PMID:11473129

Citation	Thompson, J, Robrish, SA, Immel, S, Lichtenthaler, FW, Hall, BG and Pikis, A (2001) Metabolism of sucrose and its five linkage-isomeric alpha-D-glucosyl-D-fructoses by Klebsiella pneumoniae. Participation and properties of sucrose-6-phosphate hydrolase and phospho-alpha-glucosidase. J. Biol. Chem. 276:37415-25
Abstract	Klebsiella pneumoniae is presently unique among bacterial species in its ability to metabolize not only sucrose but also its five linkage-isomeric alpha-d-glucosyl-d-fructoses: trehalulose, turanose, maltulose, leucrose, and palatinose. Growth on the isomeric compounds induced a protein of molecular mass approximately 50 kDa that was not present in sucrose-grown cells and which we have identified as an NAD(+) and metal ion-dependent 6-phospho-alpha-glucosidase (AglB). The aglB gene has been cloned and sequenced, and AglB (M(r) = 49,256) has been purified from a high expression system using the chromogenic p-nitrophenyl alpha-glucopyranoside 6-phosphate as substrate. Phospho-alpha-glucosidase catalyzed the hydrolysis of a wide variety of 6-phospho-alpha-glucosides including maltose-6'-phosphate, maltitol-6-phosphate, isomaltose-6'-phosphate, and all five 6'-phosphorylated isomers of sucrose (K(m) approximately 1-5 mm) yet did not hydrolyze sucrose-6-phosphate. By contrast, purified sucrose-6-phosphate hydrolase (M(r) approximately 53,000) hydrolyzed only sucrose-6-phosphate (K(m) approximately 80 microm). Differences in molecular shape and lipophilicity potential between sucrose and its isomers may be important determinants for substrate discrimination by the two phosphoglucosyl hydrolases. Phospho-alpha-glucosidase and sucrose-6-phosphate hydrolase exhibit no significant homology, and by sequence-based alignment, the two enzymes are assigned to Families 4 and 32, respectively, of the glycosyl hydrolase superfamily. The phospho-alpha-glucosidase gene (aglB) lies adjacent to a second gene (aglA), which encodes an EII(CB) component of the phosphoenolpyruvate-dependent sugar:phosphotransferase system. We suggest that the products of the two genes facilitate the phosphorylative translocation and subsequent hydrolysis of the five alpha-d-glucosyl-d-fructoses by K. pneumoniae.
Links	PubMed Online version:10.1074/jbc.M106504200
Keywords	Amino Acid Sequence; Bacterial Proteins/isolation & purification; Base Sequence; Biological Transport; Cloning, Molecular; DNA, Bacterial/analysis; Escherichia coli/enzymology; Fructose/chemistry; Glycoside Hydrolases/metabolism; Hydrolysis; Klebsiella pneumoniae/enzymology; Klebsiella pneumoniae/genetics; Klebsiella pneumoniae/metabolism; Metals/metabolism; Models, Molecular; Molecular Sequence Data; Protein Isoforms/metabolism; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Substrate Specificity; Sucrose/metabolism; alpha-Glucosidases/genetics; alpha-Glucosidases/isolation & purification; alpha-Glucosidases/metabolism; beta-Fructofuranosidase
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
KLEPN:AGLB		GO:0050081: maltose-6'-phosphate glucosidase activity	ECO:0000314:		F		Figure 3 shows the sugar-specific induction of aglB, 6'-phospho-alpha-glucosidase. It was active in all the 6'-phosphorylated isomers of glucose, but not in sucrose.	complete CACAO 4852
KLEPN:AGLB	enables	GO:0050081: maltose-6'-phosphate glucosidase activity	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete

References

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