN=MJ1607 PE=3 SV=1