Unité Mixte de Recherche Sciences Pour l'Œnologie, Institut Agro, INRAE, Université de Montpellier, Montpellier, France; Lallemand, SAS, 19 rue des Briquetiers, BP 59, 31702 Blagnac, France.
Unité Mixte de Recherche Sciences Pour l'Œnologie, Institut Agro, INRAE, Université de Montpellier, Montpellier, France.
Carbohydr Polym. 2022 Feb 1;277:118758. doi: 10.1016/j.carbpol.2021.118758. Epub 2021 Oct 27.
While they have many properties of interest in enology, the structure-function relationships of mannoproteins and the part played by their polysaccharide moiety are not yet well understood. Mannoproteins (MP) extracted with β-glucanase from a laboratory yeast strain (WT), two of its mutants (Mnn2 with unbranched N-glycosylated chains and Mnn4 without mannosyl-phosphorylation), and an enological strain (Com) were purified and thoroughly characterized. The protein moiety of the four MPs had the same amino acid composition. Glycosyl-linkage and net charge analyses confirmed the expected differences in mutant strain MPs. MP-Com had the highest mannose/glucose ratio followed by MP-WT/MP-Mnn4, and MP-Mnn2 (13.5 > 5.6 ≈ 5.2 > 2.2). The molar mass dependencies of R, R, and [η], determined through HPSEC-MALLS-QELS-Viscosimetry, revealed specific conformational properties of mannoproteins related to their nature of highly branched copolymers with two branching levels. It also clearly showed structural differences between MP-Com, MP-WT/Mnn4, and MP Mnn2, and differences between two populations within the four mannoproteins.
虽然甘露聚糖在酿酒学中有许多引人关注的特性，但甘露聚糖的结构-功能关系及其多糖部分所起的作用尚未得到很好的理解。用β-葡聚糖酶从实验室酵母菌株（WT）、两个突变体（Mnn2 具有无支链的 N-糖基化链和 Mnn4 没有甘露糖磷酸化）和一个酿酒酵母菌株（Com）中提取的甘露聚糖（MP）进行了纯化和彻底表征。这四种 MPs 的蛋白部分具有相同的氨基酸组成。糖基连接和净电荷分析证实了突变株 MPs 的预期差异。MP-Com 具有最高的甘露糖/葡萄糖比，其次是 MP-WT/MP-Mnn4 和 MP-Mnn2（13.5＞5.6≈5.2＞2.2）。通过 HPSEC-MALLS-QELS-Viscosimetry 确定的 R、R 和 [η] 的摩尔质量依赖性，揭示了与甘露聚糖高度支化共聚物的性质相关的特定构象特性，该共聚物具有两个支化水平。它还清楚地显示了 MP-Com、MP-WT/Mnn4 和 MP-Mnn2 之间的结构差异，以及四种甘露聚糖中两个群体之间的差异。
