Department of Public Health, College of Veterinary Medicine, Jeonbuk National University, Republic of Korea.
Biochemistry & Molecular Biology Department, Mayo Clinic, Rochester, Minnesota, USA 55905.
Gut Microbes. 2022 Jan-Dec;14(1):2064705. doi: 10.1080/19490976.2022.2064705.
This study investigates the interplay between Lon protease and catalase-peroxidase (KatG) in relation to virulence modulation and the response to oxidative stress in Typhimurium (ST). Proteomic comparison of ST wild-type and deletion mutant led to the recognition of a highly expressed KatG protein product among five other protein candidates that were significantly affected by deletion. By employing a bacterium two-hybrid assay (B2H), we demonstrated that the catalytic domain of Lon protease potentially interacts with the KatG protein that leads to proteolytic cleavage. Assessment of virulence gene expression in single and double and mutants revealed to be a potential positive modulator of both pathogenicity Island-1 (SPI-1) and -2, while significantly affected SPI-1 genes. ST double deletion mutant, ∆ was more susceptible to survival defects within macrophage-like cells and exhibited meager colonization of the mouse spleen compared to the single deletion mutants. The findings reveal a previously unknown function of Lon and KatG interaction in virulence. Taken together, our experiments demonstrate the importance of Lon and KatG to cope with oxidative stress, for intracellular survival and virulence of .
本研究探讨了 Lon 蛋白酶与过氧化氢酶-过氧化物酶（KatG）之间的相互作用与毒力调节以及鼠伤寒沙门氏菌（ST）对氧化应激的反应之间的关系。ST 野生型和 缺失突变体的蛋白质组比较导致在另外五个受 缺失显著影响的蛋白质候选物中识别出高度表达的 KatG 蛋白产物。通过采用细菌双杂交测定（B2H），我们证明 Lon 蛋白酶的催化结构域可能与导致蛋白水解切割的 KatG 蛋白相互作用。在单突变体和 及 双突变体中评估毒力基因表达，结果表明 可能是 SPI-1 和 SPI-2 的潜在正调节剂，而 则显著影响 SPI-1 基因。与单缺失突变体相比，ST 双缺失突变体 ∆在巨噬样细胞中更易出现生存缺陷，且在小鼠脾脏中的定植能力较差。这些发现揭示了 Lon 和 KatG 相互作用在毒力中的一个先前未知的功能。总之，我们的实验证明了 Lon 和 KatG 对于应对氧化应激、细胞内存活和 ST 的毒力的重要性。
