Identification and Functional Characterization of the Neisseria gonorrhoeae lbpB Gene Product

We cloned lbpB, encoding a predicted 80-kDa lipoprotein, upstream of lbpA. A nonpolar mutant (LbpB(−) LbpA(+)) had normal lactoferrin (LF) binding and grew normally with LF as an iron source, whereas LbpB(−) LbpA(−) and LbpB(+) LbpA(−) strains had reduced binding of LF and did not grow with LF as an iron source. LbpB bound LF directly in an affinity purification, suggesting that LbpB might play a still-uncharacterized role in the LF iron utilization.