Expression of a functional neisserial fbp gene in Escherichia coli

The ability to acquire iron from a human host is a major determinant in the pathogenesis of Neisseria gonorrhoeae and Neisseria meningitidis. Pathogenic Neisseria spp. do not synthesize siderophores and instead express a receptor-mediated, high-affinity iron acquisition system in the iron-restricted environment of its host. A ferric-iron-binding protein (Fbp) of Neisseria spp. is also iron-regulated and may play a central role in this novel iron-uptake system. To define the physical properties of Fbp further, we used polymerase chain reaction to synthesize DNA fragments containing the fbp structural gene with and without the sequence encoding the Fbp leader peptide. These fragments were ligated into pUC13 to create in-frame fusions with the alpha peptide of lacZ. The expression of Fbp was under the control of the lacZ promoter. Both fusion clones produced Fbp in large amounts, facilitating the purification of quantities of Fbp sufficient for elucidating the biochemical, immunologic, and functional properties of this protein.