Abstract
A gene encoding a putative 2[4Fe–4S] ferredoxin (FdxA) was identified upstream of, and divergent to the peroxide stress defense gene
ahpC of the microaerophilic pathogen
Campylobacter jejuni. The transcription start site of
fdxA was located 27 and 28 bp upstream of the
fdxA start codon. Transcriptional fusions of the
fdxA promoter to a
lacZ reporter gene demonstrated that expression of
fdxA is iron-induced, and thus oppositely regulated to the iron-repressed
ahpC gene. Insertional mutagenesis of the
fdxA gene did not affect microaerobic growth of
C. jejuni, but significantly reduced aerotolerance of
C. jejuni. The
fdxA gene is the first reported iron-induced gene of
C. jejuni, and encodes a novel component of its oxidative stress defense.