J Agric Food Chem. 2019 May 15;67(19):5587-5595. doi: 10.1021/acs.jafc.9b01123. Epub 2019 Apr 30.
Maltooligosyltrehalose synthase (MTSase) is a key enzyme in trehalose production. MTSase from Arthrobacter ramosus has poor thermostability, limiting its industrial use. In this study, mutant G415P was obtained by directed evolution and S361R/S444E was subsequently generated based on a structure analysis of the region around G415. The t of G415P and S361R/S444E at 60 °C increased by 3.0- and 3.2-fold, respectively, compared with the wild-type enzyme. A triple mutant (G415P/S361R/S444E) was obtained through a combination of the above mutants, and its t significantly increased by 19.7-fold. Kinetic and thermodynamic stability results showed that the T and T values of the triple mutant increased by 7.1 and 7.3 °C, respectively, compared with those of the wild-type enzyme. When the triple mutant was used in trehalose production, the yield reached 71.6%, higher than the 70.3% achieved with the wild-type. Thus, the mutant has a potential application for industrial trehalose production.
甘露寡糖海藻糖合酶（MTSase）是海藻糖生产的关键酶。节杆菌来源的 MTSase 热稳定性差，限制了其工业应用。本研究通过定向进化获得了突变体 G415P，并根据 G415 周围区域的结构分析，进一步生成了 S361R/S444E。与野生型酶相比，G415P 和 S361R/S444E 的 t 分别提高了 3.0 倍和 3.2 倍。通过组合上述突变体获得了三重突变体（G415P/S361R/S444E），其 t 显著提高了 19.7 倍。动力学和热力学稳定性结果表明，与野生型酶相比，三重突变体的 T 和 T 值分别提高了 7.1°C 和 7.3°C。当三重突变体用于生产海藻糖时，产率达到 71.6%，高于野生型的 70.3%。因此，该突变体具有在工业生产海藻糖中的潜在应用。
