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, 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 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 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-like protein such as Clostridium stercorarium alpha-L-arabinofuranosidase XylA. 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. The GH43_XylA-like subgroup includes Clostridium stercorarium alpha-L-arabinofuranosidase XylA, and enzymes that have been annotated as having beta-xylosidase (EC 3.2.1.37), alpha-L-arabinofuranosidase (EC 3.2.1.55), endo-alpha-L-arabinanase (EC 3.2.1.-) 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.

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]

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

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

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

Extracellular endo-alpha-(1->5)-L-arabinanase OS=Thermotoga petrophila (strain ATCC BAA-488 / DSM 13995 / JCM 10881 / RKU-1) OX=390874 GN=Tpet_0637 PE=1 SV=1

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

Extracellular endo-alpha-(1->5)-L-arabinanase 2 OS=Bacillus subtilis (strain 168) OX=224308 GN=abn2 PE=1 SV=2

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

Extracellular exo-alpha-(1->5)-L-arabinofuranosidase ArbA OS=Cellvibrio japonicus (strain Ueda107) OX=498211 GN=arbA PE=1 SV=1