A non-blue laccase of Bacillus sp. GZB displays manganese-oxidase activity: A study of laccase characterization, Mn(II) oxidation and prediction of Mn(II) oxidation mechanism
A non-blue laccase of Bacillus sp. GZB displays manganese-oxidase activity: A study of laccase characterization, Mn(II) oxidation and prediction of Mn(II) oxidation mechanism
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芽孢杆菌属非蓝色漆酶。
DOI：
10.1016/j.chemosphere.2020.126619
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发表时间：
2020-08-01
期刊：
影响因子：
8.8
通讯作者：
An, Taicheng
中科院分区：
文献类型：
--
作者：
Das, Ranjit;Liang, Zhishu;An, Taicheng
漆酶是一类独特的多铜氧化酶，在许多工业和生物技术应用中具有潜在的生物催化作用。近年来，由于其对锰的氧化能力，在许多金属污染的场所得到了广泛的应用。在这里，我们证明了从芽孢杆菌获得的漆酶的锰(II)-氧化酶活性。GZB。将GZB的cota基因在大肠杆菌BL21中转化并高效表达。纯化的漆酶(LACREC3-漆酶)在610 nm处没有蓝漆酶中常见的峰。此外，LACREC3-漆酶分别以2，2‘-氮基-双(3-乙基苯并噻唑啉-6-磺酸)和丁香醛达嗪为底物，在不同的pH和温度下表现出较高的活力和稳定性。它在各种金属和酶抑制剂存在的情况下也能发挥作用。最值得注意的是，LACREC3-漆酶从锰(II)矿物中形成不溶于水的棕色锰(III)/锰(IV)-氧化物颗粒，表现出其锰(II)-氧化酶活性。除了天然的聚丙烯酰胺凝胶电泳法和缓冲试验外，我们还建立了一种琼脂糖凝胶平板法来评价漆酶的锰(II)氧化活性。此外，通过亮白蛋白蓝检测，共检测到44.45+/-0.45%的Mn(IV)-氧化物，其中5.87+/-0.61%在24 h后被自动氧化，并通过LACREC3-漆酶将Mn(II)转化为Mn(IV)的过程中用焦磷酸捕获Mn(III)的方法进一步预测了其氧化机理。总体而言，GZB漆酶具有良好的活性和稳定性，并具有氧化Mn(II)的能力。本研究首次报道了一种非蓝色漆酶，该酶具有Mn(II)-氧化酶活性。因此，它提供了一个新的发现，即在不同的金属污染环境中，锰(II)的氧化过程可能是一种有价值的锰(II)矿化途径。(C)2020爱思唯尔有限公司。保留所有权利。
Laccase, a unique class of multicopper oxidase, presents promising potential as a biocatalyst in many industrial and biotechnological applications. Recently, it has been significantly applied in many metal-polluted sites due to its Manganese (Mn)-oxidation ability. Here, we demonstrate the Mn(II)-oxidase activity of laccase obtained from Bacillus sp. GZB. The CotA gene of GZB was transformed in E. coli BL21 and overexpressed. The purified laccase (LACREC3-laccase) displayed the absence of a peak at 610 nm that is usually found in blue-laccase. Further, the LACREC3-laccase exhibited high activity and stability at different pH and temperatures with substrates 2, 2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonate) and syringaldazine, respectively. It also functioned in the presence of various metals and enzyme inhibitors. Most notably, LACREC3-laccase formed insoluble brown Mn(III)/Mn(IV)-oxide particles from Mn(II) mineral, exhibiting its Mn(II)-oxidase activity. In addition to native polyacrylamide gel electrophoresis and buffer test, we developed an 'agarose gel plate' assay to evaluate Mn(II) oxidation activity of laccase. Furthermore, using the leucoberbelin blue assay, a total of 44.45 +/- 0.45% Mn(IV)-oxides were quantified, in which 5.87 +/- 0.61% autoxidized after 24 h. The Mn(II) oxidation mechanisms were further predicted by trapping Mn(III) using pyrophosphate during Mn(II) to Mn(IV) conversion by LACREC3-laccase. Overall, the laccase of GZB has excellent activity and stability plus an ability to oxidize Mn(II). This study is the first report on a non-blue laccase, exhibiting Mn(II)-oxidase activity. Thus, it offers a novel finding of the Mn(II) oxidation processes that can be a valuable way of Mn(II)-mineralization in various metal-polluted environments. (C) 2020 Elsevier Ltd. All rights reserved.