Glycosyl hydrolase family 43 protein such as Geobacillus stearothermophilus endo-alpha-1,5-L-arabinanase AbnA. 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. It includes Geobacillus stearothermophilus T-6 NCIMB 40222 AbnA, Bacillus subtilis subsp. subtilis str. 168 (Abn2;YxiA;J3A;BSU39330) (Arb43B), and Thermotoga petrophila RKU-1 (AbnA;TpABN;Tpet_0637). 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. Many of these enzymes 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.

Beta-xylosidase [Carbohydrate transport and metabolism].

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.

C-terminal of Glycosyl hydrolases family 43. This is the C-terminal of Glycosyl hydrolases family 43. It is around 100 residues in length from various Bacteroides species. The function of this family is unknown.

Glycosyl hydrolase family 43. 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.

Nativestructure of Endo-1,5-alpha-L-arabinanases from Bacillus subtilis [Bacillus subtilis],2X8F_B Native structure of Endo-1,5-alpha-L-arabinanases from Bacillus subtilis [Bacillus subtilis]

CrystalStructure of the Abn2 D171A mutant in complex with arabinotriose [Bacillus subtilis],2X8S_B Crystal Structure of the Abn2 D171A mutant in complex with arabinotriose [Bacillus subtilis]

Theimportance of the Abn2 calcium cluster in the endo-1,5- arabinanase activity from Bacillus subtilis [Bacillus subtilis subsp. subtilis str. 168]

CrystalStructure of the Abn2 H318A mutant [Bacillus subtilis],2X8T_B Crystal Structure of the Abn2 H318A mutant [Bacillus subtilis]

Structureof truncated AbnA (domains 1-3), a GH43 arabinanase from Geobacilllus stearothermophilus, in complex with arabinooctaose [Geobacillus stearothermophilus],5HO9_B Structure of truncated AbnA (domains 1-3), a GH43 arabinanase from Geobacilllus stearothermophilus, in complex with arabinooctaose [Geobacillus stearothermophilus]

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