Amy63, a novel type of marine bacterial multifunctional enzyme possessing amylase, agarase and carrageenase activities.
Amy63, a novel type of marine bacterial multifunctional enzyme possessing amylase, agarase and carrageenase activities.
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DOI：
10.1038/srep18726
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发表时间：
2016-01-04
影响因子：
4.6
通讯作者：
Sun C
中科院分区：
文献类型：
--
作者：
Liu G;Wu S;Jin W;Sun C
多功能酶是一种具有多种生理功能的酶，因此对生物体有益。多功能酶的表征对于研究人员了解生物体如何适应不同的环境挑战非常重要。在本研究中，我们报道了一种新型多功能酶Amy63的发现，这种酶是由海洋细菌溶藻弧菌63产生的。值得注意的是，Amy63具有淀粉酶、琼脂酶和角叉菜胶酶活性。Amy63是一种底物混杂型α-淀粉酶，底物优先顺序为淀粉、卡拉胶和琼脂。Amy63在较宽的温度和pH范围内保持了相当大的淀粉酶、角叉菜胶酶和琼脂酶的活性和稳定性，在温度60℃和pH 6.0时分别检测到最佳活性。此外，Amy63的异表达显著提高了大肠杆菌对淀粉、卡拉胶和琼脂的降解能力。基序搜索显示，Amy63编码序列中存在三个连续的糖基水解酶70 （GH70）家族同源物。结合Amy63的序列缺失和系统发育分析，GH70同源物被认为是酶乱交的决定因素。值得注意的是，这些酶存在于所有的生命王国中，从而为多功能酶的研究提供了一个扩展的视角。据我们所知，这是首次报道淀粉酶具有额外的琼脂酶和角叉菜胶酶活性。
A multifunctional enzyme is one that performs multiple physiological functions, thus benefiting the organism. Characterization of multifunctional enzymes is important for researchers to understand how organisms adapt to different environmental challenges. In the present study, we report the discovery of a novel multifunctional enzyme Amy63 produced by marine bacterium Vibrio alginolyticus 63. Remarkably, Amy63 possesses amylase, agarase and carrageenase activities. Amy63 is a substrate promiscuous α-amylase, with the substrate priority order of starch, carrageenan and agar. Amy63 maintains considerable amylase, carrageenase and agarase activities and stabilities at wide temperature and pH ranges, and optimum activities are detected at temperature of 60 °C and pH of 6.0, respectively. Moreover, the heteroexpression of Amy63 dramatically enhances the ability of E. coli to degrade starch, carrageenan and agar. Motif searching shows three continuous glycosyl hydrolase 70 (GH70) family homologs existed in Amy63 encoding sequence. Combining serial deletions and phylogenetic analysis of Amy63, the GH70 homologs are proposed as the determinants of enzyme promiscuity. Notably, such enzymes exist in all kingdoms of life, thus providing an expanded perspective on studies of multifunctional enzymes. To our knowledge, this is the first report of an amylase having additional agarase and carrageenase activities.