Glycosyl hydrolase family 43 protein such as Halothermothrix orenii H 168 alpha-L-arabinofuranosidase (HoAraf43;Hore_20580). This glycosyl hydrolase family 43 (GH43) subgroup includes Halothermothrix orenii H 168 alpha-L-arabinofuranosidase (EC 3.2.1.55) (HoAraf43;Hore_20580). It belongs to the glycosyl hydrolase clan F (according to carbohydrate-active enzymes database (CAZY)) which includes family 43 (GH43) and 62 (GH62) families. This GH43_ HoAraf43-like subgroup includes enzymes that have been annotated as having xylan-digesting beta-xylosidase (EC 3.2.1.37) and xylanase (endo-alpha-L-arabinanase, EC 3.2.1.8) 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 such as endo-alpha-L-arabinanase. This glycosyl hydrolase family 43 (GH43) subgroup includes mostly enzymes with alpha-L-arabinofuranosidase (ABF; EC 3.2.1.55) and endo-alpha-L-arabinanase (ABN; EC 3.2.1.99) 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. 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. 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 hydrolases family 43. The glycosyl hydrolase family 43 contains members that are arabinanases. Arabinanases hydrolyze the alpha-1,5-linked L-arabinofuranoside backbone of plant cell wall arabinans. The structure of arabinanase Arb43A from Cellvibrio japonicus reveals a five-bladed beta-propeller fold. 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 43 and 62 form CAZY clan GH-F. This glycosyl hydrolase clan F (according to carbohydrate-active enzymes database (CAZY)) includes family 43 (GH43) and 62 (GH62). 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. GH62 includes enzymes characterized as arabinofuranosidases (alpha-L-arabinofuranosidases; EC 3.2.1.55) that specifically cleave either alpha-1,2 or alpha-1,3-L-arabinofuranose side chains from xylans. 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 of the enzymes in this family display both alpha-L-arabinofuranosidase and beta-D-xylosidase activity using aryl-glycosides as substrates. GH62 are also predicted to be inverting enzymes. A common structural feature of both, GH43 and GH62 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 proteins such as Lactobacillus brevis alpha-L-arabinofuranosidase LbAraf43 and Geobacillus thermoleovorans GbtXyl43B. This glycosyl hydrolase family 43 (GH43) subgroup includes enzymes with beta-xylosidase (EC 3.2.1.37), alpha-L-arabinofuranosidase (EC 3.2.1.55) and possibly bifunctional xylosidase/arabinofuranosidase activities. In addition to Lactobacillus brevis alpha-L-arabinofuranosidase LbAraf43 and Geobacillus thermoleovorans IT-08 beta-xylosidase / exo-xylanase (GbtXyl43B). It belongs to the glycosyl hydrolase clan F (according to carbohydrate-active enzymes database (CAZY)) which includes family 43 (GH43) and 62 (GH62) familiesGH43 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.

Crystalstructure of a thermostable family-43 glycoside hydrolase [Halothermothrix orenii H 168],4QQS_B Crystal structure of a thermostable family-43 glycoside hydrolase [Halothermothrix orenii H 168]

Crystalstructure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compost microbial metagenome, calcium-free form. [uncultured bacterium],5GLK_B Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compost microbial metagenome, calcium-free form. [uncultured bacterium],5GLL_A Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compostmicrobial metagenome, calcium-bound form [uncultured bacterium],5GLL_B Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compostmicrobial metagenome, calcium-bound form [uncultured bacterium],5GLM_A Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compost microbial metagenome in complex with xylotriose, calcium-free form. [uncultured bacterium],5GLM_B Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compost microbial metagenome in complex with xylotriose, calcium-free form. [uncultured bacterium],5GLN_A Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compostmicrobial metagenome in complex with xylotriose, calcium-bound form [uncultured bacterium],5GLN_B Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compostmicrobial metagenome in complex with xylotriose, calcium-bound form [uncultured bacterium],5GLO_A Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compostmicrobial metagenome in complex with l-arabinose, calcium-free form [uncultured bacterium],5GLO_B Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compostmicrobial metagenome in complex with l-arabinose, calcium-free form [uncultured bacterium],5GLP_A Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compostmicrobial metagenome in complex with l-arabinose, calcium-bound form [uncultured bacterium],5GLP_B Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compostmicrobial metagenome in complex with l-arabinose, calcium-bound form [uncultured bacterium],5GLQ_A Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compostmicrobial metagenome in complex with l-arabinose and xylotriose, calcium-free form [uncultured bacterium],5GLQ_B Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compostmicrobial metagenome in complex with l-arabinose and xylotriose, calcium-free form [uncultured bacterium],5GLR_A Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compostmicrobial metagenome in complex with l-arabinose and xylotriose, calcium-bound form [uncultured bacterium],5GLR_B Crystal structure of CoXyl43, GH43 beta-xylosidase/alpha-arabinofuranosidase from a compostmicrobial metagenome in complex with l-arabinose and xylotriose, calcium-bound form [uncultured bacterium]

ChainA, Beta-xylanase [Bacteroides intestinalis],7ERL_B Chain B, Beta-xylanase [Bacteroides intestinalis]