Glycosyl hydrolase family 43 protein such as Bacteroides thetaiotaomicron VPI-5482 arabinofuranosidase Bt3655. This glycosyl hydrolase family 43 (GH43)-like family includes the characterized arabinofuranosidases (EC 3.2.1.55): Bacteroides thetaiotaomicron VPI-5482 (Bt3655;BT_3655) and Penicillium chrysogenum 31B Abf43B, as well as Bifidobacterium adolescentis ATCC 15703 beta-xylosidase (EC 3.2.1.37) BAD_1527. It belongs to the glycosyl hydrolase clan F (according to carbohydrate-active enzymes database (CAZY)) which includes family 43 (GH43) and 62 (GH62) families. GH43 includes enzymes with beta-xylosidase (EC 3.2.1.37), beta-1,3-xylosidase (EC 3.2.1.-), alpha-L-arabinofuranosidase (EC 3.2.1.55), arabinanase (EC 3.2.1.99), xylanase (EC 3.2.1.8), endo-alpha-L-arabinanases (beta-xylanases) and galactan 1,3-beta-galactosidase (EC 3.2.1.145) activities. GH43 are inverting enzymes (i.e. they invert the stereochemistry of the anomeric carbon atom of the substrate) that have an aspartate as the catalytic general base, a glutamate as the catalytic general acid and another aspartate that is responsible for pKa modulation and orienting the catalytic acid. Many GH43 enzymes display both alpha-L-arabinofuranosidase and beta-D-xylosidase activity using aryl-glycosides as substrates. A common structural feature of GH43 enzymes is a 5-bladed beta-propeller domain 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 family 43 protein; uncharacterized. This glycosyl hydrolase family 43 (GH43)-like subfamily includes uncharacterized enzymes similar to those with beta-1,4-xylosidase (xylan 1,4-beta-xylosidase; EC 3.2.1.37), beta-1,3-xylosidase (EC 3.2.1.-), alpha-L-arabinofuranosidase (EC 3.2.1.55), arabinanase (EC 3.2.1.99), xylanase (EC 3.2.1.8), endo-alpha-L-arabinanase and galactan 1,3-beta-galactosidase (EC 3.2.1.145) activities. These are inverting enzymes (i.e. they invert the stereochemistry of the anomeric carbon atom of the substrate) that have an aspartate as the catalytic general base, a glutamate as the catalytic general acid and another aspartate that is responsible for pKa modulation and orienting the catalytic acid. Many of the enzymes in this family display both alpha-L-arabinofuranosidase and beta-D-xylosidase activity using aryl-glycosides as substrates. A common structural feature of GH43 enzymes is a 5-bladed beta-propeller domain 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 family 43 protein such as Bacillus subtilis subsp. subtilis str. 168 endo-alpha-1,5-L-arabinanase Arb43A. This glycosyl hydrolase family 43 (GH43) subgroup belongs to the glycosyl hydrolase clan F (according to carbohydrate-active enzymes database (CAZY)) which includes family 43 (GH43) and 62 (GH62) families. GH43 are inverting enzymes (i.e. they invert the stereochemistry of the anomeric carbon atom of the substrate) that have an aspartate as the catalytic general base, a glutamate as the catalytic general acid and another aspartate that is responsible for pKa modulation and orienting the catalytic acid. The GH43 ABN enzymes hydrolyze alpha-1,5-L-arabinofuranoside linkages while the ABF enzymes cleave arabinose side chains so that the combined actions of these two enzymes reduce arabinan to L-arabinose and/or arabinooligosaccharides. Many of these enzymes such as the Bacillus subtilis arabinanase Abn2, that hydrolyzes sugar beet arabinan (branched), linear alpha-1,5-L-arabinan and pectin, are different from other arabinases; they are organized into two different domains with a divalent metal cluster close to the catalytic residues to guarantee the correct protonation state of the catalytic residues and consequently the enzyme activity. These arabinan-degrading enzymes are important in the food industry for efficient production of L-arabinose from agricultural waste; L-arabinose is often used as a bioactive sweetener. A common structural feature of GH43 enzymes is a 5-bladed beta-propeller domain 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: GH43, GH62, GH32, GH68, GH117, CH130. Members of the glycosyl hydrolase families 32, 43, 62, 68, 117 and 130 (GH32, GH43, GH62, GH68, GH117, GH130) all possess 5-bladed beta-propeller domains and comprise clans F and J, as classified by the carbohydrate-active enzymes database (CAZY). Clan F consists of families GH43 and GH62. GH43 includes beta-xylosidases (EC 3.2.1.37), beta-xylanases (EC 3.2.1.8), alpha-L-arabinases (EC 3.2.1.99), and alpha-L-arabinofuranosidases (EC 3.2.1.55), using aryl-glycosides as substrates, while family GH62 contains alpha-L-arabinofuranosidases (EC 3.2.1.55) that specifically cleave either alpha-1,2 or alpha-1,3-L-arabinofuranose sidechains from xylans. These are inverting enzymes (i.e. they invert the stereochemistry of the anomeric carbon atom of the substrate) that have an aspartate as the catalytic general base, a glutamate as the catalytic general acid and another aspartate that is responsible for pKa modulation and orienting the catalytic acid. Clan J consists of families GH32 and GH68. GH32 comprises sucrose-6-phosphate hydrolases, invertases (EC 3.2.1.26), inulinases (EC 3.2.1.7), levanases (EC 3.2.1.65), eukaryotic fructosyltransferases, and bacterial fructanotransferases while GH68 consists of frucosyltransferases (FTFs) that include levansucrase (EC 2.4.1.10); beta-fructofuranosidase (EC 3.2.1.26); inulosucrase (EC 2.4.1.9), while GH68 consists of frucosyltransferases (FTFs) that include levansucrase (EC 2.4.1.10); beta-fructofuranosidase (EC 3.2.1.26); inulosucrase (EC 2.4.1.9), all of which use sucrose as their preferential donor substrate. Members of this clan are retaining enzymes (i.e. they retain the configuration at anomeric carbon atom of the substrate) that 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. Structures of all families in the two clans manifest a funnel-shaped active site that comprises two subsites with a single route for access by ligands. Also included in this superfamily are GH117 enzymes that have exo-alpha-1,3-(3,6-anhydro)-l-galactosidase activity, removing terminal non-reducing alpha-1,3-linked 3,6-anhydro-l-galactose residues from their neoagarose substrate, and GH130 that are phosphorylases and hydrolases for beta-mannosides, involved in the bacterial utilization of mannans or N-linked glycans.
Glycoside hydrolase family 130. Members of the glycosyl hydrolase family 130, as classified by the carbohydrate-active enzymes database (CAZY), are phosphorylases and hydrolases for beta-mannosides, and include beta-1,4-mannosylglucose phosphorylase (EC 2.4.1.281), beta-1,4-mannooligosaccharide phosphorylase (EC 2.4.1.319), beta-1,4-mannosyl-N-acetyl-glucosamine phosphorylase (EC 2.4.1.320), beta-1,2-mannobiose phosphorylase (EC 2.4.1.-), beta-1,2-oligomannan phosphorylase (EC 2.4.1.-) and beta-1,2-mannosidase (EC 3.2.1.-). They possess 5-bladed beta-propeller domains similar to families 32, 43, 62, 68, 117 (GH32, GH43, GH62, GH68, GH117). GH130 enzymes are involved in the bacterial utilization of mannans or N-linked glycans. Beta-1,4-mannosylglucose phosphorylase is involved in degradation of beta-1,4-D-mannosyl-N-acetyl-D-glucosamine linkages in the core of N-glycans; it produces alpha-mannose 1-phosphate and glucose from 4-O-beta-D-mannosyl-D-glucose and inorganic phosphate, using a critical catalytic Asp as a proton donor.