251. Structural characterization and conformational properties of a polysaccharide isolated from Dendrobium nobile Lindl.
- Author
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Zhang, Yi, Wang, Hongxin, Guo, Qingbin, Wang, Junqiao, and Cui, Steve W.
- Subjects
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MONOSACCHARIDES , *DENDROBIUM , *MONTE Carlo method , *POLYSACCHARIDES , *NUCLEAR magnetic resonance spectroscopy , *ACETYL group , *GLUCOMANNAN - Abstract
A water-soluble polysaccharide (JCP-40) from Dendrobium nobile Lindl. was extracted and purified. It was demonstrated as a single symmetrical peak based on HPSEC analysis and had an average molecular weight of 67.5 kDa. Combined with monosaccharide composition analysis, methylation analysis, 1D/2D NMR spectroscopy, the structural features of JCP-40 was proposed as follows: the major sugar residues of JCP-40 consisted of →4)-β-ᴅ-Man p -(1→ and →4)-β-ᴅ-Glc p -(1 →. Acetyl groups were found attached to the O- 2 or O- 3 positions on mannosyl residues based on NMR spectrum results. Rotational isomeric state (RIS)-Metropolis Monte Carlo method indicated that repeating unit increased from 30 to 120, the influence of Mw in this range affected chain flexibility. The conformational parameters (derived from R g vs Mw and [η] vs Mw) from HPSEC suggested a random coil conformation for JCP-40. Image 1 • A polysaccharide (JCP-40) was purified from Dendrobium nobile Lindl. • The structure features of JCP-40 were characterized. • JCP-40 was a linear glucomannan with O- acetyl group attached. • Computer modeling was applied for the conformational study of glucomannan from D. nobile Lindl. • RIS-Metropolis Monte Carlo (RMMC) method was applied. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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