title: Upregulation of a non-heme iron-containing ferritin with dual ferroxidase and DNA-binding activities in Helicobacter pylori under acid stress.
abstract: 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.
authors: Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
authors: Chun-Hao
authors: CH
authors: Huang
authors: I-Liang
authors: IL
authors: Lee
authors: I-Ju
authors: IJ
authors: Yeh
authors: Jiahn-Haur
authors: JH
authors: Liao
authors: Chun-Lun
authors: CL
authors: Ni
authors: Shih-Hsiung
authors: SH
authors: Wu
authors: Shyh-Horng
authors: SH
authors: Chiou
mesh_terms: D000222:Adaptation, Physiological; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D002570:Ceruloplasmin / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D019295:Computational Biology / Q000379:methods; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015536:Down-Regulation; D005293:Ferritins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D020869:Gene Expression Profiling; D005798:Genes, Bacterial; D016480:Helicobacter pylori / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D008832:Microchemistry / Q000379:methods; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011487:Protein Conformation; D040901:Proteomics / Q000379:methods; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological / Q000235:genetics*; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D005293:Ferritins; D002570:Ceruloplasmin