魔芋葡甘露聚糖(KGM)是一种来源于魔芋的天然多糖,由于其众多的有益性能,已广泛应用于各个领域。然而,KGM的高粘度和吸水性限制了其应用。与KGM相比,魔芋葡甘露聚糖寡糖(KGMOS)具有较高的水溶性和较强的应用价值。在本文中,从克雷伯菌grimontii中克隆了一种新的甘露聚糖酶KgManA,以开发一种新的KGMOS产生酶。生物信息学分析表明,KgManA与其他酶的结构相似性小于18.33%。系统发育分析表明,KgManA与含有CMB35结构域的传统甘露聚糖酶共享不同的分支,表明它是一种新型的甘露聚糖酶.然后,测定酶学性质并表征底物特异性。令人惊讶的是,KgManA在3.0至10.0的非常宽的pH范围内稳定;它具有特殊的底物特异性,似乎仅对侧链中没有半乳糖的甘露聚糖具有活性。此外,模拟了酶的三维结构,并进行了甘露糖底物的分子对接。据我们所知,这是第一份表征酶学性质和模拟来自K.grimontii的甘露聚糖酶结构的报告。这项工作将有助于新型K.grimontii衍生的甘露聚糖酶的开发和表征。上述结果表明KgManA是生产KGMOS的有前途的工具。
Konjac glucomannan (KGM) is a natural polysaccharide derived from konjac, which has been widely used in various fields due to its numerous beneficial properties. However, the high viscosity and water absorption of KGM limit its application. Compared with KGM, Konjac glucomannan oligosaccharides (KGMOS) have higher water solubility and stronger application value. In this paper, a novel mannanase KgManA was cloned from Klebsiella grimontii to develop a new KGMOS-producing enzyme. Bioinformatic analysis shows that the structural similarity between KgManA and other enzymes was less than 18.33%. Phylogenetic analysis shows that KgManA shares different branches with the traditional mannanases containing the CMB35 domain, indicating that it is a novel mannanase. Then, the enzymatic properties were determined and substrate specificity was characterized. Surprisingly, KgManA is stable in a very wide pH range of 3.0 to 10.0; it has a special substrate specificity and seems to be active only for mannans without galactose in the side chain. Additionally, the three-dimensional structure of the enzyme was simulated and molecular docking of the mannotetraose substrate was performed. As far as we know, this is the first report to characterize the enzymatic properties and to simulate the structure of mannanase from K. grimontii. This work will contribute to the development and characterization of novel K. grimontii-derived mannanases. The above results indicate that KgManA is a promising tool for the production of KGMOS.