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Catalytic Site Atlas

CSA LITERATURE entry for 1uok

E.C. nameoligo-1,6-glucosidase
SpeciesBacillus cereus (Bacteria)
E.C. Number (IntEnz)
CSA Homologues of 1uokThere are 159 Homologs
CSA Entries With UniProtID P21332
CSA Entries With EC Number
PDBe Entry 1uok
PDBSum Entry 1uok
MACiE Entry M0285

Literature Report

IntroductionOligo-1,6-glucosidase (dextrin 6-alpha-D-glucanohydrolase) hydrolyses the non-reducing terminal alpha-1,6-glucosidic bonds of isomaltosaccharides, panose, and alpha-limit dextrins. In addition, this enzyme belongs to the family 13 of glycosyl hydrolases, also known as the alpha-amylase family.
MechansimThe alpha-retaining mechanism is a double displacement process, which proceeds in two steps. In the first step, Oligo-1,6-glucosidase cleaves an alpha(1-6) glycosidic bond in its substrate, dextrin or isomaltose, and forms a covalent beta(1-6)-linked glycosyl-enzyme intermediate [3]. In the second step, the resulting glycosyl enzyme is hydrolysed by a water molecule [4]. Two active site amino acids play distinct roles in catalysis. One is the acid/base Glu 255, which protonates the glycosidic oxygen of the scissile bond in the first step, and then deprotonates the attacking water molecule in the second step. The other is the nucleophile, Asp 229, which attacks the sugar, forming the covalent linkage within the intermediate [3],[4].

Catalytic Sites for 1uok

Annotated By Reference To The Literature - Site 4 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription

Literature References

Kizaki H
Polypeptide folding of Bacillus cereus ATCC7064 oligo-1,6-glucosidase revealed by 3.0 A resolution X-ray analysis.
J Biochem 1993 113 646-649
PubMed: 8370659
Watanabe K
The refined crystal structure of Bacillus cereus oligo-1,6-glucosidase at 2.0 A resolution: structural characterization of proline-substitution sites for protein thermostabilization.
J Mol Biol 1997 269 142-153
PubMed: 9193006
Uitdehaag JC
X-ray structures along the reaction pathway of cyclodextrin glycosyltransferase elucidate catalysis in the alpha-amylase family.
Nat Struct Biol 1999 6 432-436
PubMed: 10331869