Chair of General Microbiology, Technische Universität Dresden, 01217, Dresden, Germany.
Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), 46980, Paterna, Valencia, Spain.
Sci Rep. 2024 Feb 9;14(1):3319. doi: 10.1038/s41598-024-53592-1.
The PsdRSAB and ApsRSAB detoxification modules, together with the antimicrobial peptides (AMPs)-resistance determinants Dlt system and MprF protein, play major roles in the response to AMPs in Lacticaseibacillus paracasei BL23. Sensitivity assays with a collection of mutants showed that the PsdAB ABC transporter and the Dlt system are the main subtilin resistance determinants. Quantification of the transcriptional response to subtilin indicate that this response is exclusively regulated by the two paralogous systems PsdRSAB and ApsRSAB. Remarkably, a cross-regulation of the derAB, mprF and dlt-operon genes-usually under control of ApsR-by PsdR in response to subtilin was unveiled. The high similarity of the predicted structures of both response regulators (RR), and of the RR-binding sites support this possibility, which we experimentally verified by protein-DNA binding studies. ApsR-P shows a preferential binding in the order P > P > P > P. However, PsdR-P bound with similar apparent affinity constants to the four promoters. This supports the cross-regulation of derAB, mprF and the dlt-operon by PsdR. The possibility of cross-regulation at the level of RR-promoter interaction allows some regulatory overlap with two RRs controlling the expression of systems involved in maintenance of critical cell membrane functions in response to lantibiotics.
PsdRSAB 和 ApsRSAB 解毒模块，以及抗菌肽 (AMP) 抗性决定簇 Dlt 系统和 MprF 蛋白，在副干酪乳杆菌 BL23 对 AMP 的反应中起主要作用。使用一系列突变体的敏感性测定表明，PsdAB ABC 转运蛋白和 Dlt 系统是主要的枯草菌素抗性决定簇。对枯草菌素的转录反应进行定量表明，这种反应仅受两个平行的 PsdRSAB 和 ApsRSAB 系统调控。值得注意的是，在枯草菌素的作用下，derAB、mprF 和 dlt 操纵子基因通常受 ApsR 控制，由 PsdR 进行交叉调控。这两个响应调节剂 (RR) 的预测结构以及 RR 结合位点的高度相似性支持了这种可能性，我们通过蛋白质-DNA 结合研究实验验证了这一点。ApsR-P 优先以 P> P> P> P 的顺序结合。然而，PsdR-P 与四个启动子的结合具有相似的表观亲和力常数。这支持了 PsdR 对 derAB、mprF 和 dlt 操纵子的交叉调控。RR-启动子相互作用水平的交叉调控允许与两个 RR 进行一些调控重叠，这两个 RR 控制着参与维持对类细菌素的关键细胞膜功能的系统的表达。
