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Catalytic Site Atlas

CSA LITERATURE entry for 1fob

E.C. namearabinogalactan endo-1,4-beta-galactosidase
SpeciesAspergillus aculeatus ()
E.C. Number (IntEnz) 3.2.1.89
CSA Homologues of 1fobThere are 43 Homologs
CSA Entries With UniProtID P48842
CSA Entries With EC Number 3.2.1.89
PDBe Entry 1fob
PDBSum Entry 1fob
MACiE Entry 1fob

Literature Report

IntroductionAsperfillus aculeatus beta-1,4-Galactanase (AAGAL) is an enzyme involved in pectin degradation. It belongs to the glycoside hydrolase family 53 (GH-53) in clan GH-A. It catalyses the endohydrolysis of beta-1,4-linked galactan and type I arabinogalactan to galactose and galactose oligomers.
Galactan and arabinogalactan are components of pectin which attaches to the C4 position of rhamnose. They forms the side-chains of the 'hairy' region of pectin. Degradation and modification of the galatan and arabinogalactan side chain has many industrial applications, so AAGAL has potential industrial uses.
MechansimGlu136 protonates the glycosidic oxygen while Glu246 acts as a nucleophilic to attack the anomeric carbon to form a covalent enzyme-substrate intermediate. The deprotonated Glu136 then activates a water molecule to hydrolyse the covalent enzyme-substrate intermediate. Arg45 hydrogen bonds with Glu246 to ensure that it is deprotonated even at relatively low pH value to allow it to act as a catalytic nucleophile.
Reaction

Catalytic Sites for 1fob

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
GluA136152macie:sideChainIt protonates the oxygen atom of the glycosidic bond. It deprotonates and activates a water molecule to allow it to hydrolyse the enzyme-substrate complex to regenerate the enzyme.
GluA246262macie:sideChainIt acts as a nucleophile to attack the anomeric carbon of the glycosidic bond to form an enzyme-substrate intermediate.
ArgA4561macie:sideChainIt hydrogen bonds with Glu 246 and alters the pKa of Glu 246 to keep it deprotonated even at relatively low pH value to allow it to act as a nucleophile to attack the anomeric carbon of the glycosidic bond.

Literature References

Notes:
Ryttersgaard C
Aspergillus aculeatus beta-1,4-galactanase: substrate recognition and relations to other glycoside hydrolases in clan GH-A.
Biochemistry 2002 41 15135-15143
PubMed: 12484750
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