Du Muxuan, Li Xue, Qi Weipeng, Li Yingjie, Wang Lushan
State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.
School of Life Sciences, Shandong University, Qingdao, China.
Front Microbiol. 2024 Jan 12;14:1333597. doi: 10.3389/fmicb.2023.1333597. eCollection 2023.
As the major component in the cell wall of brown algae, alginates are degradable by alginate lyases via β-elimination. Alginate lyases can be categorized into various polysaccharide lyase (PL) families, and PL7 family alginate lyases are the largest group and can be divided into six subfamilies. However, the major difference among different PL7 subfamilies is not fully understood. In this work, a marine alginate lyase, VaAly2, from ATCC 17749 belonging to the PL7_5 subfamily was identified and characterized. It displayed comparatively high alginolytic activities toward different alginate substrates and functions as a bifunctional lyase. Molecular docking and biochemical analysis suggested that VaAly2 not only contains a key catalyzing motif (HQY) conserved in the PL7 family but also exhibits some specific characters limited in the PL7_5 subfamily members, such as the key residues and a long loop1 structure around the active center. Our work provides insight into a loop structure around the center site which plays an important role in the activity and substrate binding of alginate lyases belonging to the PL7_5 subfamily.
作为褐藻细胞壁的主要成分，藻酸盐可被藻酸裂解酶通过β-消除作用降解。藻酸裂解酶可分为不同的多糖裂解酶（PL）家族，其中PL7家族的藻酸裂解酶是最大的一组，可分为六个亚家族。然而，不同PL7亚家族之间的主要差异尚未完全了解。在这项工作中，从属于PL7_5亚家族的ATCC 17749中鉴定并表征了一种海洋藻酸裂解酶VaAly2。它对不同的藻酸盐底物表现出较高的藻酸分解活性，并作为一种双功能裂解酶发挥作用。分子对接和生化分析表明，VaAly2不仅含有PL7家族中保守的关键催化基序（HQY），还表现出一些仅限于PL7_5亚家族成员的特定特征，如关键残基和活性中心周围的长环1结构。我们的工作揭示了中心位点周围的环结构，该结构在属于PL7_5亚家族的藻酸裂解酶的活性和底物结合中起重要作用。
