CARB 88 |
| Amylose forms regular single stranded V-amylose helices in precipitates and crystals obtained from butanol and aqueous iodine solutions. However, its structure in these solutions remains elusive mainly because amylose does not form molecular solutions in these solvents. We used an atomic force microscope (AFM) to pull single amylose molecules in these poor solvents and probed amylose secondary structure in solution by examining its elasticity. We found that in butanol amylose forms compact helices whose elasticity is controlled by a network of intra-molecular hydrogen bonds. In aqueous iodine solution amylose also forms compact but mechanically weak helices whose elasticity displays a significant hysteresis. Our AFM results are corroborated by Steered Molecular Dynamics (SMD) simulations of amylose in the explicit butanol solvent. AFM-based single molecule force spectroscopy is unique in its capability of determining solution conformations of insoluble biopolymers. Supported by the NSF. |
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General Papers: Analytical Chemistry and Biochemistry of Carbohydrates and Derivatives
8:30 AM-12:30 PM, Thursday, 30 March 2006 Georgia World Congress Center -- B409, Oral
Division of Carbohydrate Chemistry |