College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China.
Int J Mol Sci. 2022 Jun 22;23(13):6928. doi: 10.3390/ijms23136928.
Panose is a type of functional sugar with diverse bioactivities. The enzymatic conversion bioprocess to produce high purity panose with high efficiency has become increasingly important. Here, a new neopullulanase (NPase), Amy117 from 703, was identified and characterized. Amy117 presented the optimal activity at pH 7.0 and 30 °C, its activity is over 40% at 10 °C and over 80% at 20 °C, which is cold-active. The enzyme cleaved α-1, 4-glycosidic linkages of pullulan to generate panose as the only hydrolysis product, and degraded cyclodextrins (CDs) and starch to glucose and maltose, with an apparent preference for CDs. Furthermore, Amy117 can produce 72.7 mg/mL panose with a conversion yield of 91% (/) based on 80 mg/mL pullulan. The sequence and structure analysis showed that the low proportion of Arg, high proportion of Asn and Gln, and high α-helix levels in Amy117 may contribute to its cold-active properties. Root mean square deviation (RMSD) analysis also showed that Amy117 is more flexible than two mesophilic homologues. Hence, we discovered a new high-efficiency panose-producing NPase, which so far achieves the highest panose production and would be an ideal candidate in the food industry.
泛醇是一种具有多种生物活性的功能性糖。酶转化生物工艺已成为生产高纯度、高效率泛醇的重要方法。在这里，我们鉴定并表征了来自 703 的一种新型普鲁兰酶（NPase）Amy117。Amy117 的最适反应条件为 pH7.0、30°C，10°C 时其活性超过 40%，20°C 时超过 80%，具有冷活性。该酶能特异性地切割普鲁兰中的α-1,4-糖苷键，生成泛醇作为唯一的水解产物，还能降解环糊精（CDs）和淀粉为葡萄糖和麦芽糖，对 CDs 具有明显偏好。此外，Amy117 可在 80mg/mL 普鲁兰的基础上，生产 72.7mg/mL 的泛醇，转化率为 91%（/）。序列和结构分析表明，Amy117 中的 Arg 比例低、Asn 和 Gln 比例高、α-螺旋含量高，可能与其冷活性特性有关。均方根偏差（RMSD）分析也表明，Amy117 比两个嗜中温同系物更具灵活性。因此，我们发现了一种新型高效的生产泛醇的 NPase，它迄今为止实现了最高的泛醇产量，有望成为食品工业的理想候选酶。
