Gonococcal transferrin-binding protein 2 facilitates but is not essential for transferrin utilization

Anderson, John M.; Sparling, P. Frederick; Cornelissen, Cynthia Nau

doi:10.1128/jb.176.11.3162-3170.1994

Cited by 181 publications

(232 citation statements)

References 49 publications

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“…gonorrboeae (Anderson et al, 1994). The absence of obvious promoter sequences in the 85 bp intercistronic region upstream of the Neisseria t b p A gene (Legrain e t al., 1993;Cornelissen e t al., 1992) suggested that the two genes might be transcribed from a single promoter ; this was confirmed by elimination of t b p A expression upon insertional mutagenesis in the tbpB gene with an C2 fragment (Anderson et al, 1994). The short 13 bp intercistronic region between the tbp genes in A .…”

Section: Discussionmentioning

confidence: 99%

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Sequence, genetic analysis, and expression of Actinobacillus pleuropneumoniae transferrin receptor genes

Gonzalez

Rosteck

et al. 1995

Microbiology

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The tbpA and *pi? genes encoding the transferrin receptor proteins T b p l and Tbp2 from a serotype 7 strain of Actinobacillus pleuropneumoniae were cloned, sequenced, and expressed in Escherichia coli. The tbpB gene was preceded by putative promoter and regulatory sequences and was separated from the downstream tbpA gene by a 13 bp intercistronic sequence suggesting that the two genes may be coordinately transcribed. Determination of the nucleotide sequence of this region facilitated PCR amplification of the tbp region from a serotype 1 strain for comparative purposes. The deduced amino acid sequences of the T b p l proteins had regions of homology with Neisseria Lbp and Tbpls and with TonB-dependent outer membrane (OM) receptors of E. coli. The deduced amino acid sequences of the Tbp2 proteins were nearly identical to those presented in previous studies. Upon high-level expression of the tbpA gene, a large proportion of the recombinant T b p l was found in inclusion bodies and could not be aff inity-isolated with immobilized porcine transferrin. Most of the remaining expressed T b p l was present in the OM fraction, was expressed at the surface of E. coli cells, and retained binding activity that was specific for the Globe of porcine transferrin. Although recombinant Tbp2 was found in inclusion bodies during high-level expression, a significant proportion was associated with a novel OM fraction that appeared in sucrose density gradients which was distinct from the OM fraction containing recombinant Tbpl. The recombinant Tbp2 was accessible at the surface yet was unable to bind porcine transferrin. In contrast to previous observations, the binding by recombinant Tbp2 was specific for the Globe of porcine transferrin. These results indicate that the A. pleuropneumoniae transferrin receptor proteins have similar properties to the receptor proteins in Neisseria spp. and Haemophilus influenzae, and that functional studies performed with recombinant receptor proteins need to consider differences in processing and export of these proteins when expressed in heterologous hosts.

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Section: Discussionmentioning

confidence: 99%

“…It is likely that tbp genes are regulated by Fur since putative Fur boxes have been identified upstream of the tbpB gene in N. meningitidis (Legrain e t al., 1993), N . gonorrboeae (Anderson et al, 1994), H. injuenqae (Gray-Owen et al, 1995) and, based on the results of the present study, A.…”

Section: Discussionmentioning

confidence: 99%

Sequence, genetic analysis, and expression of Actinobacillus pleuropneumoniae transferrin receptor genes

Gonzalez

Rosteck

et al. 1995

Microbiology

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“…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).…”

Section: Introductionmentioning

confidence: 99%

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

Biswas

Anderson

Sparling

1997

Molecular Microbiology

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SummaryNeisseria gonorrhoeae is able to utilize iron (Fe) from a variety of sources including transferrin (TF) and lactoferrin (LF). To gain insight into the molecular mechanisms used by gonococci to scavenge Fe from TF and LF, we cloned a 3.5 kb segment of wild-type DNA that repaired the defect in tlu mutants, which are unable to take up Fe from either TF or LF despite exhibiting apparently normal ligand binding to the receptor. Nucleotide sequence determination identified three open reading frames (ORFs), designated ORF1, ORF2, and ORF3, which were arranged in tandem. The deduced amino acid sequence of the 852 bp ORF1 encoded a 28 kDa protein that exhibited 26-32% identity with TonB proteins of nine other bacteria. The 663 bp ORF2 predicted a 24 kDa protein and the 435 bp long ORF3 predicted a 15 kDa protein. These predicted protein sequences exhibited 32-38% and 24-36% identity, respectively, with ExbB and ExbD proteins of three other bacteria. Thus, the sequence comparison identified the ORF1, ORF2 and ORF3 as gonococcal homologues of the E. coli tonB, exbB and exbD genes. An insertional mutation in the tonB homologue resulted in the failure of gonococci to grow with TF, LF or human haemoglobin (HB) as sole Fe sources and in the inability to take up 55 Fe from TF and LF. The tonB mutation did not prevent the utilization of Fe from citrate (CT) or haemin (HM). Binding of TF, LF and HB to whole cells in a solid-phase binding assay was largely unaffected by the tonB mutation. We conclude that the pathways for utilization of Fe bound to TF, LF and HB but not to HM or CT were dependent on the TonB system.

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“…We focused our efforts on two Tbp-specific domains, the NB domain from TbpB and the L2 domain from TbpA based largely on surface exposure and strain-to-strain sequence conservation. Though TbpB is considered to be fully surface exposed [42,43], we demonstrated L2 surface exposure by flow cytometric analysis. Because we utilized fixed instead of live cells in our surface binding studies, it is possible surface accessibility of the L2 domain by L2 antisera was due to non-native conformations of surface TbpA molecules [44].…”

Section: Discussionmentioning

confidence: 92%

Gonococcal transferrin binding protein chimeras induce bactericidal and growth inhibitory antibodies in mice

Price

Masri

Hollander

et al. 2007

Vaccine

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We have previously demonstrated the full-length gonococcal transferrin binding proteins (TbpA and TbpB) to be promising antigens in the development of a protective vaccine against Neisseria gonorrhoeae. In the current study we employed a genetic chimera approach fusing domains from TbpA and TbpB to the A2 domain of cholera toxin, which naturally binds in a non-covalent fashion to the B subunit of cholera toxin during assembly. For one construct, the N-terminal half of TbpB (NB) was fused to the A2 subunit of cholera toxin. In a second construct, the loop 2 region (L2) of TbpA was genetically fused between the NB domain and the A2 domain, generating a double chimera. Both chimeras were immunogenic and induced serum bactericidal and vaginal growthinhibiting antibodies. This study highlights the potential of using protective epitopes instead of fulllength proteins in the development of an efficacious gonococcal vaccine.

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Gonococcal transferrin-binding protein 2 facilitates but is not essential for transferrin utilization

Abstract: Pathogenic Neisseria species have been shown to scavenge iron from transferrin (Ti)

Cited by 181 publications

References 49 publications

Sequence, genetic analysis, and expression of Actinobacillus pleuropneumoniae transferrin receptor genes

Sequence, genetic analysis, and expression of Actinobacillus pleuropneumoniae transferrin receptor genes

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

Gonococcal transferrin binding protein chimeras induce bactericidal and growth inhibitory antibodies in mice

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