Structure conversions of cellulose IIII crystal models in solution state: a molecular dynamics study

Abstract

This paper re-examines our previous molecular dynamics (MD) study on cellulose III I crystal models with finite dimensions solvated in explicit water molecules. Eight crystal models, differing in a constituent lattice plane and dimensions, were studied. One calculation allowed for O-H and C-H bond stretching, and had a small time step of 0.5 fs. The other calculation adopted non-scaling factors of the 1-4 non-bonded interactions. As in our previous study, in the former MD calculations, six of the eight crystal models exhibited structure conversion with cooperative chain slippages generated by a progressive fiber bend. This converted the initial nonstaggered chain packing of cellulose III I into a near one-quarter staggering and gave the crystal model a triclinic-like configuration. In contrast, in the non-1-4 scaling MD calculations, all of the eight crystal models retained the initial cellulose III I crystal structure. Another series of non-1-4 scaling MD calculations were performed for the four crystal models containing chains with a degree of polymerization (DP) of 40 at 370 K, which simulated hot water treatment to convert cellulose III I to Ib. Some of the hydroxymethyl groups irreversibly rotated from gt into tg conformation. This accompanied exchange of the intrasheet hydrogen bonding scheme along the (1 -1 0) lattice plane from O2-O6 to O3-O6. The original corrugated (1 -1 0) chain sheet was partly converted into a cellulose I-like flat chain sheet.

Combining Computational Chemistry and Crystallography for a Better Understanding of the Structure of Cellulose

“…181 Modern determinations of crystal structure 10,11,13 with synchrotron X-ray and neutron diffraction data allow more confidence in the structural details of the various polymorphs. 185 A particularly intriguing use of modern crystal modeling has been the study of enzyme interactions with crystals of cellulose. The models take two forms.…”

Diffraction from nonperiodic models of cellulose crystals

“…Ideally, a molecular dynamics (MD) simulation would reproduce the thermal motion of the atoms and give representative arrangements to the surface molecules and thermal disorder inside the crystals. Various MD studies (Heiner et al 1995;Hardy and Sarko 1996;Kroon-Batenburg and Kroon 1997;Baker et al 2000;Mazeau and Heux 2003;Yui et al 2010), have been reported (see Bergenstråhle et al (2007) and Bellesia et al (2010) for more thorough reviews) but the behavior of model cellulose crystals is quite force-field dependent. Each force field is rationalized and justified based on fits to experimental properties and/or quantum mechanics calculations, and should in principle predict the correct behavior of a molecule.…”

Revealing the Interaction Mechanism Stabilizing Crystalline Cellulose Iβ by Molecular Dynamics Simulations

“…Molecular dynamics simulation has been identified as an excellent tool to understand the structure and interactions of crystalline cellulose in molecular level. Molecular dynamics simulation has been used to understand the hydrogen-bonding interactions of cellulose in some researches [1][2][4][5]. The simulation results are in good accordance with experimental results.…”

“…It is widely used in industry sectors such as textile material, food processing, medical materials, paper and so on. Much effort has focused on investigation of natural crystalline cellulose and synthetic crystalline cellulose during the past few years [1][2][3][4][5]. As for cellulose crystal structures, it has been known that it has several different conformations from I to IV.…”