Transferrin Binding Protein B and Transferrin Binding Protein A2 Expand the Transferrin Recognition Range of Histophilus somni

ABSTRACT The bacterial bipartite transferrin receptor is an iron acquisition system that several important human and animal pathogens require for survival. It consists of the TonB-dependent transporter transferrin binding protein A (TbpA) and the surface lipoprotein transferrin binding protein B (TbpB). Curiously, the Tbps are only found in host-specific pathogens and are themselves host specific, meaning that they will bind to the transferrin of their host species but not to the transferrins of other animal species. While this phenomenon has long been established, neither the steps in the evolutionary process that led to this exquisite adaptation for the host nor the steps that could alter it are known. We sought to gain insight into these processes by studying Tbp specificity in Histophilus somni, an economically important pathogen of cattle. A past study showed that whole cells of H. somni specifically bind bovine transferrin but not transferrin from sheep and goats, two bovids whose transferrins share 93% amino acid sequence identity with bovine transferrin. To our surprise, we found that H. somni can use sheep and goat transferrins as iron sources for growth and that HsTbpB, but not HsTbpA, has detectable affinity for sheep and goat transferrins. Furthermore, a third transferrin binding protein found in H. somni, HsTbpA2, also showed affinity for sheep and goat transferrins. Our results suggest that H. somni TbpB and TbpA2 may contribute to broadening the host transferrin recognition range of H. somni. IMPORTANCE Host-restricted pathogens infect a single host species or a narrow range of host species. Histophilus somni, a pathogen that incurs severe economic losses for the cattle industry, infects cattle, sheep, and goats but not other mammals. The transferrin binding proteins, TbpA and TbpB, are thought to be a key iron acquisition system in H. somni; however, despite their importance, H. somni TbpA and TbpB were previously shown to be cattle transferrin specific. In our study, we find that H. somni TbpB and another little-studied Tbp, TbpA2, bind sheep and goat transferrins, as well as bovine transferrin. Our results suggest that TbpB and TbpA2 may allow for host range expansion and provide a mechanism for how host specificity in Tbp-encoding pathogens can be altered.

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Transferrin binding protein B and Transferrin binding protein A 2 expand the transferrin recognition range of Histophilus somni

10.1101/730739 ◽

2019 ◽

Author(s):

Anastassia K. Pogoutse ◽

Trevor F. Moraes

Keyword(s):

Host Species ◽

Binding Protein ◽

Iron Acquisition ◽

Protein A ◽

Acquisition System ◽

Sheep And Goats ◽

Iron Acquisition System ◽

Histophilus Somni ◽

Bovine Transferrin ◽

Protein B

AbstractThe bacterial bipartite transferrin receptor is an iron acquisition system that is required for survival by several key human and animal pathogens. It consists of the TonB-dependent transporter Transferrin binding protein A (TbpA) and the surface lipoprotein Transferrin binding protein B (TbpB). Curiously, the Tbps are only found in host specific pathogens, and are themselves host specific, meaning that they will bind to the transferrin of their host species, but not to those of other animal species. While this phenomenon has long been established, neither the steps in the evolutionary process that led to this exquisite adaptation for the host, nor the steps that could alter it, are known. We sought to gain insight into these processes by studying Tbp specificity in Histophilus somni, a major pathogen of cattle. A past study showed that whole cells of H. somni specifically bind bovine transferrin, but not transferrin from sheep and goats, two bovids whose transferrins share 93% amino acid sequence identity with bovine transferrin. To our surprise, we found that H. somni can use sheep and goat transferrins as iron sources for growth, and that HsTbpB, but not HsTbpA, has detectable affinity for sheep and goat transferrins. Furthermore, a third transferrin binding protein, HsTbpA2, also showed affinity for sheep and goat transferrins. Our results show that H. somni TbpB and TbpA2 act to broaden the host transferrin recognition range of H. somni.ImportanceHost restricted pathogens infect a single host species or a narrow range of host species. Histophilus somni, a pathogen that incurs severe economic losses for the cattle industry, infects cattle, sheep, and goats, but not other mammals. The transferrin binding proteins, TbpA and TbpB, are thought to be a key iron acquisition system in H. somni, however, surprisingly, they were also shown to be cattle transferrin-specific. In our study we find that H. somni TbpB, and another little-studied Tbp, TbpA2, bind sheep and goat transferrins as well as bovine transferrin. Our results suggest that TbpA2 may have allowed for host range expansion, and provide a mechanism for how host specificity in Tbp containing pathogens can be altered.

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Nonbinding Site-Directed Mutants of Transferrin Binding Protein B Exhibit Enhanced Immunogenicity and Protective Capabilities

Infection and Immunity ◽

10.1128/iai.02572-14 ◽

2014 ◽

Vol 83 (3) ◽

pp. 1030-1038 ◽

Cited By ~ 31

Author(s):

Rafael Frandoloso ◽

Sonia Martínez-Martínez ◽

Charles Calmettes ◽

Jamie Fegan ◽

Estela Costa ◽

...

Keyword(s):

Immune Response ◽

Binding Protein ◽

Iron Acquisition ◽

Critical Role ◽

T Cell Response ◽

Content Type ◽

Growth And Survival ◽

Mutant Proteins ◽

Protein B

Host-adapted Gram-negative bacterial pathogens from thePasteurellaceae,Neisseriaceae, andMoraxellaceaefamilies normally reside in the upper respiratory or genitourinary tracts of their hosts and rely on utilizing iron from host transferrin (Tf) for growth and survival. The surface receptor proteins that mediate this critical iron acquisition pathway have been proposed as ideal vaccine targets due to the critical role that they play in survival and disease pathogenesisin vivo. In particular, the surface lipoprotein component of the receptor, Tf binding protein B (TbpB), had received considerable attention as a potential antigen for vaccines in humans and food production animals but this has not translated into the series of successful vaccine products originally envisioned. Preliminary immunization experiments suggesting that host Tf could interfere with development of the immune response prompted us to directly address this question with site-directed mutant proteins defective in binding Tf. Site-directed mutants with dramatically reduced binding of porcine transferrin and nearly identical structure to the native proteins were prepared. A mutantHaemophilus parasuisTbpB was shown to induce an enhanced B-cell and T-cell response in pigs relative to native TbpB and provide superior protection from infection than the native TbpB or a commercial vaccine product. The results indicate that binding of host transferrin modulates the development of the immune response against TbpBs and that strategies designed to reduce or eliminate binding can be used to generate superior antigens for vaccines.

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Siderophore-Mediated Iron Acquisition Enhances Resistance to Oxidative and Aromatic Compound Stress inCupriavidus necatorJMP134

Applied and Environmental Microbiology ◽

10.1128/aem.01938-18 ◽

2018 ◽

Vol 85 (1) ◽

Cited By ~ 5

Author(s):

Changfu Li ◽

Lingfang Zhu ◽

Damin Pan ◽

Shuyu Li ◽

He Xiao ◽

...

Keyword(s):

Gene Cluster ◽

Aromatic Compound ◽

Stress Resistance ◽

Biofilm Formation ◽

Iron Uptake ◽

Iron Acquisition ◽

Acquisition System ◽

Content Type ◽

Swimming Motility ◽

Iron Acquisition System

ABSTRACTMany bacteria secrete siderophores to enhance iron uptake under iron-restricted conditions. In this study, we found thatCupriavidus necatorJMP134, a well-known aromatic pollutant-degrading bacterium, produces an unknown carboxylate-type siderophore named cupriabactin to overcome iron limitation. Using genome mining, targeted mutagenesis, and biochemical analysis, we discovered an operon containing six open reading frames (cubA–F) in theC. necatorJMP134 genome that encodes proteins required for the biosynthesis and uptake of cupriabactin. As the dominant siderophore ofC. necatorJMP134, cupriabactin promotes the growth ofC. necatorJMP134 under iron-limited conditions via enhanced ferric iron uptake. Furthermore, we demonstrated that the iron concentration-dependent expression of thecuboperon is mediated by the ferric uptake regulator (Fur). Physiological analyses revealed that the cupriabactin-mediated iron acquisition system influences swimming motility, biofilm formation, and resistance to oxidative and aromatic compound stress inC. necatorJMP134. In conclusion, we identified a carboxylate-type siderophore named cupriabactin, which plays important roles in iron scavenging, bacterial motility, biofilm formation, and stress resistance.IMPORTANCESince siderophores have been widely exploited for agricultural, environmental, and medical applications, the identification and characterization of new siderophores from different habitats and organisms will have great beneficial applications. Here, we identified a novel siderophore-producing gene cluster inC. necatorJMP134. This gene cluster produces a previously unknown carboxylate siderophore, cupriabactin. Physiological analyses revealed that the cupriabactin-mediated iron acquisition system influences swimming motility, biofilm formation, and oxidative stress resistance. Most notably, this system also plays important roles in increasing the resistance ofC. necatorJMP134 to stress caused by aromatic compounds, which provide a promising strategy to engineer more efficient approaches to degrade aromatic pollutants.

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Rapid evolution of a bacterial iron acquisition system

Molecular Microbiology ◽

10.1111/mmi.13918 ◽

2018 ◽

Vol 108 (1) ◽

pp. 90-100 ◽

Cited By ~ 10

Author(s):

Anushila Chatterjee ◽

Mark R. O'Brian

Keyword(s):

Iron Acquisition ◽

Rapid Evolution ◽

Acquisition System ◽

Iron Acquisition System

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Author Correction: Iron acquisition system of Sphingobium sp. strain SYK-6, a degrader of lignin-derived aromatic compounds

Scientific Reports ◽

10.1038/s41598-020-73843-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Masaya Fujita ◽

Taichi Sakumoto ◽

Kenta Tanatani ◽

HongYang Yu ◽

Kosuke Mori ◽

...

Keyword(s):

Aromatic Compounds ◽

Iron Acquisition ◽

Acquisition System ◽

Iron Acquisition System

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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Regulation of the Expression of Iron-acquisition System Genes in Pathogenic Vibrio Species

YAKUGAKU ZASSHI ◽

10.1248/yakushi.16-00192 ◽

2016 ◽

Vol 136 (11) ◽

pp. 1525-1532 ◽

Cited By ~ 1

Author(s):

Tomotaka Tanabe

Keyword(s):

Iron Acquisition ◽

Acquisition System ◽

Iron Acquisition System

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Crystal structure of the N-lobe of lactoferrin binding protein B from Moraxella bovis1 1This paper is an invited article as a result of a presentation at the International Lactoferrin Conference held in Mazatlan, Mexico (May 2011), and has undergone the Journal’s usual peer review process.

Biochemistry and Cell Biology ◽

10.1139/o11-078 ◽

2012 ◽

Vol 90 (3) ◽

pp. 351-361 ◽

Cited By ~ 7

Author(s):

Elena Arutyunova ◽

Cory L. Brooks ◽

Amanda Beddek ◽

Michelle W. Mak ◽

Anthony B. Schryvers ◽

...

Keyword(s):

Crystal Structure ◽

Structural Information ◽

Peer Review Process ◽

Binding Protein ◽

Iron Acquisition ◽

Protein A ◽

Bacterial Surface ◽

Moraxella Bovis ◽

Surface Receptor ◽

Protein B

Lactoferrin (Lf) is a bi-lobed, iron-binding protein found on mucosal surfaces and at sites of inflammation. Gram-negative pathogens from the Neisseriaceae and Moraxellaceae families are capable of using Lf as a source of iron for growth through a process mediated by a bacterial surface receptor that directly binds host Lf. This receptor consists of an integral outer membrane protein, lactoferrin binding protein A (LbpA), and a surface lipoprotein, lactoferrin binding protein B (LbpB). The N-lobe of the homologous transferrin binding protein B, TbpB, has been shown to facilitate transferrin binding in the process of iron acquisition. Currently there is little known about the role of LbpB in iron acquisition or how Lf interacts with the bacterial receptor proteins. No structural information on any LbpB or domain is available. In this study, we express and purify from Escherichia coli the full-length LbpB and the N-lobe of LbpB from the bovine pathogen Moraxella bovis for crystallization trials. We demonstrate that M. bovis LbpB binds to bovine but not human Lf. We also report the crystal structure of the N-terminal lobe of LbpB from M. bovis and compare it with the published structures of TbpB to speculate on the process of Lf mediated iron acquisition.

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Improvement of Immunogenicity of Meningococcal Lipooligosaccharide by Coformulation with Lipidated Transferrin-Binding Protein B in Liposomes: Implications for Vaccine Development

Clinical and Vaccine Immunology ◽

10.1128/cvi.05683-11 ◽

2012 ◽

Vol 19 (5) ◽

pp. 711-722 ◽

Cited By ~ 3

Author(s):

Noëlle Mistretta ◽

Bruno Guy ◽

Yves Bérard ◽

François Dalençon ◽

Olivia Fratantonio ◽

...

Keyword(s):

Vaccine Development ◽

Binding Protein ◽

Hek293 Cells ◽

Molar Ratio ◽

Adjuvant Effect ◽

Content Type ◽

Endotoxic Activity ◽

Protein B

ABSTRACTAmong various meningococcal antigens, lipooligosaccharide (LOS) and recombinant lipidated transferrin-binding protein B (rlip-TbpB) are considered to be putative vaccine candidates against group BNeisseria meningitidis. In the present work, we report the development of a new liposome-based vaccine formulation containing both rlip-TbpB and L8 LOS. The endotoxic activity of the liposomal LOS was evaluatedin vitrousing theLimulusAmebocyte Lysate assay and compared to the endotoxic activity of free LOS. Above a 250:1 lipid/LOS molar ratio, liposomes were shown to effectively detoxify the LOS as the endotoxic activity of the LOS was reduced by more than 99%. Immunogenicity studies in rabbits showed that the presence of rlip-TbpB dramatically increased the immunogenicity of the LOS. While the formulation raised a strong anti-TbpB response, it elicited a higher anti-LOS IgG level than the liposomal LOS alone. Sera from rabbits immunized with rlip-TbpB/liposomal LOS displayed increased ability to recognize LOS on live bacteria expressing the L8 immunotype and increased anti-LOS-specific bactericidal activity compared to sera from rabbits immunized with liposomal LOS alone. Measurement of interleukin-8 (IL-8) produced by HEK293 cells transfected with Toll-like receptor (TLR) after stimulation with rlip-TbpB showed that the protein is a TLR2 agonist, which is in accordance with the structure of its lipid. Furthermore, anin vivostudy demonstrated that the lipid moiety is not only required for its adjuvant effect but also has to be linked to the protein. Overall, the rlip-TbpB/LOS liposomal formulation was demonstrated to induce an effective anti-LOS response due to the adjuvant effect of rlip-TbpB on LOS.

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