Bacterial type IV secretion systems (T4SSs) can mediate conjugation. The T4SS from Neisseria gonorrhoeae possesses the unique ability to mediate DNA secretion into the extracellular environment. The N. gonorrhoeae T4SS can be grouped with F‐type conjugative T4SSs based on homology. We tested 17 proteins important for DNA secretion by N. gonorrhoeae for protein interactions. The BACTH‐TM bacterial two‐hybrid system was successfully used to study periplasmic interactions. By determining if the same interactions were observed for F‐plasmid T4SS proteins and when one interaction partner was replaced by the corresponding protein from the other T4SS, we aimed to identify features associated with the unique function of the N. gonorrhoeae T4SS as well as generic features of F‐type T4SSs. For both systems, we observed already described interactions shared by homologs from other T4SSs as well as new and described interactions between F‐type T4SS‐specific proteins. Furthermore, we demonstrate, for the first‐time, interactions between proteins with homology to the conserved T4SS outer membrane core proteins and F‐type‐specific proteins and we confirmed two of them by co‐purification. The F‐type‐specific protein TraH_N was found to localize to the outer membrane and the presence of significant amounts of TraH_N in the outer membrane requires TraG_N.

中文翻译：

---

两个 F 型 IV 型分泌系统内部和之间的蛋白质相互作用。

IV 型细菌分泌系统 (T4SSs) 可以介导结合。来自淋病奈瑟菌的 T4SS具有将 DNA 分泌到细胞外环境中的独特能力。在淋病奈瑟氏球菌T4SS可以与基于同源性的F型共轭T4SSs进行分组。我们测试了 17 种对N分泌 DNA 很重要的蛋白质。淋病用于蛋白质相互作用。BACTH-TM细菌双杂交系统成功用于研究周质相互作用。通过确定 F 质粒 T4SS 蛋白是否观察到相同的相互作用，以及当一个相互作用伙伴被另一个 T4SS 的相应蛋白质取代时，我们旨在确定与 F 质粒 T4SS 的独特功能相关的特征。N. gonorrhoeae T4SS 以及 F 型 T4SSs 的一般特征。对于这两个系统，我们观察到来自其他 T4SS 的同源物已经描述的相互作用以及 F 型 T4SS 特异性蛋白质之间新的和描述的相互作用。此外，我们首次证明了与保守的 T4SS 外膜核心蛋白和 F 型特异性蛋白具有同源性的蛋白质之间的相互作用，我们通过共纯化证实了其中的两个。发现 F 型特异性蛋白 TraH _N定位于外膜，外膜中大量 TraH _N的存在需要 TraG _N。