The xyloglucan–cellulose assembly at the atomic scale
| Autor: | Karim Mazeau, Jaroslav Hanus |
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| Rok vydání: | 2006 |
| Předmět: |
Models
Molecular Biophysics Models Biological Biochemistry Biomaterials Cell wall chemistry.chemical_compound Molecular dynamics Cell Wall Polymer chemistry Carbohydrate Conformation Side chain Computer Simulation Cellulose Glucans Organic Chemistry General Medicine Plants Cellulose microfibril Xyloglucan Cellulose fiber Chemical engineering chemistry Thermodynamics Xylans Adsorption Microfibril Algorithms |
| Zdroj: | Biopolymers. 82:59-73 |
| ISSN: | 1097-0282 0006-3525 |
| Popis: | The assembly of cell wall components, cellulose and xyloglucan (XG), was investigated at the atomistic scale using molecular dynamics simulations. A molecular model of a cellulose crystal corresponding to the allomorph Ibeta and exhibiting a flexible complex external morphology was employed to mimic the cellulose microfibril. The xyloglucan molecules considered were the three typical basic repeat units, differing only in the size of one of the lateral chain. All the investigated XG fragments adsorb nonspecifically onto cellulose fiber; multiple arrangements are equally probable, and every cellulose surface was capable of binding the short XG molecules. The following structural effects emerged: XG molecules that do not have any long side chains tended to adapt themselves nicely to the topology of the microfibril, forming a flat, outstretched conformation with all the sugar residues interacting with the surface. In contrast, the XG molecules, which have long side chains, were not able to adopt a flat conformation that would enable the interaction of all the XG residues with the surface. In addition to revealing the fundamental atomistic details of the XG adsorption on cellulose, the present calculations give a comprehensive understanding of the way the XG molecules can unsorb from cellulose to create a network that forms the cell wall. Our revisited view of the adsorption features of XG on cellulose microfibrils is consistent with experimental data, and a model of the network is proposed. |
| Databáze: | OpenAIRE |
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