Dussurget O, Rodriguez M, Smith I
Department of Microbiology, Public Health Research Institute, New York, New York 10016, USA.
Mol Microbiol. 1996 Nov;22(3):535-44. doi: 10.1046/j.1365-2958.1996.1461511.x.
The mycobacterial ideR protein is a homologue of the diphtheria-toxin repressor DtxR. We have previously demonstrated that Mycobacterium tuberculosis ideR, like DtxR, represses transcription of Corynebacterium diphtheriae iron-regulated promoters in vivo and binds to C. diphtheriae operators in a metal-dependent manner in vitro. We show here that ideR mutants of M. smegmatis, constructed by allelic replacement, were defective in their ability to repress siderophore biosynthesis in the presence of iron. They were also more sensitive to hydrogen peroxide and had decreased levels of catalase/peroxidase (KatG) and manganese superoxide dismutase (Mn-SOD). This indicates that ideR is a negative regulator of siderophore production and is required for the response to superoxide- and hydrogen peroxide stress. We propose that ideR is the mycobacterial counterpart of the Escherichia coli Fur protein, i.e. It is a pleiotropic regulator that couples iron metabolism to the oxidative-stress response.
分枝杆菌的IdeR蛋白是白喉毒素阻遏物DtxR的同源物。我们之前已经证明，结核分枝杆菌的IdeR与DtxR一样，在体内可抑制白喉棒状杆菌铁调节启动子的转录，并且在体外以金属依赖的方式与白喉棒状杆菌的操纵基因结合。我们在此表明，通过等位基因替换构建的耻垢分枝杆菌IdeR突变体在铁存在的情况下抑制铁载体生物合成的能力存在缺陷。它们对过氧化氢也更敏感，过氧化氢酶/过氧化物酶（KatG）和锰超氧化物歧化酶（Mn-SOD）的水平降低。这表明IdeR是铁载体产生的负调节因子，是应对超氧化物和过氧化氢应激所必需的。我们提出，IdeR是大肠杆菌Fur蛋白在分枝杆菌中的对应物，即它是一种多效调节因子，将铁代谢与氧化应激反应联系起来。
