(588ce) Integrative Molecular Modeling of Polymeric Composite Materials – a Case-Study with Plant Cell Wall Models.

Plant materials, composed of cell walls, are natural versatile composites that have been and are still being used as a structural, sustainable material for buildings, furniture, tools, textiles etc. The plant cell wall (PCW) is primarily composed of the biopolymers - cellulose, hemicellulose, lignin, and pectin. The material properties of plant biomass emerge from the arrangement and interactions between and the relative abundances of these chemically diverse polymerics in the PCW. One of the major challenges in modeling PCWs and any bulk composite material at the atomistic scale is considering the relative locations of the component polymers in the simulation box. Recent advances in solid-state NMR techniques have been crucial in furthering our understanding of the interactions between the various biopolymers in the PCW and have enabled the quantification of the spatial proximities between the various polymers. This talk will illustrate the use of an integrative modeling approach that incorporates multi-modal experimental data eg: compositional analyses, distinct polymer chemistries, ssNMR proximities, density and moisture content, to build representative atomistic models of the PCW. Our approach starts with a coarse-grained (CG) lattice model used to initially place individual polymers in the simulation box to satisfy the ssNMR proximity constraints. The CG-model is then used as a template to map atomistic representations of each of the polymers in the system to build a fully atomistic model of the PCW. This CG approach results in significant reduction of the computational effort required to build representative detailed atomistic models for molecular dynamics while enhancing our ability to more thoroughly explore the relative polymeric arrangement phase-space in composite materials.