ICV-Institut Charles Viollette, UMR Transfrontalière BioEcoAgro 1158, University Lille, INRAE, University Liège, UPJV, YNCREA, University Artois, University Littoral Côte d'Opale, 59000 Lille, France.
Biochemistry and Molecular Biology Laboratory, Faculty of Biology, Alexandru Ioan Cuza University of Iasi, Carol I Blvd, no. 20A, 700506 Iasi, Romania.
Int J Mol Sci. 2023 Jan 12;24(2):1517. doi: 10.3390/ijms24021517.
Enterocin DD14 (EntDD14) is a two-peptide leaderless bacteriocin produced by the 14 strain previously isolated from meconium. This bacteriocin is mainly active against Gram-positive bacteria. Leaderless bacteriocins do not undergo post-translational modifications and are therefore immediately active after their synthesis. As a result, the cells that produce such bacteriocins have developed means of protection against them which often involve transport systems. In this and our previous work, we constructed different mutants deleted in the genes involved in the transport functions, thus covering all the supposed components of this transport system, using ATCC 33090 as the indicator strain to assess the activity of externalized EntDD14. We also assessed the self-resistance of the WT and all its engineered derivative mutants against EntDD14, provided extracellularly, in order to evaluate their self-resistance. The results obtained highlight that the ABC transporter constituted by the DdG, H, I, and J proteins contributes to EntDD14 export as well as resistance to an external supply of EntDD14. Our results also have established the essential role of the DdE and DdF proteins as primary transporters dedicated to the externalization of EntDD14. Moreover, the in silico data showed that DdE and DdF appear to assemble in a formation that forms an essential channel for the exit of EntDD14. This channel DdEF may interact with the ABC transporter DdGHIJ in order to control the flow of bacteriocin across the membrane, although the nature of this interaction remains to be elucidated.
肠球菌素 DD14（EntDD14）是一种由先前从胎粪中分离出的 14 株产生的两肽无信号肽细菌素。这种细菌素主要对革兰氏阳性菌有活性。无信号肽细菌素不会发生翻译后修饰，因此在合成后立即具有活性。因此，产生这种细菌素的细胞已经开发出了针对它们的保护机制，这通常涉及运输系统。在本研究和我们之前的工作中，我们构建了不同的基因缺失突变体，这些突变体缺失了参与运输功能的基因，从而涵盖了这个运输系统的所有假定成分，使用 ATCC 33090 作为指示菌株来评估外化 EntDD14 的活性。我们还评估了 WT 及其所有工程衍生突变体对提供的外源性 EntDD14 的自我抗性，以评估它们的自我抗性。获得的结果表明，由 DdG、H、I 和 J 蛋白组成的 ABC 转运体有助于 EntDD14 的外排以及对 EntDD14 外部供应的抗性。我们的结果还确定了 DdE 和 DdF 蛋白作为专门用于外化 EntDD14 的初级转运蛋白的重要作用。此外，计算机模拟数据表明，DdE 和 DdF 似乎组装成一个形成 EntDD14 出口的必需通道的结构。这个通道 DdEF 可能与 ABC 转运体 DdGHIJ 相互作用，以控制细菌素穿过膜的流动，尽管这种相互作用的性质仍有待阐明。
