title: REACH coarse-grained simulation of a cellulose fiber.
abstract: A molecular level understanding of the structure, dynamics and mechanics of cellulose fibers can aid in understanding the recalcitrance of biomass to hydrolysis in cellulosic biofuel production. Here, a residue-scale REACH (Realistic Extension Algorithm via Covariance Hessian) coarse-grained force field was derived from all-atom molecular dynamics (MD) simulations of the crystalline Iβ cellulose fibril. REACH maps the atomistic covariance matrix onto coarse-grained elastic force constants. The REACH force field was found to reproduce the positional fluctuations and low-frequency vibrational spectra from the all-atom model, allowing elastic properties of the cellulose fibril to be characterized using the coarse-grained force field with a speedup of >20 relative to atomistic MD on systems of the same size. The calculated longitudinal/transversal Young's modulus and the velocity of sound are in agreement with experiment. The persistence length of a 36-chain cellulose microcrystal was estimated to be ~380 μm. Finally, the normal-mode analysis with the REACH force field suggests that intrinsic dynamics might facilitate the deconstruction of the cellulose fibril from the hydrophobic surface.
authors.affiliation: UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, P.O. Box 2008 Oak Ridge, Tennessee 37831-6309, USA.
authors.forename: Dennis C
authors.initials: DC
authors.lastname: Glass
authors.forename: Kei
authors.initials: K
authors.lastname: Moritsugu
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Cheng
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: Smith
mesh_terms: D000465:Algorithms; D056804:Biofuels; D018533:Biomass; D002236:Carbohydrate Conformation; D002482:Cellulose / Q000737:chemistry*; D003460:Crystallization; D055119:Elastic Modulus; D006868:Hydrolysis; D057927:Hydrophobic and Hydrophilic Interactions; D056004:Molecular Dynamics Simulation; D013816:Thermodynamics
chemical_list: D056804:Biofuels; D002482:Cellulose