Characterization of two 1,2,4-trihydroxybenzene 1,2-dioxygenases from Phanerochaete chrysosporium
Characterization of two 1,2,4-trihydroxybenzene 1,2-dioxygenases from Phanerochaete chrysosporium
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DOI：
10.1007/s00253-022-12007-9
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发表时间：
2022-06-10
影响因子：
5
通讯作者：
Shimizu, Motoyuki
中科院分区：
文献类型：
--
作者：
Kato, Hiroyuki;Furusawa, Terumi T.;Shimizu, Motoyuki
木质素是自然界中最丰富的芳香族化合物，在碳循环中发挥着重要作用。白腐真菌是能够有效降解木质素的微生物。来自这些真菌的酶具有特殊的氧化潜力，并且对于改善生物过程（例如有机污染物的降解）变得越来越重要。本研究的目的是鉴定参与木质素降解担子菌 Phanerochaete chrysosporium 中木质素衍生的芳香族 1,2,4-三羟基苯 (THB) 环裂解的酶。两种内二醇双加氧酶 (IDD) PcIDD1 和 PcIDD2 被鉴定为重组蛋白，并在大肠杆菌中产生。在 O-2 存在的情况下，PcIDD1 和 PcIDD2 分别作用于作为底物的八种和两种 THB 衍生物。 PcIDD1 和 PcIDD2 催化木质素衍生片段的环裂解，例如 6-甲氧基-1,2,4-三羟基苯 (6-MeOTHB) 和 3-甲氧基-1,2-儿茶酚。目前的研究还揭示了丁香酸（SA）被真菌细胞转化为5-羟基香草酸、2,6-二甲氧基氢醌和6-MeOTHB，这表明PcIDD1和PcIDD2可能参与了6-MeOTHB的芳环裂变而降解SA。这是第一项显示 IDD 超家族成员的 6-MeOTHB 双加氧酶活性的研究。这些发现突出了 PcIDD 独特且广泛的底物光谱，使其成为生物技术应用的有吸引力的候选者。
Lignin is the most abundant aromatic compound in nature, and it plays an important role in the carbon cycle. White-rot fungi are microbes that are capable of efficiently degrading lignin. Enzymes from these fungi possess exceptional oxidative potential and have gained increasing importance for improving bioprocesses, such as the degradation of organic pollutants. The aim of this study was to identify the enzymes involved in the ring cleavage of the lignin-derived aromatic 1,2,4-trihydroxybenzene (THB) in Phanerochaete chrysosporium, a lignin-degrading basidiomycete. Two intradiol dioxygenases (IDDs), PcIDD1 and PcIDD2, were identified and produced as recombinant proteins in Escherichia coli. In the presence of O-2, PcIDD1 and PcIDD2 acted on eight and two THB derivatives, respectively, as substrates. PcIDD1 and PcIDD2 catalyze the ring cleavage of lignin-derived fragments, such as 6-methoxy-1,2,4-trihydroxybenzene (6-MeOTHB) and 3-methoxy-1,2-catechol. The current study also revealed that syringic acid (SA) was converted to 5-hydroxyvanillic acid, 2,6-dimethoxyhydroquinone, and 6-MeOTHB by fungal cells, suggesting that PcIDD1 and PcIDD2 may be involved in aromatic ring fission of 6-MeOTHB for SA degradation. This is the first study to show 6-MeOTHB dioxygenase activity of an IDD superfamily member. These findings highlight the unique and broad substrate spectra of PcIDDs, rendering it an attractive candidate for biotechnological application.