Life Science College, Shandong Normal University, Jinan 250014, China.
College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao 266003, China.
Mar Drugs. 2022 Feb 23;20(3):159. doi: 10.3390/md20030159.
Alginate oligosaccharides (AOS) have many biological activities and significant applications in prebiotics, nutritional supplements, and plant growth development. Alginate lyases have unique advantages in the preparation of AOS. However, only a limited number of alginate lyases have been so far reported to have potentials in the preparation of AOS with specific degrees of polymerization. Here, an alginate-degrading strain M9 was isolated from , and five alginate lyases were predicted in its genome. These putative alginate lyases were expressed and their degradation products towards sodium alginate were analyzed. Among them, AlyM2 mainly generated trisaccharides, which accounted for 79.9% in the products. AlyM2 is a PL6 lyase with low sequence identity (≤28.3%) to the characterized alginate lyases and may adopt a distinct catalytic mechanism from the other PL6 alginate lyases based on sequence alignment. AlyM2 is a bifunctional endotype lyase, exhibiting the highest activity at 30 °C, pH 8.0, and 0.5 M NaCl. AlyM2 predominantly produces trisaccharides from homopolymeric M block (PM), homopolymeric G block (PG), or sodium alginate, with a trisaccharide production of 588.4 mg/g from sodium alginate, indicating its promising potential in preparing trisaccharides from these polysaccharides.
海藻酸盐寡糖（AOS）具有许多生物活性，在益生元、营养补充剂和植物生长发育方面有重要的应用。在 AOS 的制备中，海藻酸盐裂解酶具有独特的优势。然而，迄今为止，只有少数几种海藻酸盐裂解酶被报道具有制备具有特定聚合度的 AOS 的潜力。在这里，从 中分离到一株降解海藻酸盐的菌株 M9，并在其基因组中预测了 5 种海藻酸盐裂解酶。这些假定的海藻酸盐裂解酶被表达，并分析了它们对海藻酸钠的降解产物。其中，AlyM2 主要产生三糖，占产物的 79.9%。AlyM2 是一种 PL6 裂解酶，与已鉴定的海藻酸盐裂解酶的序列同一性（≤28.3%）较低，可能基于序列比对采用了与其他 PL6 海藻酸盐裂解酶不同的催化机制。AlyM2 是一种双功能内切型裂解酶，在 30°C、pH8.0 和 0.5 M NaCl 下活性最高。AlyM2 主要从均聚物 M 块（PM）、均聚物 G 块（PG）或海藻酸钠中产生三糖，从海藻酸钠中产生 588.4 mg/g 的三糖，表明其在从这些多糖制备三糖方面有很大的潜力。
