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Fur‐Independent Induction of Helicobacter pylori Flavodoxin‐Encoding Gene ( fldA ) Under Iron Starvation
Author(s) -
Kwon Dong H.,
Versalovic James
Publication year - 2009
Publication title -
helicobacter
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.206
H-Index - 79
eISSN - 1523-5378
pISSN - 1083-4389
DOI - 10.1111/j.1523-5378.2009.00669.x
Subject(s) - flavodoxin , biology , gene , helicobacter pylori , open reading frame , microbiology and biotechnology , genetics , sequence analysis , peptide sequence , biochemistry , enzyme , ferredoxin
Background and Aims: Helicobacter pylori infection is associated with a variety of diseases including gastric cancer. Flavodoxin is an electron transfer protein containing a flavin mononucleotide prosthetic group and substituted an iron‐containing electron transfer protein under iron‐limiting conditions. H. pylori flavodoxin has been reported but its pathogenic role is unclear. The aim of this study is to understand a pathogenic role of H. pylori flavodoxin under iron‐limiting condition. Methods: The flavodoxin‐encoding gene ( fldA ) was cloned from one of clinical H. pylori isolates (DU17) and its transcript was quantified by primer extension, Northern hybridization, and real‐time polymerase chain reaction in different concentrations of an iron chelator. The fldA transcript was also quantified in H. pylori ATCC 700392, lacking a ferric uptake regulatory (fur) protein. Result: Nucleotide sequence of the fldA from H. pylori DU17 revealed a 492‐bp (164 amino acids) open reading frame with a deduced amino acid sequence having 97% identity to that from the complete genomic sequence of H. pylori 26695. The deduced promoter [–35, –10, and +1] of the fldA was 56‐bp upstream from the first codon of FldA. The fldA transcript (~0.55‐kb) was induced up to 14‐fold in both wild‐type and fur ‐knocked‐out strains under iron‐limiting conditions, suggesting that the fldA induction is independent to the Fur protein. Conclusion: The fldA gene may play an important role in iron starvation conditions.