Both the full‐length and the N‐terminal domain of the meningococcal transferrin‐binding protein B discriminate between human iron‐loaded and apo‐transferrin

We have readdressed the ability of the transferrin-binding protein B (TbpB) from Neisseria meningitidis to discriminate between the iron-loaded and the iron-free human transferrin (hTf) by using the BIAcore technology, a powerful experimental technique for the observation of direct interactions between a receptor and its ligands, without the use of labels. Recombinant full-length TbpB from five N. meningitidis strains were produced and purified from Escherichia coli as fusion proteins. They showed a preference for the binding to iron-loaded hTf. As for the full-length molecule, we have demonstrated that the minimal N-terminal hTf binding domain of meningococcal TbpB from B16B6 and M982 strains was able to discriminate between both hTf forms.