Source:http://linkedlifedata.com/resource/pubmed/id/17970751
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
23
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| pubmed:dateCreated |
2007-11-21
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| pubmed:abstractText |
The specificity of the aglycone-binding site of Escherichia coli alpha-xylosidase (YicI), which belongs to glycoside hydrolase family 31, was characterized by examining the enzyme's transxylosylation-catalyzing property. Acceptor specificity and regioselectivity were investigated using various sugars as acceptor substrates and alpha-xylosyl fluoride as the donor substrate. Comparison of the rate of formation of the glycosyl-enzyme intermediate and the transfer product yield using various acceptor substrates showed that glucose is the best complementary acceptor at the aglycone-binding site. YicI preferred aldopyranosyl sugars with an equatorial 4-OH as the acceptor substrate, such as glucose, mannose, and allose, resulting in transfer products. This observation suggests that 4-OH in the acceptor sugar ring made an essential contribution to transxylosylation catalysis. Fructose was also acceptable in the aglycone-binding site, producing two regioisomer transfer products. The percentage yields of transxylosylation products from glucose, mannose, fructose, and allose were 57, 44, 27, and 21%, respectively. The disaccharide transfer products formed by YicI, alpha-D-Xylp-(1-->6)-D-Manp, alpha-D-Xylp-(1-->6)-D-Fruf, and alpha-d-Xylp-(1-->3)-D-Frup, are novel oligosaccharides that have not been reported previously. In the transxylosylation to cello-oligosaccharides, YicI transferred a xylosyl moiety exclusively to a nonreducing terminal glucose residue by alpha-1,6-xylosidic linkages. Of the transxylosylation products, alpha-d-Xylp-(1-->6)-D-Manp and alpha-d-Xylp-(1-->6)-D-Fruf inhibited intestinal alpha-glucosidases.
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Cellobiose,
http://linkedlifedata.com/resource/pubmed/chemical/Escherichia coli Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Oligosaccharides,
http://linkedlifedata.com/resource/pubmed/chemical/Xylosidases,
http://linkedlifedata.com/resource/pubmed/chemical/YicI protein, E coli,
http://linkedlifedata.com/resource/pubmed/chemical/alpha-Glucosidases
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| pubmed:status |
MEDLINE
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| pubmed:month |
Dec
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| pubmed:issn |
1742-464X
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:volume |
274
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
6074-84
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| pubmed:meshHeading |
pubmed-meshheading:17970751-Animals,
pubmed-meshheading:17970751-Binding Sites,
pubmed-meshheading:17970751-Carbohydrate Sequence,
pubmed-meshheading:17970751-Catalysis,
pubmed-meshheading:17970751-Catalytic Domain,
pubmed-meshheading:17970751-Cellobiose,
pubmed-meshheading:17970751-Escherichia coli,
pubmed-meshheading:17970751-Escherichia coli Proteins,
pubmed-meshheading:17970751-Glycosylation,
pubmed-meshheading:17970751-Hydrogen Bonding,
pubmed-meshheading:17970751-Inhibitory Concentration 50,
pubmed-meshheading:17970751-Intestinal Mucosa,
pubmed-meshheading:17970751-Models, Chemical,
pubmed-meshheading:17970751-Oligosaccharides,
pubmed-meshheading:17970751-Protein Binding,
pubmed-meshheading:17970751-Protein Structure, Tertiary,
pubmed-meshheading:17970751-Rats,
pubmed-meshheading:17970751-Substrate Specificity,
pubmed-meshheading:17970751-Xylosidases,
pubmed-meshheading:17970751-alpha-Glucosidases
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| pubmed:year |
2007
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| pubmed:articleTitle |
Aglycone specificity of Escherichia coli alpha-xylosidase investigated by transxylosylation.
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| pubmed:affiliation |
Division of Applied Bioscience, Hokkaido University, Sapporo, Japan.
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| pubmed:publicationType |
Journal Article
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