Institute of Microbiology, Technische Universität Braunschweig, Spielmannstr. 7, Braunschweig, Germany.
Braunschweig Integrated Centre of Systems Biology BRICS, Technische Universität Braunschweig, Rebenring 56, Braunschweig, Germany.
Microb Biotechnol. 2017 Nov;10(6):1523-1534. doi: 10.1111/1751-7915.12851. Epub 2017 Aug 31.
The most efficient means of generating cellular energy is through aerobic respiration. Under anaerobic conditions, several prokaryotes can replace oxygen by nitrate as final electron acceptor. During denitrification, nitrate is reduced via nitrite, NO and N O to molecular nitrogen (N ) by four membrane-localized reductases with the simultaneous formation of an ion gradient for ATP synthesis. These four multisubunit enzyme complexes are coupled in four electron transport chains to electron donating primary dehydrogenases and intermediate electron transfer proteins. Many components require membrane transport and insertion, complex assembly and cofactor incorporation. All these processes are mediated by fine-tuned stable and transient protein-protein interactions. Recently, an interactomic approach was used to determine the exact protein-protein interactions involved in the assembly of the denitrification apparatus of Pseudomonas aeruginosa. Both subunits of the NO reductase NorBC, combined with the flavoprotein NosR, serve as a membrane-localized assembly platform for the attachment of the nitrate reductase NarGHI, the periplasmic nitrite reductase NirS via its maturation factor NirF and the N O reductase NosZ through NosR. A nitrate transporter (NarK2), the corresponding regulatory system NarXL, various nitrite (NirEJMNQ) and N O reductase (NosFL) maturation proteins are also part of the complex. Primary dehydrogenases, ATP synthase, most enzymes of the TCA cycle, and the SEC protein export system, as well as a number of other proteins, were found to interact with the denitrification complex. Finally, a protein complex composed of the flagella protein FliC, nitrite reductase NirS and the chaperone DnaK required for flagella formation was found in the periplasm of P. aeruginosa. This work demonstrated that the interactomic approach allows for the identification and characterization of stable and transient protein-protein complexes and interactions involved in the assembly and function of multi-enzyme complexes.
产生细胞能量最有效的方法是通过有氧呼吸。在无氧条件下，一些原核生物可以用硝酸盐替代氧气作为最终电子受体。在反硝化过程中，硝酸盐通过亚硝酸盐、一氧化氮和一氧化二氮被还原为氮气（N2），这是由四个定位于膜上的还原酶完成的，同时形成一个用于 ATP 合成的离子梯度。这四个多亚基酶复合物通过电子供体初级脱氢酶和中间电子转移蛋白与四个电子传递链耦合。许多组件需要膜运输和插入、复杂组装和辅助因子掺入。所有这些过程都由精细调节的稳定和瞬态蛋白-蛋白相互作用介导。最近，一种相互作用组学方法被用于确定与铜绿假单胞菌反硝化装置组装相关的确切蛋白-蛋白相互作用。NO 还原酶 NorBC 的两个亚基，与黄素蛋白 NosR 结合，作为硝酸盐还原酶 NarGHI、通过其成熟因子 NirF 连接的周质亚硝酸盐还原酶 NirS 和通过 NosR 连接的 N O 还原酶 NosZ 的附着的膜定位组装平台。硝酸盐转运蛋白（NarK2）、相应的调节系统 NarXL、各种亚硝酸盐（NirEJMNQ）和 N O 还原酶（NosFL）成熟蛋白也是该复合物的一部分。初级脱氢酶、ATP 合酶、TCA 循环的大多数酶、SEC 蛋白输出系统以及许多其他蛋白质被发现与反硝化复合物相互作用。最后，在铜绿假单胞菌的周质中发现了一个由鞭毛蛋白 FliC、亚硝酸盐还原酶 NirS 和鞭毛形成所需的伴侣蛋白 DnaK 组成的蛋白质复合物。这项工作表明，相互作用组学方法允许识别和表征参与多酶复合物组装和功能的稳定和瞬态蛋白-蛋白复合物和相互作用。
