The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Ming-chung Chang - One of the best experts on this subject based on the ideXlab platform.
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Ferrous Iron-Binding Protein Omb of Salmonella enterica serovar Choleraesuis promotes resistance to hydrophobic antibiotics and contributes to its virulence.
Microbiology, 2009Co-Authors: Yin-ching Chung, Hsin-chun Lee, I-cheng Tseng, Ming-chung ChangAbstract:Salmonella enterica serovar Choleraesuis (SC) is an important enteric pathogen that causes serious systemic infections in swine and humans. To identify the genes required for resistance to antimicrobial peptides, we constructed a bank of SC transposon mutants and screened them for hypersensitivity to the cationic peptide polymyxin B. Here we report one isolated polymyxin B-susceptible mutant that also exhibited increased sensitivity toward human neutrophil peptide alpha-defensin 1 (HNP-1) and hydrophobic antibiotics including erythromycin and novobiocin. The mutant had a mutation in an ORF identified as outer membrane β-barrel Protein gene omb. The purified recombinant Omb Protein was characterized as a ferrous Iron-Binding Protein. The constructed omb isogenic mutant grew more slowly in Iron-limiting conditions than the wild-type (WT) parent strain. In addition, compared with the WT strain, the omb mutant exhibited an increase in net negative charge upon the cell surface and was more easily killed by polymyxin B, HNP-1 and hydrophobic antibiotics. The omb gene was transcribed, regardless of the Iron content within the growth medium, and the Omb Protein appeared exclusively in the outer membrane fraction. Infection experiments demonstrated virulence attenuation when the mutant was administered orally or intraperitoneally to mice. This study indicates that Omb is a previously unrecognized ferrous Iron-Binding Protein. In vivo, Omb may be involved in the acquisition of ferrous Iron during the initial stages of SC infection and appears to be an important virulence factor for SC in mice.
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Ferrous Iron-Binding Protein Omb of Salmonella enterica serovar Choleraesuis promotes resistance to hydrophobic antibiotics and contributes to its virulence.
Microbiology (Reading England), 2009Co-Authors: Yin-ching Chung, Hsin-chun Lee, I-cheng Tseng, Ming-chung ChangAbstract:Salmonella enterica serovar Choleraesuis (SC) is an important enteric pathogen that causes serious systemic infections in swine and humans. To identify the genes required for resistance to antimicrobial peptides, we constructed a bank of SC transposon mutants and screened them for hypersensitivity to the cationic peptide polymyxin B. Here we report one isolated polymyxin B-susceptible mutant that also exhibited increased sensitivity toward human neutrophil peptide alpha-defensin 1 (HNP-1) and hydrophobic antibiotics including erythromycin and novobiocin. The mutant had a mutation in an ORF identified as outer membrane beta-barrel Protein gene omb. The purified recombinant Omb Protein was characterized as a ferrous Iron-Binding Protein. The constructed omb isogenic mutant grew more slowly in Iron-limiting conditions than the wild-type (WT) parent strain. In addition, compared with the WT strain, the omb mutant exhibited an increase in net negative charge upon the cell surface and was more easily killed by polymyxin B, HNP-1 and hydrophobic antibiotics. The omb gene was transcribed, regardless of the Iron content within the growth medium, and the Omb Protein appeared exclusively in the outer membrane fraction. Infection experiments demonstrated virulence attenuation when the mutant was administered orally or intraperitoneally to mice. This study indicates that Omb is a previously unrecognized ferrous Iron-Binding Protein. In vivo, Omb may be involved in the acquisition of ferrous Iron during the initial stages of SC infection and appears to be an important virulence factor for SC in mice.
Douglas B Kell - One of the best experts on this subject based on the ideXlab platform.
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the biology of lactoferrin an Iron Binding Protein that can help defend against viruses and bacteria
Frontiers in Immunology, 2020Co-Authors: Douglas B Kell, Eugene L Heyden, Etheresia PretoriusAbstract:Lactoferrin is a nutrient classically found in mammalian milk. It binds Iron and is transferred via a variety of receptors into and between cells, serum, bile, and cerebrospinal fluid. It has important immunological properties, and is both antibacterial and antiviral. In particular, there is evidence that it can bind to at least some of the receptors used by coronaviruses and thereby block their entry. Of importance are Heparan Sulfate Proteoglycans (HSPGs) and the host receptor angiotensin-converting enzyme 2 (ACE2), as based on other activities lactoferrin might prevent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from attaching to the host cells. Lactoferrin (and more specifically enteric-coated LF because of increased bioavailability) may consequently be of preventive and therapeutic value during the present COVID-19 pandemic.
Timothy A. Mietzner - One of the best experts on this subject based on the ideXlab platform.
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Coordination of Iron by the Ferric Iron-Binding Protein of Pathogenic Neisseria Is Homologous to the Transferrins
Biochemistry, 1994Co-Authors: Andrew J. Nowalk, Sarah Burroughs Tencza, Timothy A. MietznerAbstract:The ferric Iron-Binding Protein (Fbp) functions as a periplasmic-Binding Protein in the high-affinity active transport of growth-essential Iron by pathogenic Neisseria. Fbp reversibly binds a single ferric ion per molecule of Protein with high affinity. Similarly, the transferrins are a highly conserved family of bilobed vertebrate Proteins that reversibly bind a single molecule of Iron on each of the N- and C-terminal lobes. While evolutionarily divergent, Iron Binding by all described transferrin lobes is accomplished by a remarkably similar repertoire of residues, including two Tyr, one His, and one Asp, as well as a synergestic bicarbonate anion. With a molecular mass of ca. 34 kDa, Fbp approximates the size of a transferrin lobe. Given the similarities in Iron-Binding properties, it was investigated whether Fbp bound Iron by a similar molecular strategy as the transferrins. The studies reported here demonstrate that the spectral properties of purified Fbp and human transferrin are similar in the visible range. Chemical modification of purified Fbp in the presence and absence of Iron using the Tyr-specific modifier tetranitromethane demonstrates that between two and three Tyr residues are implicated in Iron Binding. A similar experiment using the His-specific reagent diethyl pyrocarbonate indicates that one of the six Fbp-encoded His residues is protected by Iron. In addition, like the transferrins, a bicarbonate anion is required for the efficient coordination of Iron by Fbp. The range of metals bound by Fbp and human transferrin, including the luminescent lanthanide terbium, is identical. Finally, terbium derivatives of Fbp and human transferrin yield virtually identical luminescence excitation spectra, implying a highly similar Binding site envIronment. These studies suggest that the prokaryotic Fbp is a mono-sited analog for Iron Binding by the eukaryotic transferrins.
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The ferric Iron‐Binding Protein of pathogenic Neisseria spp. functions as a periplasmic transport Protein in Iron acquisition from human transferrin
Molecular microbiology, 1993Co-Authors: Cheng-yen Chen, Sally A. Berish, Stephen A. Morse, Timothy A. MietznerAbstract:The ferric Iron-Binding Protein (Fbp) expressed by pathogenic Neisseria spp. has been proposed to play a central role in the high-affinity acquisition of Iron from human transferrin. The results of this investigation provide evidence that Fbp participates in this process as a functional analogue of a Gram-negative periplasmic-Binding Protein component, which operates as a part of a general active transport process for the receptor-mediated, high-affinity transport of Iron from human transferrin. Known properties of Fbp are correlated with those of other well-characterized periplasmic-Binding Proteins, including structural features and the reversible Binding of ligand. Predictive of a periplasmic-Binding Protein, which functions in the high-affinity acquisition of Iron, is that Fbp is a transient participant in the process of Iron acquisition from human transferrin. Evidence for this is demonstrated by results of pulse-chase experiments. Taken together, the data described here and elsewhere suggest that pathogenic Neisseria spp. use a periplasmic-Binding Protein-mediated active transport mechanism for the acquisition of Iron from human transferrin.
Yin-ching Chung - One of the best experts on this subject based on the ideXlab platform.
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Ferrous Iron-Binding Protein Omb of Salmonella enterica serovar Choleraesuis promotes resistance to hydrophobic antibiotics and contributes to its virulence.
Microbiology, 2009Co-Authors: Yin-ching Chung, Hsin-chun Lee, I-cheng Tseng, Ming-chung ChangAbstract:Salmonella enterica serovar Choleraesuis (SC) is an important enteric pathogen that causes serious systemic infections in swine and humans. To identify the genes required for resistance to antimicrobial peptides, we constructed a bank of SC transposon mutants and screened them for hypersensitivity to the cationic peptide polymyxin B. Here we report one isolated polymyxin B-susceptible mutant that also exhibited increased sensitivity toward human neutrophil peptide alpha-defensin 1 (HNP-1) and hydrophobic antibiotics including erythromycin and novobiocin. The mutant had a mutation in an ORF identified as outer membrane β-barrel Protein gene omb. The purified recombinant Omb Protein was characterized as a ferrous Iron-Binding Protein. The constructed omb isogenic mutant grew more slowly in Iron-limiting conditions than the wild-type (WT) parent strain. In addition, compared with the WT strain, the omb mutant exhibited an increase in net negative charge upon the cell surface and was more easily killed by polymyxin B, HNP-1 and hydrophobic antibiotics. The omb gene was transcribed, regardless of the Iron content within the growth medium, and the Omb Protein appeared exclusively in the outer membrane fraction. Infection experiments demonstrated virulence attenuation when the mutant was administered orally or intraperitoneally to mice. This study indicates that Omb is a previously unrecognized ferrous Iron-Binding Protein. In vivo, Omb may be involved in the acquisition of ferrous Iron during the initial stages of SC infection and appears to be an important virulence factor for SC in mice.
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Ferrous Iron-Binding Protein Omb of Salmonella enterica serovar Choleraesuis promotes resistance to hydrophobic antibiotics and contributes to its virulence.
Microbiology (Reading England), 2009Co-Authors: Yin-ching Chung, Hsin-chun Lee, I-cheng Tseng, Ming-chung ChangAbstract:Salmonella enterica serovar Choleraesuis (SC) is an important enteric pathogen that causes serious systemic infections in swine and humans. To identify the genes required for resistance to antimicrobial peptides, we constructed a bank of SC transposon mutants and screened them for hypersensitivity to the cationic peptide polymyxin B. Here we report one isolated polymyxin B-susceptible mutant that also exhibited increased sensitivity toward human neutrophil peptide alpha-defensin 1 (HNP-1) and hydrophobic antibiotics including erythromycin and novobiocin. The mutant had a mutation in an ORF identified as outer membrane beta-barrel Protein gene omb. The purified recombinant Omb Protein was characterized as a ferrous Iron-Binding Protein. The constructed omb isogenic mutant grew more slowly in Iron-limiting conditions than the wild-type (WT) parent strain. In addition, compared with the WT strain, the omb mutant exhibited an increase in net negative charge upon the cell surface and was more easily killed by polymyxin B, HNP-1 and hydrophobic antibiotics. The omb gene was transcribed, regardless of the Iron content within the growth medium, and the Omb Protein appeared exclusively in the outer membrane fraction. Infection experiments demonstrated virulence attenuation when the mutant was administered orally or intraperitoneally to mice. This study indicates that Omb is a previously unrecognized ferrous Iron-Binding Protein. In vivo, Omb may be involved in the acquisition of ferrous Iron during the initial stages of SC infection and appears to be an important virulence factor for SC in mice.
Rikio Tokunaga - One of the best experts on this subject based on the ideXlab platform.
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Ribosomal Protein P2, a novel Iron-Binding Protein
Archives of Biochemistry and Biophysics, 1992Co-Authors: Takako Furukawa, T. Uchiumi, Rikio Tokunaga, Shigeru TaketaniAbstract:Abstract We examined the properties of a new Iron-Binding Protein purified previously from rat liver ( T. Furukawa, S. Taketani, H. Kohno, and R. Tokunaga, 1991 , Biochem. Biophys. Res. Commun. 181, 409–415). The Protein was digested with trypsin and the peptides were analyzed by reverse-phase high-performance liquid chromatography. The partial amino acid sequences of the tryptic peptides coincided with that of rat ribosomal Protein P2. Immunoblot analysis and Iron-Binding assay confirmed that the Iron-Binding Protein and ribosomal Protein P2 are identical. Then the Iron Binding ability of ribosomal Protein P2 was examined in rat hepatoma H4IIEC3 cells incubated with radioactive Iron. When immunoprecipitation with anti-Iron-Binding Protein serum was performed using cells incubated with 59 Fe-citrate, about 4% of the 59 Fe radioactivity in cells was associated with the Iron-Binding Protein through 30 to 90 min of incubation. About 1.5% of radioactive Iron in cells incubated with 59 Fe-transferrin was found in immunoprecipitates with anti-Iron-Binding Protein serum during 1 to 5 h of incubation, and 4 to 7% of the radioactivity was found in immunoprecipitates with a monoclonal antibody against ribosomal P Proteins in the same incubation. These results demonstrate that ribosomal Proteins P2 binds Iron taken up by the cells.
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A newly identified Iron-Binding Protein in rat liver: purification and characterization.
Biochemical and biophysical research communications, 1991Co-Authors: Takako Furukawa, Shigeru Taketani, Hirao Kohno, Rikio TokunagaAbstract:A novel Iron-Binding Protein from rat liver homogenates was purified 1,800-fold with a 5.7 % yield, to apparent homogeneity. The molecular weight of the Protein was estimated to be 16,000, by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The purified Protein exhibited 0.43 mol of Iron Binding per mol of Protein with a dissociation constant (Kd) of 3.5 × 10 −6 M. Al 3+ inhibited the Iron-Binding and the Binding was also slightly inhibited by Ni 2+ . Other divalent metal ions such as Cu 2+ , Zn 2+ and Mn 2+ were without effect. Immunoblot analysis of the Iron-Binding Protein revealed that the Protein is located mainly in microsomes. This newly identified Iron-Binding Protein may be involved in intracellular transport of Iron.