| Autor: |
Hisayoshi Kobayashi, Shigeru Ohno, Mitsuru Mimura, Shinichi Kitamura, Hiroshi Isuda, Takao Minami, Hiroshi Urakawa, Yasushi Nakamura, Kanji Kajiwara |
| Rok vydání: |
1997 |
| Předmět: |
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| Zdroj: |
Journal of Molecular Structure: THEOCHEM. :425-435 |
| ISSN: |
0166-1280 |
| DOI: |
10.1016/s0166-1280(96)04959-7 |
| Popis: |
A Monte Carlo method was used to evaluate the chain dimensions and scattering function of (1 → 3)-β-d-glucan in solution. Monte Carlo samples of the glucan chain were generated on the basis of a conformational energy map of the dimeric subunit, i.e. β-laminarabiose. The effect of the excluded volume was introduced into the model by placing hard spheres with a radius Rex at the center of mass of each glucose unit in the chain sequence. The results for the chain length dependence of the quantity 〈S 2 〉 x (〈S 2 〉 is the mean square radius of gyration and x is the degree of polymerization) and the radial distribution of the end-to-end distance have confirmed that the unperturbed (1 → 3)-β-d-glucan chain shows non-Gaussian-type behavior in the region of x 〈S 2 〉 x vs. x data of the curdlan fractions in water-diluted cadoxen, evaluated by light scattering, were found to be simulated by perturbed chains with an excluded volume R ex = 1.0 A . The scattering function was calculated from the ensemble of generated (1 → 3)-β-d-glucan chains as a function of x (x ≤ 40) in the q range up to 1.0 A −1 (q is the scattering vector). The scattering function in the range 0.1 ≤ q ≤ 0.8 A −1 , where the scattering function is sensitive to the local chain conformation, reveals an appreciable oscillation. The calculated scattering function and 〈S2〉 for the Monte Carlo chains with x = 2–7 were in reasonable agreement with preliminary experimental results obtained by small-angle X-ray scattering for the corresponding laminara-oligosaccharides in water. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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