A TonB-dependent receptor constitutes the outer membrane transport system for a lignin-derived aromatic compound
A TonB-dependent receptor constitutes the outer membrane transport system for a lignin-derived aromatic compound
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DOI：
10.1038/s42003-019-0676-z
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发表时间：
2019-11-22
影响因子：
5.9
通讯作者：
Masai, Eiji
中科院分区：
文献类型：
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作者：
Fujita, Masaya;Mori, Kosuke;Masai, Eiji
TonB依赖性受体（TBDR）介导底物特异性转运穿过外膜，利用源自位于内膜中的TonB-ExbB-ExbD复合物（TonB系统）传递的质子动力的能量。虽然已经确定了一些参与铁载体、维生素B12和维生素B14摄取的TonB系统，但它们参与芳香族化合物的摄取和催化以前是未知的。在这里，我们表明，来自木质素的联苯化合物的外膜运输是由能够降解木质素衍生的芳香族化合物，鞘氨醇菌属菌株SYK-6的革兰氏阴性细菌中的TonB系统介导的。此外，我们发现相应TBDR基因的过表达增强了这种联苯化合物的摄取，有助于提高平台化学品生产的速率。我们的研究结果将提供一个重要的基础，建立优化的工程菌株用于木质素增值。
TonB-dependent receptors (TBDRs) mediate substrate-specific transport across the outer membrane, utilizing energy derived from the proton motive force transmitted from the TonB -ExbB-ExbD complex located in the inner membrane (TonB system). Although a number of TonB systems involved in the uptake of siderophores, vitamin B12 and saccharides have been identified, their involvement in the uptake and catabolism of aromatic compounds was previously unknown. Here, we show that the outer membrane transport of a biphenyl compound derived from lignin is mediated by the TonB system in a Gram-negative bacterium capable of degrading lignin-derived aromatic compounds, Sphingobium sp. strain SYK-6. Furthermore, we found that overexpression of the corresponding TBDR gene enhanced the uptake of this biphenyl compound, contributing to the improved rate of platform chemical production. Our results will provide an important basis for establishing engineered strains optimized for use in lignin valorisation.