Structural and Biochemical Characterization of the Early and Late Enzymes in the Lignin β-Aryl Ether Cleavage Pathway from Sphingobium sp. SYK-6.
Structural and Biochemical Characterization of the Early and Late Enzymes in the Lignin β-Aryl Ether Cleavage Pathway from Sphingobium sp. SYK-6.
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木质素β-芳基乙醚裂解途径的早期和晚期酶的结构和生化表征来自鞘脂sp。 SYK-6。
DOI：
10.1074/jbc.m115.700427
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发表时间：
2016-05-06
期刊：
影响因子：
--
通讯作者：
Adams PD
中科院分区：
文献类型：
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作者：
Pereira JH;Heins RA;Gall DL;McAndrew RP;Deng K;Holland KC;Donohue TJ;Noguera DR;Simmons BA;Sale KL;Ralph J;Adams PD
在将木质纤维素生物质转化为糖并随后发酵为燃料的技术开发方面已经取得了很大进展。然而，植物木质素仍然是用于生产燃料或高价值化学品的未开发的材料来源。木质素的生物裂解已经在真菌中得到很好的表征，其中产生自由基中间体的酶被用于降解这种材料。相比之下，在鞘氨醇菌属SYK-6细菌中已经鉴定了木质素中发现的β-芳基醚单元的立体特异性裂解的分解代谢途径。β-芳基醚单元通常在木质素中丰富，对应于所有单体间键的50-70%。因此，对酶促β-芳基醚（β-醚）裂解的全面理解对于未来生物加工木质素及其分解产物的努力是重要的。NAD-依赖性脱乙酰酶（LigD、LigO和LigL）和谷胱甘肽-依赖性裂解酶LigG的晶体结构和生物化学表征为β-醚降解途径中的早期和晚期酶提供了新的见解。我们目前的辅因子和底物结合位点和这些酶的催化机制的详细信息，比较他们与其他已知的成员各自的家庭。有关Lig酶的信息为其催化机制提供了新的见解，并可以为使用源自植物木质素的芳香低聚物作为生物燃料和其他生物产品的有价值芳香化合物来源的未来策略提供信息。
There has been great progress in the development of technology for the conversion of lignocellulosic biomass to sugars and subsequent fermentation to fuels. However, plant lignin remains an untapped source of materials for production of fuels or high value chemicals. Biological cleavage of lignin has been well characterized in fungi, in which enzymes that create free radical intermediates are used to degrade this material. In contrast, a catabolic pathway for the stereospecific cleavage of β-aryl ether units that are found in lignin has been identified in Sphingobium sp. SYK-6 bacteria. β-Aryl ether units are typically abundant in lignin, corresponding to 50–70% of all of the intermonomer linkages. Consequently, a comprehensive understanding of enzymatic β-aryl ether (β-ether) cleavage is important for future efforts to biologically process lignin and its breakdown products. The crystal structures and biochemical characterization of the NAD-dependent dehydrogenases (LigD, LigO, and LigL) and the glutathione-dependent lyase LigG provide new insights into the early and late enzymes in the β-ether degradation pathway. We present detailed information on the cofactor and substrate binding sites and on the catalytic mechanisms of these enzymes, comparing them with other known members of their respective families. Information on the Lig enzymes provides new insight into their catalysis mechanisms and can inform future strategies for using aromatic oligomers derived from plant lignin as a source of valuable aromatic compounds for biofuels and other bioproducts.