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'Ma, L and Payne, SM (2012) AhpC is required for optimal production of enterobactin by Escherichia coli. J. Bacteriol. '

The Escherichia coli alkyl hydroperoxide reductase subunit C (AhpC) is a peroxiredoxin that detoxifies peroxides. Here, we show an additional role for AhpC in cellular iron metabolism of E. coli. Deletion of ahpC resulted in reduced growth and reduced accumulation of iron by cells grown in low iron media. Liquid chromatography - mass spectroscopy (LC-MS) analysis of culture supernatants showed that the ahpC mutant secreted much less enterobactin, the siderophore that chelates and transports ferric iron under iron-limiting conditions, than the wild type E. coli. The ahpC mutant produced less 2,3-dihydroxybenzoate, the intermediate in the enterobactin biosynthesis pathway, and providing 2,3-dihydroxybenzoate restored wild type growth of the ahpC mutant. These data indicated that the defect was in an early step in enterobactin biosynthesis, Providing additional copies of entC, which functions in the first dedicated step of enterobactin biosynthesis, but not other enterobactin biosynthesis genes, suppressed the mutant phenotype. Additionally, providing either shikimate or a mixture of para-amino benzoate, tryptophan, tyrosine and phenylalanine, which like enterobactin, are synthesized from the precursor chorismate, also suppressed the mutant phenotype. These data suggested that AhpC affected the activity of EntC or the availability of its substrate chorismate.

PubMed Online version:10.1128/JB.01574-12