Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
52
pubmed:dateCreated
2001-12-25
pubmed:databankReference
pubmed:abstractText
The recycling of photosynthetically fixed carbon by the action of microbial glycoside hydrolases is a key biological process. The consortium of degradative enzymes involved in this process frequently display catalytic modules appended to one or more noncatalytic carbohydrate-binding modules (CBMs). CBMs play a central role in the optimization of the catalytic activity of plant cell wall hydrolases through their binding to specific plant structural polysaccharides. Despite their pivotal role in the biodegradation of plant biomass, the mechanism by which these proteins recognize their target ligands is unclear. This report describes the structure of a xylan-binding CBM (CBM15) in complex with its ligand. This module, derived from Pseudomonas cellulosa xylanase Xyn10C, binds to both soluble xylan and xylooligosaccharides. The three-dimensional crystal structure of CBM15 bound to xylopentaose has been solved by x-ray crystallography to a resolution of 1.6 A. The protein displays a similar beta-jelly roll fold to that observed in many other families of binding-modules. A groove, 20-25 A in length, on the concave surface of one of the beta-sheets presents two tryptophan residues, the faces of which are orientated at approximately 240 degrees to one another. These form-stacking interactions with the n and n+2 sugars of xylopentaose complementing the approximate 3-fold helical structure of this ligand in the binding cleft of CBM15. In four of the five observed binding subsites, the 2' and 3' hydroxyls of the bound ligand are solvent-exposed, providing an explanation for the capacity of this xylan-binding CBM to accommodate the highly decorated xylans found in the plant cell wall.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
49061-5
pubmed:dateRevised
2003-1-3
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Structure of a family 15 carbohydrate-binding module in complex with xylopentaose. Evidence that xylan binds in an approximate 3-fold helical conformation.
pubmed:affiliation
Department of Biological and Nutritional Sciences, The University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, United Kingdom.
pubmed:publicationType
Journal Article