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 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 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 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.

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 Endo-1,4-beta-xylanase (NP_811807.1) from BACTEROIDES THETAIOTAOMICRON VPI-5482 at 1.70 A resolution [Bacteroides thetaiotaomicron VPI-5482],3KST_B Crystal structure of Endo-1,4-beta-xylanase (NP_811807.1) from BACTEROIDES THETAIOTAOMICRON VPI-5482 at 1.70 A resolution [Bacteroides thetaiotaomicron VPI-5482]

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

Crystalstructure of an Endo-1,4-beta-xylanase D (BT_3675) from Bacteroides thetaiotaomicron VPI-5482 at 1.74 A resolution [Bacteroides thetaiotaomicron],3QZ4_B Crystal structure of an Endo-1,4-beta-xylanase D (BT_3675) from Bacteroides thetaiotaomicron VPI-5482 at 1.74 A resolution [Bacteroides thetaiotaomicron]

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

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

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

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

Extracellular exo-alpha-(1->5)-L-arabinofuranosidase OS=Streptomyces avermitilis (strain ATCC 31267 / DSM 46492 / JCM 5070 / NBRC 14893 / NCIMB 12804 / NRRL 8165 / MA-4680) OX=227882 GN=Araf43A PE=1 SV=1

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