Linked Life Data

10844677

Source:http://linkedlifedata.com/resource/pubmed/id/10844677

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2000-8-10
pubmed:abstractText
Thermotoga maritima XynA is an extremely thermostable modular enzyme with five domains (A1-A2-B-C1-C2). Its catalytic domain (-B-) is flanked by duplicated non-catalytic domains. The C-terminal repeated domains represent cellulose-binding domains (CBDs). Xylanase domains related to the N-terminal domains of XynA (A1-A2) are called thermostabilizing domains because their deletion normally leads to increased thermosensitivity of the enzymes. It was found that a glutathione-S-transferase (GST) hybrid protein (GST-A1A2) containing both A-domains of XynA can interact with various soluble xylan preparations and with mixed-linkage beta-1,3/beta-1,4-glucans. GST-A1A2 showed no affinity for insoluble microcrystalline cellulose, whereas, vice versa, GST-C2, which contains the C-terminal CBD of XynA, did not interact with soluble xylan. Another hybrid protein, GST-A2, displayed the same binding properties as GST-A1A2, indicating that A2 alone can also promote xylan binding. The dissociation constants for the binding of xylose, xylobiose, xylotriose, xylotetraose and xylopentaose by GST-A2, as determined at 20 degrees C by fluorescence quench experiments, were 8.1 x 10(-3) M, 2.3 x 10(-4) M, 2.3 x 10(-5) M, 2.5 x 10(-6)M and 1.1 x 10(-6) M respectively. The A-domains of XynA, which are designated as xylan binding domains (XBD), are, from the structural as well as the functional point of view, prototypes of a novel class of binding domains. More than 50 related protein segments with hitherto unknown function were detected in about 30 other multidomain beta-glycanases, among them putative plant (Arabidopsis thaliana) xylanases. It is argued that polysaccharide binding and not thermostabilization is the main function of A-like domains.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
898-912
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:10844677-Binding Sites, pubmed-meshheading:10844677-Cellulose, pubmed-meshheading:10844677-Electrophoresis, Polyacrylamide Gel, pubmed-meshheading:10844677-Endo-1,4-beta Xylanases, pubmed-meshheading:10844677-Enzyme Stability, pubmed-meshheading:10844677-Escherichia coli, pubmed-meshheading:10844677-Gene Expression, pubmed-meshheading:10844677-Glucans, pubmed-meshheading:10844677-Glutathione Transferase, pubmed-meshheading:10844677-Oligosaccharides, pubmed-meshheading:10844677-Polysaccharides, pubmed-meshheading:10844677-Recombinant Fusion Proteins, pubmed-meshheading:10844677-Solubility, pubmed-meshheading:10844677-Substrate Specificity, pubmed-meshheading:10844677-Thermotoga maritima, pubmed-meshheading:10844677-Xylans, pubmed-meshheading:10844677-Xylosidases, pubmed-meshheading:10844677-beta-Glucans
pubmed:year
2000
pubmed:articleTitle
The thermostabilizing domain of the modular xylanase XynA of Thermotoga maritima represents a novel type of binding domain with affinity for soluble xylan and mixed-linkage beta-1,3/beta-1, 4-glucan.
pubmed:affiliation
Institut für Mikrobiologie und Genetik, Georg-August-Universität, Göttingen, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't