Catalytic properties of a short manganese peroxidase from Irpex lacteus F17 and the role of Glu166 in the Mn2+-independent activity
Catalytic properties of a short manganese peroxidase from Irpex lacteus F17 and the role of Glu166 in the Mn2+-independent activity
复制标题
IrpexlacteusF17 的短锰过氧化物酶的催化特性以及 Glu166 在 Mn2 独立活性中的作用
DOI：
10.1016/j.ijbiomac.2019.06.065
复制
发表时间：
2019-09-01
影响因子：
8.2
通讯作者：
Jia, Rong
中科院分区：
文献类型：
--
作者：
Li, Liuqing;Liu, Binjie;Jia, Rong
II-MnP 1（GenBank：AG086670.2）已通过序列分析确认为来自Irpex lacteus F17（CCTCC AF 2014020）的短锰过氧化物酶（MnP）。要调查的催化性能，典型的芳香族底物的氧化和愈创木酚氧化的途径，由Il-MnP 1，无论是在存在和不存在的Mn 2+在pH 4.0或pH 7.4，进行了分析。结果表明，I1-MnP 1表现出更高的氧化活性，在Mn 2+的存在下比在Mn 2+的情况下对大多数选定的基板在pH 4.0。此外，相似的产物组成表明，愈创木酚的氧化主要属于一系列聚合反应的自由基引发的Il-MnP 1，无论是在存在和不存在的Mn 2+在pH 4.0或7.4。此外，通过定点突变，发现了两个突变体（E166 G，E166 Q），以提高Mn 2+非依赖性氧化活性显着。E166 G和E166 Q对2，6-二甲氧基苯酚的催化氧化效率（KcadK_i）分别是11-MnP 1的170倍和34倍。研究表明，在Mn ~（2+）依赖性和非依赖性氧化之间，I-MnPl的催化性能存在一定的差异。更重要的是，残基（E166）与短MnP的Mn 2+非依赖性活性相关。(C)2019爱思唯尔B. V.保留所有权利。
II-MnP1 (GenBank: AG086670.2) has been confirmed by sequence analysis as a short manganese peroxidase (MnP) from Irpex lacteus F17 (CCTCC AF 2014020). To investigate the catalytic properties, the oxidation of typical aromatic substrates and the pathways of guaiacol oxidation by Il-MnP1, both in the presence and absence of Mn2+ at either pH 4.0 or pH 7.4, were analyzed. Results showed that I1-MnP1 exhibited higher oxidative activity in the presence of Mn2+ than in the absence of Mn2+ toward the majority of the selected substrates at pH 4.0. Additionally, the similar product compositions suggested that the oxidation of guaiacol mainly belongs to a series of polymeric reactions of radicals initiated by Il-MnP1, whether they were in the presence and absence of Mn2+ at either pH 4.0 or 7.4. Furthermore, two variants (E166G, E166Q) were found using site-directed mutagenesis, to improve the Mn2+-independent oxidative activity significantly. The catalytic efficiency (KcadK,) of El 66G and El 66Q in 2, 6-dimethoxyphenol oxidation was higher than Il-MnP1 by 170 and 34 times, respectively. The study revealed certain differences in catalytic properties between Mn2+ dependent and independent oxidation by Il-MnPl. More importantly, a residue (E166) was related to the Mn2+-independent activity of a short MnP. (C) 2019 Elsevier B.V. All rights reserved.