从伊氏交替单胞菌中发现的具有硫酯酶活性和 GNSL 基序但没有典型 GDSL 基序的新型 SGNH 家族水解酶 Ali5。
A novel SGNH family hydrolase Ali5 with thioesterase activity and a GNSL motif but without a classic GDSL motif from Altererythrobacter ishigakiensis.
机构信息
School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Jingkou District, Zhenjiang, 212013, People's Republic of China.
Key Laboratory of Marine Ecosystem and Biogeochemistry, State Oceanic Administration, Hangzhou, 310012, People's Republic of China.
出版信息
Biotechnol Lett. 2019 May;41(4-5):591-604. doi: 10.1007/s10529-019-02662-w. Epub 2019 Mar 20.
OBJECTIVE
We aimed to characterize a novel SGNH (Ser-Gly-Asn-His) family hydrolase from the annotated genome of marine bacteria with new features.
RESULTS
A novel esterase Ali5 from Altererythrobacter ishigakiensis has been identified and classified into SGNH family. Ali5 presented a novel GNSL (Gly-Asn-Ser-Leu(X)) motif that differs from the classic GDSL (Gly-Asp-Ser-Leu(X)) motif of SGNH family. The enzyme has esterase and thioesterase activity and exhibited apparent temperature and pH optima of 40 °C and pH 7.5 (in phosphate buffer), respectively. Ali5 was found to be halotolerant and thermostable, and exhibited strong resistance to several organic solvents and metal ions. The residue Tyr has a great influence on the catalytic activity, which was proved by site-directed mutagenesis and subsequent kinetic characterization.
CONCLUSION
The esterase Ali5 with esterase and thioesterase activities, salt and metal ions resistance and unique structural features was identified, which holds promise for research on the SGNH family of hydrolases.
目的
我们旨在从海洋细菌的注释基因组中鉴定具有新特征的新型 SGNH（Ser-Gly-Asn-His）家族水解酶。
结果
从伊氏交替单胞菌中鉴定出一种新型酯酶 Ali5，并将其分类为 SGNH 家族。Ali5 呈现出一种新颖的 GNSL（Gly-Asn-Ser-Leu(X)）基序，与 SGNH 家族的经典 GDSL（Gly-Asp-Ser-Leu(X)）基序不同。该酶具有酯酶和硫酯酶活性，在 40°C 和 pH 7.5（在磷酸盐缓冲液中）下表现出明显的最适温度和最适 pH。Ali5 表现出耐盐性和热稳定性，对几种有机溶剂和金属离子具有很强的抗性。通过定点突变和随后的动力学表征证明，残基 Tyr 对催化活性有很大影响。
结论
鉴定出具有酯酶和硫酯酶活性、耐盐和耐金属离子以及独特结构特征的酯酶 Ali5，这为研究 SGNH 家族的水解酶提供了希望。
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