Klebba Phillip E, Charbit Alain, Xiao Qiaobin, Jiang Xiaoxu, Newton Salete M
Department of Biochemistry, Kansas State University, Manhattan, KS 66506, USA.
Mol Membr Biol. 2012 May-Jun;29(3-4):69-86. doi: 10.3109/09687688.2012.694485.
Listeria monocytogenes, the causative agent of listeriosis, is a virulent foodborne Gram-positive bacterial pathogen, with 20-30% mortality. It has a broad ability to transport iron, either in the form of ferric siderophores, or by extracting it from mammalian iron binding proteins. In this review we focus on the mechanisms of ferric siderophore and haem transport into the listerial cell. Despite the fact that it does not synthesize siderophores, L. monocytogenes transports ferric siderophores in the wild environment by the actions of cytoplasmic membrane ABC-transporter systems. The bacterium acquires haem, on the other hand, by two mechanisms. At low (nanomolar) concentrations, sortase B-dependent, peptidoglycan-anchored proteins scavenge the iron porphyrin in human or animal tissues, and transfer it to the underlying ABC-transporters in the cytoplasmic membrane for uptake. At concentrations at or above 50 nM, however, haem transport becomes sortase-independent, and occurs by direct interactions of the iron porphyrin with the same ABC-transporter complexes. The architecture of the Gram-positive cell envelope plays a fundamental role in these mechanisms, and the haem acquisition abilities of L. monocytogenes are an element of its ability to cause infectious disease.
单核细胞增生李斯特菌是李斯特菌病的病原体，是一种具有致病性的食源革兰氏阳性细菌病原体，死亡率为20%-30%。它具有广泛的铁转运能力，既可以以铁载体的形式转运铁，也可以从哺乳动物铁结合蛋白中提取铁。在本综述中，我们重点关注铁载体和血红素转运到李斯特菌细胞内的机制。尽管单核细胞增生李斯特菌不合成铁载体，但在野生环境中，它通过细胞质膜ABC转运系统的作用来转运铁载体。另一方面，该细菌通过两种机制获取血红素。在低（纳摩尔）浓度下，分选酶B依赖性、肽聚糖锚定蛋白会清除人或动物组织中的铁卟啉，并将其转移到细胞质膜中潜在的ABC转运蛋白上以供摄取。然而，在浓度达到或高于50 nM时，血红素转运变得不依赖分选酶，而是通过铁卟啉与相同的ABC转运蛋白复合物直接相互作用来发生。革兰氏阳性菌细胞壁的结构在这些机制中起着重要作用，单核细胞增生李斯特菌获取血红素的能力是其导致传染病能力的一个因素。
