Glycoside hydrolase 97. This domain is the catalytic region of the bacterial glycosyl-hydrolase family 97. This central part of the GH97 family protein sequences represents a typical and complete (beta/alpha)8-barrel or catalytic TIM-barrel type domain. The N- and C-terminal parts of the sequences, mainly consisting of beta-strands, form two additional non-catalytic domains. In all known glycosidases with the (beta-alpha)8-barrel fold, the amino acid residues at the active site are located on the C-termini of the beta-strands.

Glycosyl-hydrolase 97 N-terminal. This N-terminal domain of glycosyl-hydrolase-97 contributes part of the active site pocket. It is also important for contact with the catalytic and C-terminal domains of the whole.

Glycosyl-hydrolase 97 C-terminal, oligomerization. Glycosyl-hydrolase-97 is made up of three tightly linked and highly conserved globular domains. The C-terminal domain is found to be necessary for oligomerization of the whole molecule in order to create the active-site pocket and the Ca++-binding site.

Glycoside hydrolases, clan D. This group of glycosyl hydrolase families is comprised of glycosyl hydrolase family 31 (GH31), family 36 (GH36), and family 27 (GH27). These structurally and mechanistically related protein families are retaining enzymes that cleave their substrates via an acid/base-catalyzed, double-displacement mechanism involving a covalent glycosyl-enzyme intermediate. Two aspartic acid residues have been identified as the catalytic nucleophile and the acid/base, respectively. They have a wide range of functions including alpha-glucosidase, alpha-xylosidase, 6-alpha-glucosyltransferase, 3-alpha-isomaltosyltransferase, alpha-N-acetylgalactosaminidase, stachyose synthase, raffinose synthase, and alpha-1,4-glucan lyase.

glycosyl hydrolase family 36 (GH36). GH36 enzymes occur in prokaryotes, eukaryotes, and archaea with a wide range of hydrolytic activities, including alpha-galactosidase, alpha-N-acetylgalactosaminidase, stachyose synthase, and raffinose synthase. All GH36 enzymes cleave a terminal carbohydrate moiety from a substrate that varies considerably in size, depending on the enzyme, and may be either a starch or a glycoprotein. GH36 members are retaining enzymes that cleave their substrates via an acid/base-catalyzed, double-displacement mechanism involving a covalent glycosyl-enzyme intermediate. Two aspartic acid residues have been identified as the catalytic nucleophile and the acid/base, respectively.

Crystalstructure of BT1871 retaining glycosidase [Bacteroides thetaiotaomicron],3A24_B Crystal structure of BT1871 retaining glycosidase [Bacteroides thetaiotaomicron]

Mutant(D415G) GH97 alpha-galactosidase in complex with Gal-Lac [Bacteroides thetaiotaomicron VPI-5482],5E1Q_B Mutant (D415G) GH97 alpha-galactosidase in complex with Gal-Lac [Bacteroides thetaiotaomicron VPI-5482]

AGlycoside Hydrolase Family 97 enzyme R171K variant from Pseudoalteromonas sp. strain K8 [Pseudoalteromonas sp. K8]

AGlycoside Hydrolase Family 97 enzyme from Pseudoalteromonas sp. strain K8 [Pseudoalteromonas sp. K8],5HQA_A A Glycoside Hydrolase Family 97 enzyme in complex with Acarbose from Pseudoalteromonas sp. strain K8 [Pseudoalteromonas sp. K8]

AGlycoside Hydrolase Family 97 enzyme (E480Q) in complex with Panose from Pseudoalteromonas sp. strain K8 [Pseudoalteromonas sp. K8]

Retaining alpha-galactosidase OS=Bacteroides thetaiotaomicron (strain ATCC 29148 / DSM 2079 / JCM 5827 / CCUG 10774 / NCTC 10582 / VPI-5482 / E50) OX=226186 GN=BT_1871 PE=1 SV=1

Glucan 1,4-alpha-glucosidase SusB OS=Bacteroides thetaiotaomicron (strain ATCC 29148 / DSM 2079 / JCM 5827 / CCUG 10774 / NCTC 10582 / VPI-5482 / E50) OX=226186 GN=susB PE=1 SV=1

Probable retaining alpha-galactosidase OS=Streptomyces bingchenggensis (strain BCW-1) OX=749414 GN=SBI_01652 PE=3 SV=1