Glycosyl hydrolase family 43 protein; uncharacterized. This glycosyl hydrolase family 43 (GH43)-like subfamily includes uncharacterized enzymes similar to those with beta-1,4-xylosidase (xylan 1,4-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-arabinanase and galactan 1,3-beta-galactosidase (EC 3.2.1.145) 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. Many of the enzymes in this family 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 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 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 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 family 43, beta-D-xylosidases and arabinofuranosidases. This glycosyl hydrolase family 43 (GH43) subgroup 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, including Selenomonas ruminantium beta-D-xylosidase SXA. These 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. It also includes various GH43 family GH43 arabinofuranosidases (EC 3.2.1.55) including Humicola insolens alpha-L-arabinofuranosidase AXHd3, Bacteroides ovatus alpha-L-arabinofuranosidase (BoGH43, XynB), and the bifunctional Phanerochaete chrysosporium xylosidase/arabinofuranosidase (Xyl;PcXyl). 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.

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]

Glycosidehydrolase BT_3662 [Bacteroides thetaiotaomicron VPI-5482],5MSX_B Glycoside hydrolase BT_3662 [Bacteroides thetaiotaomicron VPI-5482],5MSX_C Glycoside hydrolase BT_3662 [Bacteroides thetaiotaomicron VPI-5482]

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

Structureof the family43 beta-Xylosidase from geobacillus stearothermophilus [Geobacillus stearothermophilus],2EXH_B Structure of the family43 beta-Xylosidase from geobacillus stearothermophilus [Geobacillus stearothermophilus],2EXH_C Structure of the family43 beta-Xylosidase from geobacillus stearothermophilus [Geobacillus stearothermophilus],2EXH_D Structure of the family43 beta-Xylosidase from geobacillus stearothermophilus [Geobacillus stearothermophilus]

ChainA, beta-D-xylosidase [Geobacillus stearothermophilus],2EXK_B Chain B, beta-D-xylosidase [Geobacillus stearothermophilus],2EXK_C Chain C, beta-D-xylosidase [Geobacillus stearothermophilus],2EXK_D Chain D, beta-D-xylosidase [Geobacillus stearothermophilus]

Xylan 1,3-beta-xylosidase OS=Vibrio sp. OX=678 GN=xloA PE=1 SV=1