Functional roles of multiple Ton complex genes in a <i>Sphingobium</i> degrader of lignin-derived aromatic compounds
Functional roles of multiple Ton complex genes in a <i>Sphingobium</i> degrader of lignin-derived aromatic compounds
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多个 Ton 复合物基因在木质素衍生芳香族化合物<i>Sphingobium</i>降解剂中的功能作用
DOI：
10.1101/2021.08.06.455174
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Masai Eiji
中科院分区：
文献类型：
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作者：
Fujita Masaya;Yano Shodai;Shibata Koki;Kondo Mizuki;Hishiyama Shojiro;Kamimura Naofumi;Masai Eiji
TonB依赖的转运体(TBDTs)利用位于内膜的TonB-ExbB-ExbD复合体传递的质子动力能量，介导营养物质的外膜转运。最近，我们在Sphingobiumsp中发现了编码一个TBDT的ddvT，它负责摄取一个5，5型木质素衍生的二聚体。菌株SYK-6。此外，SYK-6衍生菌株ddvtin的过表达增强了其摄取能力，提高了平台化学生产的速度。因此，了解木质素衍生芳香族化合物的吸收系统是基于微生物转化的木质素价态的基础。在这里，我们研究了SYK-6中的多重子B-、exbB-和类似于bD的基因是否有助于木质素衍生的芳香族物质的外膜运输。B2-6和bB3的断裂并没有降低SYK-6转化或生长在木质素衍生芳烃上的能力。相反，不受干扰的启动子B1-exbB1-exbD1-exbD2操纵子基因的导入促进了β-O-4-、β-5-、β-1-、β-β-和5，5-型二聚体和单体的转化，如阿魏酸、香草酸、丁香酸和原儿茶酸。这些结果表明，涉及TONB1操纵子基因的TonB依赖的摄取负责上述芳烃的外膜转运。此外，exbB2/tolQandexbD3/tolR构成了维持外膜完整性的Tol-Pal系统。
TonB-dependent transporters (TBDTs) mediate outer membrane transport of nutrients using the energy derived from proton motive force transmitted from the TonB–ExbB–ExbD complex localized in the inner membrane. Recently, we discoveredddvTencoding a TBDT responsible for the uptake of a 5,5-type lignin-derived dimer inSphingobiumsp. strain SYK-6. Furthermore, overexpression ofddvTin an SYK-6-derivative strain enhanced its uptake capacity, improving the rate of platform chemical production. Thus, understanding the uptake system of lignin-derived aromatics is fundamental for microbial conversion-based lignin valorization. Here we examined whether multipletonB-,exbB-, andexbD-like genes in SYK-6 contribute to the outer membrane transport of lignin-derived aromatics. The disruption oftonB2–6andexbB3did not reduce the capacity of SYK-6 to convert or grow on lignin-derived aromatics. In contrast, the introduction of thetonB1–exbB1–exbD1–exbD2operon genes into SYK-6, which could not be disrupted, promoted the conversion of β-O-4-, β-5-, β-1-, β-β-, and 5,5-type dimers and monomers, such as ferulate, vanillate, syringate, and protocatechuate. These results suggest that TonB-dependent uptake involving thetonB1operon genes is responsible for the outer membrane transport of the above aromatics. Additionally,exbB2/tolQandexbD3/tolRwere suggested to constitute the Tol-Pal system that maintains the outer membrane integrity.