Glycosyl hydrolase family 43 protein such as Bacillus subtilis arabinoxylan arabinofuranohydrolase (XynD;BsAXH-m23;BSU18160). This glycosyl hydrolase family 43 (GH43) subgroup includes characterized Bacillus subtilis arabinoxylan arabinofuranohydrolase (AXH), Caldicellulosiruptor sp. Tok7B.1 beta-1,4-xylanase (EC 3.2.1.8) / alpha-L-arabinosidase (EC 3.2.1.55) XynA, Caldicellulosiruptor sp. Rt69B.1 xylanase C (EC 3.2.1.8) XynC, and Caldicellulosiruptor saccharolyticus beta-xylosidase (EC 3.2.1.37)/ alpha-L-arabinofuranosidase (EC 3.2.1.55) XynF. It belongs to the glycosyl hydrolase clan F (according to carbohydrate-active enzymes database (CAZY)) which includes family 43 (GH43) and 62 (GH62) families. It belongs to the GH43_AXH-like subgroup which includes enzymes that have been annotated as having beta-xylosidase, alpha-L-arabinofuranosidase and arabinoxylan alpha-L-1,3-arabinofuranohydrolase, xylanase (endo-alpha-L-arabinanase) as well as AXH 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. AXHs specifically hydrolyze the glycosidic bond between arabinofuranosyl substituents and xylopyranosyl backbone residues of arabinoxylan. Bacillus subtilis AXH (BsAXH-m2,3) has been shown to cleave arabinose units from O-2- or O-3-mono-substituted xylose residues and superposition of its structure with known structures of the GH43 exo-acting enzymes, beta-xylosidase and alpha-L-arabinanase, each in complex with their substrate, reveals a different orientation of the sugar backbone. Several of these enzymes also contain carbohydrate binding modules (CBMs) that bind cellulose or xylan. 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, includes arabinoxylan arabinofuranohydrolase, beta-xylosidase, endo-1,4-beta-xylanase, and alpha-L-arabinofuranosidase. This subgroup includes Bacillus subtilis arabinoxylan arabinofuranohydrolase (XynD;BsAXH-m23;BSU18160), Butyrivibrio proteoclasticus alpha-L-arabinofuranosidase (Xsa43E;bpr_I2319), Clostridium stercorarium alpha-L-arabinofuranosidase XylA, and metagenomic beta-xylosidase (EC 3.2.1.37) / alpha-L-arabinofuranosidase (EC 3.2.1.55) CoXyl43. It belongs to the glycosyl hydrolase clan F (according to carbohydrate-active enzymes database (CAZY)) which includes family 43 (GH43) and 62 (GH62) families. The GH43_AXH-like subgroup includes enzymes that have been characterized with beta-xylosidase, alpha-L-arabinofuranosidase, endo-alpha-L-arabinanase as well as arabinoxylan arabinofuranohydrolase (AXH) 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. AXHs specifically hydrolyze the glycosidic bond between arabinofuranosyl substituents and xylopyranosyl backbone residues of arabinoxylan. Metagenomic beta-xylosidase/alpha-L-arabinofuranosidase CoXyl43 shows synergy with Trichoderma reesei cellulases and promotes plant biomass saccharification by degrading xylo-oligosaccharides, such as xylobiose and xylotriose, into the monosaccharide xylose. Studies show that the hydrolytic activity of CoXyl43 is stimulated in the presence of calcium. Several of these enzymes also contain carbohydrate binding modules (CBMs) that bind cellulose or xylan. 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, including Butyrivibrio proteoclasticus arabinofuranosidase Xsa43E. This glycosyl hydrolase family 43 (GH43) subgroup belongs to the GH43_AXH-like subgroup which includes enzymes that have been characterized with beta-xylosidase (EC 3.2.1.37), alpha-L-arabinofuranosidase (EC 3.2.1.55), alpha-1,2-L-arabinofuranosidase 43A (arabinan-specific; EC 3.2.1.-), endo-alpha-L-arabinanase as well as arabinoxylan arabinofuranohydrolase (AXH) 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. AXHs specifically hydrolyze the glycosidic bond between arabinofuranosyl substituents and xylopyranosyl backbone residues of arabinoxylan. This subgroup includes Cellvibrio japonicus arabinan-specific alpha-1,2-arabinofuranosidase, CjAbf43A, which confers its specificity by a surface cleft that is complementary to the helical backbone of the polysaccharide, and Butyrivibrio proteoclasticus GH43 enzyme Xsa43E, also an arabinofuranosidase, which has been shown to cleave arabinose side chains from short segments of xylan. Several of these enzymes also contain carbohydrate binding modules (CBMs) that bind cellulose or xylan. 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 Bacteroides thetaiotaomicron VPI-5482 alpha-L-arabinofuranosidases (BT3675;BT_3675) and (BT3662;BT_3662); includes mostly xylanases. This glycosyl hydrolase family 43 (GH43) subgroup includes enzymes that have been annotated as xylan-digesting beta-xylosidase (EC 3.2.1.37) and xylanase (endo-alpha-L-arabinanase, EC 3.2.1.8) activities, as well the Bacteroides thetaiotaomicron VPI-5482 alpha-L-arabinofuranosidases (EC 3.2.1.55) (BT3675;BT_3675) and (BT3662;BT_3662). 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 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 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.

Crystalstructure of a glycoside hydrolase family 43 arabinoxylan arabinofuranohydrolase from Bacillus subtilis. [Bacillus subtilis],3C7F_A Crystal structure of a glycoside hydrolase family 43 arabinoxylan arabinofuranohydrolase from bacillus subtilis in complex with xylotriose. [Bacillus subtilis],3C7H_A Crystal structure of glycoside hydrolase family 43 arabinoxylan arabinofuranohydrolase from Bacillus subtilis in complex with AXOS-4-0.5. [Bacillus subtilis],3C7O_A Crystal structure of a glycoside hydrolase family 43 arabinoxylan arabinofuranohydrolase from Bacillus subtilis in complex with cellotetraose. [Bacillus subtilis]

Crystalstructure of a glycoside hydrolase family 43 arabinoxylan arabinofuranohydrolase from Bacillus subtilis in complex with xylotetraose. [Bacillus subtilis]

ChainA, CARBOHYDRATE BINDING FAMILY 6 [Acetivibrio thermocellus],5A8D_A Chain A, CARBOHYDRATE BINDING FAMILY 6 [Acetivibrio thermocellus]

Xsa43E,a GH43 family enzyme from Butyrivibrio proteoclasticus [Butyrivibrio proteoclasticus B316]

Thestructure and function of an arabinan-specific alpha-1,2-arabinofuranosidase identified from screening the activities of bacterial GH43 glycoside hydrolases [Cellvibrio japonicus Ueda107],3QEE_B The structure and function of an arabinan-specific alpha-1,2-arabinofuranosidase identified from screening the activities of bacterial GH43 glycoside hydrolases [Cellvibrio japonicus Ueda107]

Arabinoxylan arabinofuranohydrolase OS=Paenibacillus polymyxa OX=1406 GN=xynD PE=1 SV=1

Arabinoxylan arabinofuranohydrolase OS=Bacillus subtilis (strain 168) OX=224308 GN=xynD PE=1 SV=2

Xylosidase/arabinosidase OS=Bacteroides ovatus OX=28116 GN=xsa PE=2 SV=1

Beta-xylosidase OS=Prevotella ruminicola OX=839 GN=xynB PE=3 SV=1

Xylosidase/arabinosidase OS=Thermoclostridium stercorarium OX=1510 GN=xylA PE=1 SV=1