X‐ray crystal structure of anhydrous chitosan at atomic resolution |
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| Authors: | Philip‐Kunio Naito Yu Ogawa Daisuke Sawada Yoshiharu Nishiyama Tadahisa Iwata Masahisa Wada |
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| Affiliation: | 1. Department of Biomaterials Science, Graduate School of Agricultural and Life Science, the University of Tokyo, Tokyo, Japan;2. CNRS, CERMAV, Grenoble, France;3. CERMAV, University Grenoble Alpes, Grenoble, France;4. Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN;5. Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Sakyo‐ku, Kyoto, Japan;6. Department of Plant & Environmental New Resources, College of Life Sciences, Kyung Hee University, Yongin‐si, Gyeonggi‐do, Korea |
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| Abstract: | We determined the crystal structure of anhydrous chitosan at atomic resolution, using X‐ray fiber diffraction data extending to 1.17 Å resolution. The unit cell [a = 8.129(7) Å, b = 8.347(6) Å, c = 10.311(7) Å, space group P212121] of anhydrous chitosan contains two chains having one glucosamine residue in the asymmetric unit with the primary hydroxyl group in the gt conformation, that could be directly located in the Fourier omit map. The molecular arrangement of chitosan is very similar to the corner chains of cellulose II implying similar intermolecular hydrogen bonding between O6 and the amine nitrogen atom, and an intramolecular bifurcated hydrogen bond from O3 to O5 and O6. In addition to the classical hydrogen bonds, all the aliphatic hydrogens were involved in one or two weak hydrogen bonds, mostly helping to stabilize cohesion between antiparallel chains. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 361–368, 2016. |
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| Keywords: | chitosan fiber X‐ray diffraction crystal structure |
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