Association with Imidazole in the Cooperative Order-Disorder Transition in Aqueous Solution of Schizophyllan
Association with Imidazole in the Cooperative Order-Disorder Transition in Aqueous Solution of Schizophyllan
复制标题
裂褶多糖水溶液中与咪唑协同有序-无序转变的关系
DOI：
10.1021/acs.langmuir.1c02838
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发表时间：
2022
期刊：
影响因子：
3.9
通讯作者：
Nakano Motohiro
中科院分区：
文献类型：
--
作者：
Yoshiba Kazuto;Yasuda Yota;Christensen Bjorn E.;Kondo Chisaki;Miyazaki Yuji;Nakano Motohiro
裂褶多糖是一种三螺旋多糖，在水溶液中表现出协同有序-无序转变（CODT）。该转变将在支链侧链和溶剂分子之间形成的有序结构（三螺旋I）转化为无序结构（三螺旋II），而不使三螺旋解离。采用绝热量热法和差示扫描量热法研究了两种不同摩尔质量的叶绿素多糖溶液在不同咪唑/HCl摩尔比的H2O-咪唑混合体系中的CODT行为。转变温度（Tr）和转变焓（ΔHr）与咪唑和咪唑/HCl的摩尔分数密切相关。用线性协同跃迁理论分析了H_2O-咪唑混合物中Trand Δ H_1的组成依赖性，研究了活性化合物对混合物的溶剂稳定作用。理论分析证实，溶液中的咪唑和咪唑鎓离子都与三螺旋的侧链竞争性地相互作用。
Schizophyllan, a triple helical polysaccharide, exhibits cooperative order–disorder transition (CODT) in aqueous solutions. The transition transforms the ordered structure (triple helix I) formed between the branched side chains and solvent molecules into the disordered structure (triple helix II) without dissociation of the triple helix. The CODT behaviors in H2O–imidazole mixtures containing HCl with different molar ratios of imidazole/HCl were investigated by adiabatic calorimetry and differential scanning calorimetry on two schizophyllan solutions with different molar masses. The transition temperature (Tr) and the transition enthalpy (ΔHr) significantly depended on both of the mole fractions of imidazole and imidazole/HCl. The composition dependences ofTrand ΔHrin H2O–imidazole mixtures were analyzed with linear cooperative transition theory for the solvent-stabilizing effect in the mixture with active compounds. Theoretical analyses confirmed that both imidazole and imidazolium ions in the solutions competitively interact with the side chain of the triple helix.