College of Food and Biological Engineering, Jimei University, Xiamen 361021, China.
Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Xiamen 361021, China.
Mar Drugs. 2022 Feb 6;20(2):126. doi: 10.3390/md20020126.
As an important enzyme involved in the marine carbon cycle, alginate lyase has received extensive attention because of its excellent degradation ability on brown algae, which is widely utilized for alginate oligosaccharide preparation or bioethanol production. In comparison with endo-type alginate lyases (PL-5, PL-7, and PL-18 families), limited studies have focused on PL-17 family alginate lyases, especially for those with special characteristics. In this study, a novel PL-17 family alginate lyase, Aly23, was identified and cloned from the marine bacterium ASY5. Aly23 exhibited maximum activity at 35 °C and retained 48.93% of its highest activity at 4 °C, representing an excellent cold-adaptation property. Comparative molecular dynamics analysis was implemented to explore the structural basis for the cold-adaptation property of Aly23. Aly23 had a high substrate preference for poly β-D-mannuronate and exhibited both endolytic and exolytic activities; its hydrolysis reaction mainly produced monosaccharides, disaccharides, and trisaccharides. Furthermore, the enzymatic hydrolyzed oligosaccharides displayed good antioxidant activities to reduce ferric and scavenge radicals, such as hydroxyl, ABTS, and DPPH. Our work demonstrated that Aly23 is a promising cold-adapted biocatalyst for the preparation of natural antioxidants from brown algae.
作为一种参与海洋碳循环的重要酶，褐藻酸裂解酶因其对褐藻具有优异的降解能力而受到广泛关注，被广泛用于褐藻寡糖的制备或生物乙醇的生产。与内型褐藻酸裂解酶（PL-5、PL-7 和 PL-18 家族）相比，对 PL-17 家族褐藻酸裂解酶的研究较少，特别是对那些具有特殊特性的酶。在本研究中，从海洋细菌 ASY5 中鉴定并克隆了一种新型的 PL-17 家族褐藻酸裂解酶 Aly23。Aly23 在 35°C 时表现出最大活性，在 4°C 时保留了其最高活性的 48.93%，表现出优异的耐冷特性。通过比较分子动力学分析，探讨了 Aly23 耐冷特性的结构基础。Aly23 对聚 β-D-甘露糖酸盐具有较高的底物偏好性，表现出内切和外切活性；其水解反应主要产生单糖、二糖和三糖。此外，酶解得到的寡糖具有良好的抗氧化活性，能够还原铁离子和清除自由基，如羟基、ABTS 和 DPPH。我们的工作表明，Aly23 是一种很有前途的耐冷生物催化剂，可用于从褐藻中制备天然抗氧化剂。
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