Glycosyl hydrolase family 32, such as the putative glycoside hydrolase Escherichia coli Aec43 (FosGH2). This glycosyl hydrolase family 32 (GH32) subgroup includes Escherichia coli strain BEN2908 putative glycoside hydrolase Aec43 (FosGH2). GH32 enzymes cleave sucrose into fructose and glucose via beta-fructofuranosidase activity, producing invert sugar that is a mixture of dextrorotatory D-glucose and levorotatory D-fructose, thus named invertase (EC 3.2.1.26). GH32 family also contains other fructofuranosidases such as inulinase (EC 3.2.1.7), exo-inulinase (EC 3.2.1.80), levanase (EC 3.2.1.65), and transfructosidases such sucrose:sucrose 1-fructosyltransferase (EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (EC 2.4.1.100), sucrose:fructan 6-fructosyltransferase (EC 2.4.1.10), fructan:fructan 6G-fructosyltransferase (EC 2.4.1.243) and levan fructosyltransferases (EC 2.4.1.-). These retaining enzymes (i.e. they retain the configuration at anomeric carbon atom of the substrate) catalyze hydrolysis in two steps involving a covalent glycosyl enzyme intermediate: an aspartate located close to the N-terminus acts as the catalytic nucleophile and a glutamate acts as the general acid/base; a conserved aspartate residue in the Arg-Asp-Pro (RDP) motif stabilizes the transition state. These enzymes are predicted to display a 5-fold beta-propeller fold as found for GH43 and CH68. The breakdown of sucrose is widely used as a carbon or energy source by bacteria, fungi, and plants. Invertase is used commercially in the confectionery industry, since fructose has a sweeter taste than sucrose and a lower tendency to crystallize.

Domain of unknown function (DUF4975). This family consists of uncharacterized proteins around 500 residues in length and is mainly found in various Bacteroides species. Several proteins in this family are annotated as Glycosyl hydrolases, but the function of this protein is unknown.

Glycosyl hydrolase family 32, beta-fructosidases. Glycosyl hydrolase family GH32 cleaves sucrose into fructose and glucose via beta-fructofuranosidase activity, producing invert sugar that is a mixture of dextrorotatory D-glucose and levorotatory D-fructose, thus named invertase (EC 3.2.1.26). This family also contains other fructofuranosidases such as inulinase (EC 3.2.1.7), exo-inulinase (EC 3.2.1.80), levanase (EC 3.2.1.65), and transfructosidases such sucrose:sucrose 1-fructosyltransferase (EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (EC 2.4.1.100), sucrose:fructan 6-fructosyltransferase (EC 2.4.1.10), fructan:fructan 6G-fructosyltransferase (EC 2.4.1.243) and levan fructosyltransferases (EC 2.4.1.-). These retaining enzymes (i.e. they retain the configuration at anomeric carbon atom of the substrate) catalyze hydrolysis in two steps involving a covalent glycosyl enzyme intermediate: an aspartate located close to the N-terminus acts as the catalytic nucleophile and a glutamate acts as the general acid/base; a conserved aspartate residue in the Arg-Asp-Pro (RDP) motif stabilizes the transition state. These enzymes are predicted to display a 5-fold beta-propeller fold as found for GH43 and CH68. The breakdown of sucrose is widely used as a carbon or energy source by bacteria, fungi, and plants. Invertase is used commercially in the confectionery industry, since fructose has a sweeter taste than sucrose and a lower tendency to crystallize. A common structural feature of all these enzymes is a 5-bladed beta-propeller domain, similar to GH43, that contains the catalytic acid and catalytic base. A long V-shaped groove, partially enclosed at one end, forms a single extended substrate-binding surface across the face of the propeller.

Glycosyl hydrolase families 32 and 68, which form the clan GH-J. This glycosyl hydrolase family clan J (according to carbohydrate-active enzymes database (CAZY)) includes family 32 (GH32) and 68 (GH68). GH32 enzymes include invertase (EC 3.2.1.26) and other other fructofuranosidases such as inulinase (EC 3.2.1.7), exo-inulinase (EC 3.2.1.80), levanase (EC 3.2.1.65), and transfructosidases such sucrose:sucrose 1-fructosyltransferase (EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (EC 2.4.1.100), sucrose:fructan 6-fructosyltransferase (EC 2.4.1.10), fructan:fructan 6G-fructosyltransferase (EC 2.4.1.243) and levan fructosyltransferases (EC 2.4.1.-). The GH68 family consists of frucosyltransferases (FTFs) that include levansucrase (EC 2.4.1.10, also known as beta-D-fructofuranosyl transferase), beta-fructofuranosidase (EC 3.2.1.26) and inulosucrase (EC 2.4.1.9). GH32 and GH68 family enzymes are retaining enzymes (i.e. they retain the configuration at anomeric carbon atom of the substrate) and catalyze hydrolysis in two steps involving a covalent glycosyl enzyme intermediate: an aspartate located close to the N-terminus acts as the catalytic nucleophile and a glutamate acts as the general acid/base; a conserved aspartate residue in the Arg-Asp-Pro (RDP) motif stabilizes the transition state. A common structural feature of all these enzymes is a 5-bladed beta-propeller domain, similar to GH43, that contains the catalytic acid and catalytic base. A long V-shaped groove, partially enclosed at one end, forms a single extended substrate-binding surface across the face of the propeller.

Glycosyl hydrolases family 32.

Firstcrystal structure of endo-levanase BT1760 from Bacteroides thetaiotaomicron [Bacteroides thetaiotaomicron]

Endo-levanaseBT1760 mutant E221A from Bacteroides thetaiotaomicron complexed with levantetraose [Bacteroides thetaiotaomicron]

Beta-fructosidase OS=Thermotoga maritima (strain ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826 / MSB8) OX=243274 GN=bfrA PE=1 SV=1

Sucrose-6-phosphate hydrolase OS=Staphylococcus xylosus OX=1288 GN=scrB PE=3 SV=1