Identification of alcA, a Bordetella bronchiseptica gene necessary for alcaligin production

The alcA gene, essential for the production of the dihydroxamate siderophore, alcaligin, by Bordetella bronchiseptica, was cloned and sequenced. The alcA gene was identified on a 4.7-kb EcoRI genomic fragment adjacent to a Tn5lac transposon insertion that inactivated alcaligin production in strain MBORD846. Analysis of the alcA nucleotide sequence revealed a putative Fur-binding site, suggesting that expression of this gene is repressed by iron. The deduced aminoacid sequence of this open reading frame had significant homology with the Escherichia coli iucD gene product, an enzyme required for biosynthesis of the dihydroxamate siderophore aerobactin.