Catalytic profile of Arabidopsis peroxidases, AtPrx-2, 25 and 71, contributing to stem lignification.
Catalytic profile of Arabidopsis peroxidases, AtPrx-2, 25 and 71, contributing to stem lignification.
复制标题
DOI：
10.1371/journal.pone.0105332
复制
发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Tsutsumi Y
中科院分区：
文献类型：
--
作者：
Shigeto J;Nagano M;Fujita K;Tsutsumi Y
木质素是由木质素前体氧化偶联产生的芳香族杂聚物，包括木质素单体（对香豆醇、松柏醇和新树醇）、低聚物和聚合物。虽然植物过氧化物酶已被证明可以催化单脂醇的氧化偶联，但经过充分研究的植物过氧化物酶，如辣根过氧化物酶C （HRP-C）和AtPrx53，对sinapyl醇的氧化活性相当低。这种特性差异引起了植物过氧化物酶氧化新树醇和木质素低聚物和聚合物机理的争议。本研究探讨了三种植物过氧化物酶AtPrx2、AtPrx25和AtPrx71的氧化活性，这三种酶已被证明参与拟南芥茎的木质素化过程。这些过氧化物酶的重组蛋白（rAtPrxs）在大肠杆菌中作为包涵体产生，并成功地重新折叠以产生其活性形式。rAtPrx2、rAtPrx25和rAtPrx71可以氧化两种紫丁香基化合物（2,6-二甲氧基苯酚和丁香醛），这两种化合物作为模型单酚化合物，具有比HRP-C和rAtPrx53更高的特异性活性。有趣的是，rAtPrx2和rAtPrx71比愈创木酚更有效地氧化丁香基化合物。此外，以铁细胞色素c为底物的实验表明，AtPrx2、AtPrx25和AtPrx71具有氧化大分子的能力。这种特性可能源于一种蛋白质自由基。这些结果表明，负责木质素聚合的植物过氧化物酶能够直接氧化所有木质素前体。
Lignins are aromatic heteropolymers that arise from oxidative coupling of lignin precursors, including lignin monomers (p-coumaryl, coniferyl, and sinapyl alcohols), oligomers, and polymers. Whereas plant peroxidases have been shown to catalyze oxidative coupling of monolignols, the oxidation activity of well-studied plant peroxidases, such as horseradish peroxidase C (HRP-C) and AtPrx53, are quite low for sinapyl alcohol. This characteristic difference has led to controversy regarding the oxidation mechanism of sinapyl alcohol and lignin oligomers and polymers by plant peroxidases. The present study explored the oxidation activities of three plant peroxidases, AtPrx2, AtPrx25, and AtPrx71, which have been already shown to be involved in lignification in the Arabidopsis stem. Recombinant proteins of these peroxidases (rAtPrxs) were produced in Escherichia coli as inclusion bodies and successfully refolded to yield their active forms. rAtPrx2, rAtPrx25, and rAtPrx71 were found to oxidize two syringyl compounds (2,6-dimethoxyphenol and syringaldazine), which were employed here as model monolignol compounds, with higher specific activities than HRP-C and rAtPrx53. Interestingly, rAtPrx2 and rAtPrx71 oxidized syringyl compounds more efficiently than guaiacol. Moreover, assays with ferrocytochrome c as a substrate showed that AtPrx2, AtPrx25, and AtPrx71 possessed the ability to oxidize large molecules. This characteristic may originate in a protein radical. These results suggest that the plant peroxidases responsible for lignin polymerization are able to directly oxidize all lignin precursors.
登录
查看更多内容
影响因子：
4.3
作者：
Herrero, Joaquin;Fernandez-Perez, Francisco;Miguel Zapata, Jose
通讯作者：
Miguel Zapata, Jose
影响因子：
6.9
作者：
Ruiz-Duenas, Francisco J.;Morales, Maria;Martinez, Angel T.
通讯作者：
Martinez, Angel T.
影响因子：
3.8
作者：
Sasaki, Shinya;Nonaka, Daisuke;Kondo, Ryuichiro
通讯作者：
Kondo, Ryuichiro
影响因子：
2.9
作者：
Kobayashi, T;Taguchi, H;Tanahashi, M
通讯作者：
Tanahashi, M
影响因子：
2.8
作者：
Li, YH;Kajita, S;Morohoshi, N
通讯作者：
Morohoshi, N