Identification and Molecular Analysis oflbpBA, Which Encodes the Two-Component Meningococcal Lactoferrin Receptor

Abstract

We identified lbpB, encoding the lipoprotein component of the meningococcal lactoferrin receptor. An LbpB mutant was unable to acquire Fe from lactoferrin and exhibits decreased surface binding to lactoferrin. Primer extension and reverse transcription-PCR analysis indicate that lbpB and lbpA are cotranscribed on a polycistronic Fe-repressible mRNA.

Identification and Functional Characterization of the Neisseria gonorrhoeae lbpB Gene Product

“…Conclusions. We cloned an N. gonorrhoeae lbpB gene, providing genetic evidence for the existence of a second LF receptor protein in the gonococcus, similar to that described recently for meningococci (6,20,28). Despite difficulties encountered in isolating the 5Ј end of the gonococcal lbpB gene, we succeeded in isolating a clone (pUNCH192SB) with an intact 5Ј end of lbpB.…”

“…A receptor for LF, LbpA, was identified and the corresponding lbpA gene was cloned and characterized in N. gonorrhoeae (3) and N. meningitidis (29). Recently, a second LF receptor protein, LbpB, was identified in N. meningitidis (6,20,28). Here we report the cloning of lbpB from N. gonorrhoeae and characterization of the role of LbpB in gonococcal LF binding and Fe acquisition.…”

“…These data suggested that LbpB was a lipoprotein. Based on fluorographic analysis and palmitic acid labeling, Lewis et al concluded that LbpB in N. meningitidis is a lipoprotein (20). LbpB was 31% identical to TbpB of the same gonococcal strain and 81% identical to the recently reported meningococcal LbpB (6,28).…”

Cloning and functional characterization of Neisseria gonorrhoeae tonB, exbB and exbD genes

“…The TF receptor is composed of the 100 kDa transmembrane protein, Tbp1, and the 85 kDa lipoprotein, Tbp2, encoded by the genes tbpA and tbpB, respectively (Schryvers and Morris, 1988a;Cornelissen et al, 1992;Legrain et al, 1993;Anderson et al, 1994;Cornelissen and Sparling, 1994;Cornelissen and Sparling, 1996). The LF receptor is composed of the 103 kDa transmembrane protein Lbp1 and a lipoprotein, Lbp2, analogous to Tbp2 encoded by the genes lbpA and lbpB, respectively (Schryvers and Morris, 1988b;Pettersson et al, 1993;1994a,b;Biswas and Sparling, 1995;Bonnah et al, 1995;Lewis et al, 1996;our unpublished observations). Two receptors for HB binding were recently described (HmbR in Neisseria meningitidis by Stojiljkovic et al, 1995, and HpuB in N. meningitidis and Neisseria gonorrhoeae by Dyer, 1995 andChen et al, 1996).…”

Interactions of haemoglobin with the Neisseria meningitidis receptor HpuAB: the role of TonB and an intact proton motive force

“…There are currently no known homologues of HpuA in the public databases. In the structurally analogous Tf and Lf receptors, the lipoprotein is surface exposed and is not required for receptor function, playing an accessory role in ligand specificity and binding (Cornelissen and Sparling, 1996;Bonnah and Schryvers, 1998;Lewis et al, 1998b;Pettersson et al, 1998). In contrast, isogenic single mutants of meningococcal and gonococcal HpuAB suggested that both receptor components are required for the binding and utilization of Hb or HbHp (Chen et al, 1998;Lewis et al, 1999).…”