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 such as Fibrobacter succinogenes subsp. succinogenes S85 arabinoxylan alpha-L-arabinofuranosidase. This glycosyl hydrolase family 43 (GH43) includes mostly enzymes that have been annotated as having beta-1,4-xylosidase (beta-D-xylosidase; xylan 1,4-beta-xylosidase; EC 3.2.1.37) activity. They are part of an array of hemicellulases that are involved in the final breakdown of plant cell-wall whereby they degrade xylan. They hydrolyze beta-1,4 glycosidic bonds between two xylose units in short xylooligosaccharides. 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. This subfamily includes the characterized Clostridium stercorarium F-9 beta-xylosidase Xyl43B. It also includes Humicola insolens AXHd3 (HiAXHd3), a GH43 arabinofuranosidase (EC 3.2.1.55) that hydrolyzes O3-linked arabinose of doubly substituted xylans, a feature of the polysaccharide that is recalcitrant to degradation. It possesses an additional C-terminal beta-sandwich domain such that the interface between the domains comprises a xylan binding cleft that houses the active site pocket. The HiAXHd3 active site is tuned to hydrolyze arabinofuranosyl or xylosyl linkages, and the topology of the distal regions of the substrate binding surface confers specificity. It also includes Fibrobacter succinogenes subsp. succinogenes S85 arabinoxylan alpha-L-arabinofuranosidase (Axh1;Fisuc_1769;FSU_2269), Paenibacillus sp. E18 alpha-L-arabinofuranosidase (Abf43A), Bifidobacterium adolescentis ATCC 15703 double substituted xylan alpha-1,3-L-specific arabinofuranosidase d3 (AXHd3;AXH-d3;BaAXH-d3;BAD_0301;E-AFAM2), and Chrysosporium lucknowense C1 arabinoxylan hydrolase / double substituted xylan alpha-1,3-L-arabinofuranosidase (Abn7;AXHd). 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 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 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.

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, Bifunctional GH43-CE protein [Bacteroides eggerthii],6MLY_B Chain B, Bifunctional GH43-CE protein [Bacteroides eggerthii],6MLY_C Chain C, Bifunctional GH43-CE protein [Bacteroides eggerthii],6MLY_D Chain D, Bifunctional GH43-CE protein [Bacteroides eggerthii]

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

Engineeringthe active site of a GH43 glycoside hydrolase generates a biotechnologically significant enzyme that displays both endo- xylanase and exo-arabinofuranosidase activity [Humicola insolens],3ZXK_B Engineering the active site of a GH43 glycoside hydrolase generates a biotechnologically significant enzyme that displays both endo- xylanase and exo-arabinofuranosidase activity [Humicola insolens]

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

Beta-xylosidase OS=Formosa agariphila (strain DSM 15362 / KCTC 12365 / LMG 23005 / KMM 3901 / M-2Alg 35-1) OX=1347342 GN=BN863_22160 PE=1 SV=1

Putative beta-xylosidase OS=Prevotella ruminicola OX=839 PE=3 SV=2

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