Overview for MACiE Entry M0285
EC Number: 188.8.131.52 (A member of the Hydrolases, Glycosylases, Glycosidases, i.e. enzymes that hydrolyse O- and S-glycosyl compounds)
Enzyme Name: oligo-1,6-glucosidase
Biological Species: Bacillus cereus (Bacteria)
Catalytic Chain UniprotKB Accession Codes:
- P21332 - Oligo-1,6-glucosidase
Representative PDB Code: 1uok - CRYSTAL STRUCTURE OF B. CEREUS OLIGO-1,6-GLUCOSIDASE (Resolution = 2.00 Å).
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Overall Comment: This enzyme can hydrolyse the non-reducing terminal alpha-1,6,glucosidic bonds of isomaltosaccharides, panose and a-limit dextrins, but fails to act on alpha,1,4-glucosidic bonds of maltosaccharides . The anomeric configuration of the substrate is retained, thus the mechanism proceeds via a double displacement process [2,3]. The mechanism here is shown utilising isomaltose.
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Stepwise Description of the Reaction
|Step 1||Asp displaces the terminal sugar in a nucleophilic substitution reaction, forming a covalent bond between the enzyme and substrate.|
|Step 2||Glu255 deprotonates the water, which initiates a nucleophilic attack on the covalently bound sugar, displacing the Asp199.|
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Catalytic Residues Involved
||Location of Function
- H. Kizaki et al. (1993), J. Biochem., 113, 646-649. Polypeptide folding of Bacillus cereus ATCC7064 oligo-1,6-glucosidase revealed by 3.0 A resolution X-ray analysis.
- K. Watanabe et al. (1997), J. Mol. Biol., 269, 142-153. 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. C. M. Uitdehaag et al. (1996), Nat. Struct. Biol., 6, 432-436. X-ray structures along the reaction pathway of cyclodextrin glycosyltransferase elucidate catalysis in the alpha-amylase family.
- K. Watanabe et al. (2001), Biosci. Biotechnol. Biochem., 65, 2058-2064. Identification of catalytic and substrate-binding site residues in Bacillus cereus ATCC7064 oligo-1,6-glucosidase.
Homologue information for M0285 (1uok)
MACiE Homologues (within the PDB)
MACiE Homologues (within UniprotKB/SwissProt)
Entries with at least one Catalytic CATH code in common (different mechanisms):
|M0045 ||cyclomaltodextrin glucanotransferase |
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