Structure and chain conformation of a neutral intracellular heteropolysaccharide from mycelium of Paecilomyces cicadae

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• 作者：Chao-yang Wei^a ; ^b ; Wei-qi Li^b ; Shuang-shuang Shao^b ; Liang He^a ; ^{kite006@126.com" class="auth_mail" title="E-mail the corresponding author} ; Junwen Cheng^a ; Sufang Han^a ; Yu Liu^b
• 关键词：Paecilomyces cicadae ; Heteropolysaccharide ; Structural characterization ; Chain conformation ; AFM
• 刊名：Carbohydrate Polymers
• 出版年：2016
• 出版时间：20 January 2016
• 年：2016
• 卷：136
• 期：Complete
• 页码：728-737
• 全文大小：2290 K

文摘

A neutral heteropolysaccharide (PCIPS2) was isolated and purified from mycelium of Paecilomyces cicadae, which was investigated to be mainly composed of d-mannose, l-rhamnose, 3-O-methyl-d-galactose, d-glucose and d-galactose with a molar ratio of 47.9:3.1:6.4:0.9:0.8. It had a backbone of 1,4-linked α-l-Rhap residues and 1,6-linked α-d-Manp residues with branches at O-3 of α-d-Manp residues. Its side chain was comprised of minor terminal β-d-glucose and 1,4-linked α-3-O-Me-d-Galp residues terminated by α-d-galactose. Furthermore, its chain information on the values of weight-average molar mass (M_w), root mean square radius (${〈S^2〉}_z^{1/2}$), hydrodynamic radius (R_h) and intrinsic viscosity ([η]) for PCIPS2 were analyzed to be 3.09 × 10⁴ g/mol, 7.8 nm, 3.6 nm and 8.5 mL/g, respectively. The structural exponent α of 0.57 indicated that PCIPS2 existed as a flexible chain conformation with a coil-like structure in 0.1 M NaNO₃ at 25 °C. In terms of known theory for worm-like chains, the model parameters for PCIPS2 were as following: molar mass per unit contour length (M_L) = 379 nm⁻¹, persistence length (q) = 0.74 nm and hydrodynamic diameter of cylinder (d) = 0.82 nm, which were further evidenced by atomic force microscopy (AFM).