2jke
From Proteopedia
Structure of a family 97 alpha-glucosidase from Bacteroides thetaiotaomicron in complex with deoxynojirimycin
Structural highlights
FunctionSUSB_BACTN Glucoamylase that hydrolyzes alpha-1,4-glucosidic linkages, alpha-1,6-, alpha-1,3- and alpha-1,2-glucosidic linkages during starch degradation.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedEnzymatic cleavage of the glycosidic bond yields products in which the anomeric configuration is either retained or inverted. Each mechanism reflects the dispositions of the enzyme functional groups; a facet of which is essentially conserved in 113 glycoside hydrolase (GH) families. We show that family GH97 has diverged significantly, as it contains both inverting and retaining alpha-glycosidases. This reflects evolution of the active center; a glutamate acts as a general base in inverting members, exemplified by Bacteroides thetaiotaomicron alpha-glucosidase BtGH97a, whereas an aspartate likely acts as a nucleophile in retaining members. The structure of BtGH97a and its complexes with inhibitors, coupled to kinetic analysis of active-site variants, reveals an unusual calcium ion dependence. 1H NMR analysis shows an inversion mechanism for BtGH97a, whereas another GH97 enzyme from B. thetaiotaomicron, BtGH97b, functions as a retaining alpha-galactosidase. Divergence of catalytic mechanism within a glycosidase family provides insight into evolution of carbohydrate metabolism by human gut flora.,Gloster TM, Turkenburg JP, Potts JR, Henrissat B, Davies GJ Chem Biol. 2008 Oct 20;15(10):1058-67. Epub 2008 Oct 9. PMID:18848471[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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