The bacterial receptor protein, transferrin-binding protein B, does not independently facilitate the release of metal ion from human transferrin

2003 ◽  
Vol 81 (4) ◽  
pp. 275-283 ◽  
Author(s):  
Ulyana Nemish ◽  
Rong-Hua Yu ◽  
Leslie W Tari ◽  
Karla Krewulak ◽  
Anthony B Schryvers
Keyword(s):  
Outer Membrane ◽  
Metal Binding ◽  
Metal Ion ◽  
Binding Protein ◽  
Protein A ◽  
Nitrilotriacetic Acid ◽  
Receptor Protein ◽  
Binding Studies ◽  
Metal Ion Removal ◽  
Protein B

Pathogenic Gram-negative bacteria of the Pasteurellaceae and Neisseriaceae acquire iron for growth from host transferrin through the action of specific surface receptors. Iron is removed from transferrin by the receptor at the cell surface and is transported across the outer membrane to the periplasm. A periplasmic binding protein-dependent pathway subsequently transports iron into the cell. The transferrin receptor is composed of a largely surface-exposed lipoprotein, transferrin binding protein B, and a TonB-dependent integral outer membrane protein, transferrin binding protein A. To examine the role of transferrin binding protein B in the iron removal process, complexes of recombinant transferrin binding protein B and transferrin were prepared and compared with transferrin in metal-binding and -removal experiments. A polyhistidine-tagged form of recombinant transferrin binding protein B was able to purify a complex with transferrin that was largely monodisperse by dynamic light scattering analysis. Gallium was used instead of iron in the metal-binding studies, since it resulted in increased stability of recombinant transferrin binding protein B in the complex. Difference absorption spectra were used to monitor removal of gallium by nitrilotriacetic acid. Kinetic and equilibrium binding studies indicated that transferrin binds gallium more tightly in the presence of transferrin binding protein B. Thus, transferrin binding protein B does not facilitate metal ion removal and additional components are required for this process.Key words: iron, transport, outer membrane, lipoprotein, glycoprotein.

scholarly journals Metal-binding studies for a de novo designed calcium-binding protein

2002 ◽  
Vol 15 (7) ◽  
pp. 571-574 ◽  
Author(s):  
Anna L. Wilkins ◽  
Yiming Ye ◽  
Wei Yang ◽  
Hsiau-Wei Lee ◽  
Zhi-ren Liu ◽  
...  
Keyword(s):  
Metal Binding ◽  
Calcium Binding ◽  
De Novo ◽  
Binding Protein ◽  
Calcium Binding Protein ◽  
Binding Studies

scholarly journals Purification and properties of a 23 kDa Ca2+-binding protein from Drosophila melanogaster

1990 ◽  
Vol 271 (3) ◽  
pp. 661-666 ◽  
Author(s):  
L E Kelly
Keyword(s):  
Binding Proteins ◽  
Binding Protein ◽  
Protein A ◽  
Mammalian Brain ◽  
Binding Studies ◽  
Mobility Shift ◽  
Western Blots ◽  
Heat Stable ◽  
Drosophila Protein ◽  
Sheep Brain

Recent reports have shown that there exists in mammalian brain a number of heat-stable Ca2(+)-binding proteins that are distinct from calmodulin [McDonald & Walsh (1985) Biochem. J. 232, 559-567]. We have attempted to characterize equivalent Ca2(+)-binding proteins from Drosophila. Affigel-phenothiazine chromatography, which can be used to purify calmodulin and other Ca2(+)-binding proteins, allowed the identification of a possible heat-stable 23 kDa Ca2(+)-binding protein. A purification procedure for this protein has been devised. Purified 23 kDa protein shows characteristics typical of a Ca2(+)-binding protein; there is a mobility shift on SDS/polyacrylamide gels in the presence of EGTA, and Western blotting, followed by the use of the 45Ca2+ overlay technique, confirms that the 23 kDa protein does bind Ca2+. 45Ca2+ binding studies indicate that this protein binds 1 mol of Ca2+/mol of protein, with Kd 1.9 microM. A single band with pI 5.2 is obtained on isoelectric focusing. Analysis of Western blots of Drosophila tissues probed with antibodies to the Ca2(+)-binding protein indicates that it has a widespread distribution, but is absent from muscle tissue. The antibodies also cross-react with a protein of identical molecular mass in extracts of sheep brain. The possible similarity between this Drosophila Ca2(+)-binding protein and mammalian proteins is discussed, and comparison is made between this Drosophila protein and other Ca2(+)-binding proteins purified from vertebrates.

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.

2012 ◽  
Vol 90 (3) ◽  
pp. 351-361 ◽  
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.

scholarly journals Lactoferrin binding protein B – a bi-functional bacterial receptor protein

2017 ◽  
Vol 13 (3) ◽  
pp. e1006244 ◽  
Author(s):  
Nicholas K. H. Ostan ◽  
Rong-Hua Yu ◽  
Dixon Ng ◽  
Christine Chieh-Lin Lai ◽  
Anastassia K. Pogoutse ◽  
...  
Keyword(s):  
Binding Protein ◽  
Receptor Protein ◽  
Protein B

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

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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