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Modeling TEM data of Cellulose Fibrils

Modeling TEM data of Cellulose Fibrils

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Modeling TEM data of Cellulose Fibrils

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  1. Modeling TEM data of Cellulose Fibrils Mike Crowley Peter Ciesielski Bryon Donohoe James Matthews

  2. Mapping TEM to Molecular models National Renewable Energy Laboratory Innovation for Our Energy Future

  3. Twist and kinks in long fibers 3 National Renewable Energy Laboratory Innovation for Our Energy Future

  4. Twist and kinks in long fibers National Renewable Energy Laboratory Innovation for Our Energy Future

  5. Modeling cellulose fiber into TEM Start with cellobiose 36-mer positioned at beginning of fiber path. Choose one shape. Future: we can choose other shapes and sizes. Fix center of mass of this segment at beginning of fiber. 5 National Renewable Energy Laboratory Innovation for Our Energy Future

  6. Modeling cellulose fiber into TEM First cellobiose COM fixed at beginning of fiber, can rotate. Add another cellobiose segment bonded to first. Restrain COM of second segment, run MD to relax structure. Reset restraint along TEM fiber path. Add another segment, ........ 6 National Renewable Energy Laboratory Innovation for Our Energy Future

  7. Modeling cellulose fiber into TEM Final Fiber will be full length. Restrained to TEM fiber path Relaxed to allow twisting and bending in most physically meaningful way Analysis to reveal stresses. Future: relax inside restraining lignin blobs National Renewable Energy Laboratory Innovation for Our Energy Future

  8. Aligning the fiber to the trace

  9. Formal End of presentation • More NREL cellulose work that may be of interest if there is time on following slides. National Renewable Energy Laboratory Innovation for Our Energy Future

  10. Decrystallization as a function of morphology Gregg Beckham • Equilibrated full and partial microfibrils with MD • Four scenarios: yellow chains to be decrystallized Corner Edge Middle Edge 10 12 National Renewable Energy Laboratory Innovation for Our Energy Future

  11. Reaction pathway along ρ with an edge chain • ρ = 0.0 • ρ = 0.5 • ρ = 1.0 15 National Renewable Energy Laboratory Innovation for Our Energy Future

  12. Decrystallization simulations: edge chain 16 National Renewable Energy Laboratory Innovation for Our Energy Future

  13. Free energy results • For equivalent length scale of Cel7A (5 nm): • Corner chain: ~16 kcal/mol • Edge chain: ~27 kcal/mol • Middle chain: ~35 kcal/mol 19 National Renewable Energy Laboratory Innovation for Our Energy Future

  14. Coarse grained modeling of CBM1 Lintao Bu National Renewable Energy Laboratory Innovation for Our Energy Future

  15. CBH I CBM surface location • 0.25 Å resolution grid over 30 Å x 10 Å, full solvation • Cellulose chain in x-direction • Cellobiose length ~ 1 nm Conclusion: The CBM from T. reesei CBH I has stable regions corresponding to the processivity units from the entire CBH I enzyme 1 nm 1 nm National Renewable Energy Laboratory Innovation for Our Energy Future