Linked Life Data

17376777

Source:http://linkedlifedata.com/resource/pubmed/id/17376777

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
26
pubmed:dateCreated
2007-6-25
pubmed:abstractText
The plant cell wall is a complex material in which the cellulose microfibrils are embedded within a mesh of other polysaccharides, some of which are loosely termed "hemicellulose." One such hemicellulose is xyloglucan, which displays a beta-1,4-linked d-glucose backbone substituted with xylose, galactose, and occasionally fucose moieties. Both xyloglucan and the enzymes responsible for its modification and degradation are finding increasing prominence, reflecting both the drive for enzymatic biomass conversion, their role in detergent applications, and the utility of modified xyloglucans for cellulose fiber modification. Here we present the enzymatic characterization and three-dimensional structures in ligand-free and xyloglucan-oligosaccharide complexed forms of two distinct xyloglucanases from glycoside hydrolase families GH5 and GH12. The enzymes, Paenibacillus pabuli XG5 and Bacillus licheniformis XG12, both display open active center grooves grafted upon their respective (beta/alpha)(8) and beta-jelly roll folds, in which the side chain decorations of xyloglucan may be accommodated. For the beta-jelly roll enzyme topology of GH12, binding of xylosyl and pendant galactosyl moieties is tolerated, but the enzyme is similarly competent in the degradation of unbranched glucans. In the case of the (beta/alpha)(8) GH5 enzyme, kinetically productive interactions are made with both xylose and galactose substituents, as reflected in both a high specific activity on xyloglucan and the kinetics of a series of aryl glycosides. The differential strategies for the accommodation of the side chains of xyloglucan presumably facilitate the action of these microbial hydrolases in milieus where diverse and differently substituted substrates may be encountered.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
29
pubmed:volume
282
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
19177-89
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Characterization and three-dimensional structures of two distinct bacterial xyloglucanases from families GH5 and GH12.
pubmed:affiliation
York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5YW, United Kingdom.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't