Chair of Marine Chemical Resource Development, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Hokkaido, Japan.
Laboratory of Marine Chemical Resource Development, Faculty of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Hokkaido, Japan.
Mar Drugs. 2020 Mar 20;18(3):174. doi: 10.3390/md18030174.
Red alga dulse possesses a unique xylan, which is composed of a linear β-(1→3)/β-(1→4)-xylosyl linkage. We previously prepared characteristic xylooligosaccharide (DX3, (β-(1→3)-xylosyl-xylobiose)) from dulse. In this study, we evaluated the prebiotic effect of DX3 on enteric bacterium. Although DX3 was utilized by sp. and , Ksp. grew slowly as compared with β-(1→4)-xylotriose (X3) but . grew similar to X3. Therefore, we aimed to find the key DX3 hydrolysis enzymes in . . From bioinformatics analysis, two enzymes from the glycoside hydrolase family 43 (BAD0423: subfamily 12 and BAD0428: subfamily 11) were selected and expressed in . BAD0423 hydrolyzed β-(1→3)-xylosyl linkage in DX3 with the specific activity of 2988 mU/mg producing xylose (X1) and xylobiose (X2), and showed low activity on X2 and X3. BAD0428 showed high activity on X2 and X3 producing X1, and the activity of BAD0428 on DX3 was 1298 mU/mg producing X1. Cooperative hydrolysis of DX3 was found in the combination of BAD0423 and BAD0428 producing X1 as the main product. From enzymatic character, hydrolysis of X3 was completed by one enzyme BAD0428, whereas hydrolysis of DX3 needed more than two enzymes.
红藻杜氏藻含有一种独特的木聚糖，由线性β-(1→3)/β-(1→4)-木糖基键组成。我们之前从杜氏藻中制备了具有特征的木二糖（DX3，（β-(1→3)-木糖基-木二糖））。在这项研究中，我们评估了 DX3 对肠道细菌的益生元作用。尽管 DX3 被 sp. 和 利用，但 比 β-(1→4)-木三糖（X3）生长缓慢，但 与 X3 生长相似。因此，我们旨在找到 在 中关键的 DX3 水解酶。通过生物信息学分析，选择糖苷水解酶家族 43 的两种酶（BAD0423：亚家族 12 和 BAD0428：亚家族 11）并在 中表达。BAD0423 以 2988 mU/mg 的比活性水解 DX3 中的 β-(1→3)-木糖基键，产生木糖（X1）和木二糖（X2），并对 X2 和 X3 的活性较低。BAD0428 对 X2 和 X3 表现出高活性，产生 X1，BAD0428 对 DX3 的活性为 1298 mU/mg，产生 X1。发现 BAD0423 和 BAD0428 的组合对 DX3 具有协同水解作用，主要产物为 X1。从酶学特性来看，X3 的水解由一种酶 BAD0428 完成，而 DX3 的水解需要两种以上的酶。
