Linked Life Data

10935974

Source:http://linkedlifedata.com/resource/pubmed/id/10935974

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2000-12-7
pubmed:abstractText
The packing of beta-1,4-glucopyranose chains has been modeled to further elaborate the molecular structures of native cellulose microfibrils. A chain pairing procedure was implemented that evaluates the optimal interchain distance and energy for all possible settings of the two chains. Starting with a rigid model of an isolated chain, its interaction with a second chain was studied at various helix-axis translations and mutual rotational orientations while keeping the chains at van der Waals separation. For each setting, the sum of the van der Waals and hydrogen-bonding energy was calculated. No energy minimization was performed during the initial screening, but the energy and interchain distances were mapped to a three-dimensional grid, with evaluation of parallel settings of the cellulose chains. The emergence of several energy minima suggests that parallel chains of cellulose can be paired in a variety of stable orientations. A further analysis considered all possible parallel arrangements occurring between a cellulose chain pair and a further cellulose chain. Among all the low-energy three-chain models, only a few of them yield closely packed three-dimensional arrangements. From these, unit-cell dimensions as well as lattice symmetry were derived; interestingly two of them correspond closely to the observed allomorphs of crystalline native cellulose. The most favorable structural models were then optimized using a minicrystal procedure in conjunction with the MM3 force field. The two best crystal lattice predictions were for a triclinic (P(1)) and a monoclinic (P2(1)) arrangement with unit cell dimensions a = 0.63, b = 0.69, c = 1.036 nm, alpha = 113.0, beta = 121.1, gamma = 76.0 degrees, and a = 0.87, b = 0.75, c = 1.036 nm, gamma = 94.1 degrees, respectively. They correspond closely to the respective lattice symmetry and unit-cell dimensions that have been reported for cellulose Ialpha and cellulose Ibeta allomorphs. The suitability of the modeling protocol is endorsed by the agreement between the predicted and experimental unit-cell dimensions. The results provide pertinent information toward the construction of macromolecular models of microfibrils.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-3525
pubmed:author
pubmed:copyrightInfo
Copyright 2000 John Wiley & Sons, Inc.
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
54
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
342-54
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
A priori crystal structure prediction of native celluloses.
pubmed:affiliation
Ingéniérie Moléculaire, Institut National de la Recherche Agronomique, Rue de la Géraudière, BP 71627, 44316 Nantes Cédex, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't