Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
Institute of Food Research, National Agriculture and Food Research Organization, Tsukuba, Japan.
Biosci Biotechnol Biochem. 2023 Sep 21;87(10):1111-1121. doi: 10.1093/bbb/zbad093.
β1-3/1-6 Glucans, known for their diverse structures, comprise a β1-3-linked main chain and β1-6-linked short branches. Laminarin, a β1-3/1-6 glucan extracted from brown seaweed, for instance, includes β1-6 linkages even in the main chain. The diverse structures provide various beneficial functions for the glucan. To investigate the relationship between structure and functionality, and to enable the characterization of β1-3/1-6 glucan-metabolizing enzymes, oligosaccharides containing the exact structures of β1-3/1-6 glucans are required. We synthesized the monomeric units for the synthesis of β1-3/1-6 mixed-linked glucooligosaccharides. 2-(Trimethylsilyl)ethyl 2-O-benzoyl-4,6-O-benzylidene-β-d-glucopyranoside served as an acceptor in the formation of β1-3 linkages. Phenyl 2-O-benzoyl-4,6-O-benzylidene-3-O-(tert-butyldiphenylsilyl)-1-thio-β-d-glucopyranoside and phenyl 2,3-di-O-benzoyl-4,6-di-O-levulinyl-1-thio-β-d-glucopyranoside acted as donors, synthesizing acceptors suitable for the formation of β1-3- and β1-6-linkages, respectively. These were used to synthesize a derivative of Glcβ1-6Glcβ1-3Glcβ1-3Glc, demonstrating that the proposed route can be applied to synthesize the main chain of β-glucan, with the inclusion of both β1-3 and β1-6 linkages.
β1-3/1-6 葡聚糖因其结构多样而备受关注，其主链由β1-3 键连接，短支链由β1-6 键连接。例如，从褐藻中提取的β1-3/1-6 葡聚糖——昆布多糖，其主链中甚至也包含β1-6 键。这种多样的结构为葡聚糖提供了各种有益的功能。为了研究结构与功能之间的关系，并能够对β1-3/1-6 葡聚糖代谢酶进行特征描述，需要含有确切β1-3/1-6 葡聚糖结构的低聚糖。我们合成了用于β1-3/1-6 混合连接葡寡糖合成的单体单元。2-(三甲基硅基)乙基 2-O-苯甲酰基-4,6-O-苯亚甲基-β-d-吡喃葡萄糖苷作为形成β1-3 键的受体。苯 2-O-苯甲酰基-4,6-O-苯亚甲基-3-O-(叔丁基二苯基甲硅烷基)-1-硫代-β-d-吡喃葡萄糖苷和苯 2,3-二-O-苯甲酰基-4,6-二-O-乙酰基-1-硫代-β-d-吡喃葡萄糖苷分别作为供体，合成适合形成β1-3-和β1-6-键的受体。利用这些受体合成了 Glcβ1-6Glcβ1-3Glcβ1-3Glc 的衍生物，证明了所提出的路线可用于合成β-葡聚糖的主链，其中包含β1-3 和β1-6 键。
