Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, Schlossplatz 8, 48143, Münster, Germany.
Sci Rep. 2017 Dec 18;7(1):17692. doi: 10.1038/s41598-017-17950-6.
Some of the most abundant biomolecules on earth are the polysaccharides chitin and chitosan of which especially the oligomeric fractions have been extensively studied regarding their biological activities. However, most of these studies have not been able to assess the activity of a single, defined, partially acetylated chitosan oligosaccharide (paCOS). Instead, they have typically analyzed chemically produced, rather poorly characterized mixtures, at best with a single, defined degree of polymerization (DP) and a known average degree of acetylation (DA), as no pure and well-defined paCOS are currently available. We here present data on the enzymatic production of all 14 possible partially acetylated chitosan tetramers, out of which four were purified (>95%) regarding DP, DA, and pattern of acetylation (PA). We used bacterial, fungal, and viral chitin deacetylases (CDAs), either to partially deacetylate the chitin tetramer; or to partially re-N-acetylate the glucosamine tetramer. Both reactions proceeded with surprisingly strong and enzyme-specific regio-specificity. These pure and fully defined chitosans will allow to investigate the particular influence of DP, DA, and PA on the biological activities of chitosans, improving our basic understanding of their modes of action, e.g. their molecular perception by patter recognition receptors, but also increasing their usefulness in industrial applications.
地球上一些最丰富的生物分子是多糖几丁质和壳聚糖，其中寡糖部分的生物活性已被广泛研究。然而，这些研究大多数未能评估单一、定义明确、部分乙酰化的壳聚糖寡糖（paCOS）的活性。相反，它们通常分析化学合成的、特征较差的混合物，最多只有一个、定义明确的聚合度（DP）和已知的平均乙酰化度（DA），因为目前没有纯的、定义明确的 paCOS。我们在此介绍了酶法生产所有 14 种可能的部分乙酰化壳四聚体的相关数据，其中 4 种在 DP、DA 和乙酰化模式（PA）方面得到了高度纯化（>95%）。我们使用细菌、真菌和病毒几丁质脱乙酰酶（CDAs），对壳四聚体进行部分脱乙酰化；或对氨基葡萄糖四聚体进行部分再 N-乙酰化。这两种反应都表现出令人惊讶的强烈和酶特异性区域特异性。这些纯的、完全定义的壳聚糖将能够研究 DP、DA 和 PA 对壳聚糖生物活性的特定影响，从而提高我们对其作用模式的基本认识，例如它们被模式识别受体的分子感知，同时也提高了它们在工业应用中的有用性。
