Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
J Biochem. 2010 Apr;147(4):535-43. doi: 10.1093/jb/mvp200. Epub 2009 Dec 2.
Helicobacter pylori is a spiral Gram-negative microaerophilic bacterium. It is unique and distinctive among various bacterial pathogens for its ability to persist in the extreme acidic environment of human stomachs. To address and identify changes in the proteome of H. pylori in response to low pH, we have used a proteomic approach to study the protein expression of H. pylori under neutral (pH 7) and acidic (pH 5) conditions. Global protein-expression profiles of H. pylori under acid stress were analysed by two-dimensional polyacrylamide gel electrophoresis (2-DE) followed by liquid chromatography (LC)-nanoESI-mass spectrometry (MS)/MS and bioinformatics database analysis. Among the proteins differentially expressed under acidic condition, a non-heme iron-containing ferritin of H. pylori (HP-ferritin) was found to be consistently upregulated at pH 5 as compared to pH 7. It was also found that HP-ferritin can switch from an iron-storage protein with ferroxidase activity to a DNA-binding/protection function under in vitro conditions upon exposure to acidic environment. Prokaryotic ferritins, such as non-heme iron-binding HP-ferritin with dual functionality reported herein, may play a significant urease-independent role in the acid adaptation of H. pylori under physiological conditions in vivo.
幽门螺杆菌是一种螺旋形、革兰氏阴性、微需氧细菌。它是各种细菌病原体中独一无二的，因为它能够在人类胃部的极端酸性环境中存活。为了研究幽门螺杆菌在应对低 pH 值时蛋白质组的变化，我们采用蛋白质组学方法研究了中性（pH7）和酸性（pH5）条件下幽门螺杆菌的蛋白质表达。通过二维聚丙烯酰胺凝胶电泳（2-DE）、液相色谱（LC）-纳升电喷雾-质谱（MS）/MS 和生物信息学数据库分析，分析了酸应激下幽门螺杆菌的全蛋白表达谱。在酸性条件下差异表达的蛋白质中，发现一种非血红素铁结合的幽门螺杆菌铁蛋白（HP-铁蛋白）在 pH5 时与 pH7 相比持续上调。还发现，HP-铁蛋白在体外暴露于酸性环境时，可以从具有亚铁氧化酶活性的铁储存蛋白转变为具有 DNA 结合/保护功能。原核铁蛋白，如本文报道的具有双重功能的非血红素铁结合 HP-铁蛋白，可能在生理条件下幽门螺杆菌的酸适应中发挥重要的、与脲酶无关的作用。
