High Resolution Structure of an Alternate Form of the Ferric Ion Binding Protein from Haemophilus influenzae

Shouldice, Stephen R.; Dougan, D.R.; Skene, R.J.; Tari, Leslie W.; McRee, Duncan E.; Yu, Rong-hua; Schryvers, Anthony B.

doi:10.1074/jbc.m211780200

Cited by 40 publications

(38 citation statements)

References 34 publications

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“…The amino acid sequence of E. canis Fbp also maintains a basic amino acid at Lys14 that aligns with the important His9 of Fbp's from N. gonorrhoeae and H. influenzae (12). The crystal structure of M. haemolytica Fbp predicted an octahedral means of iron coordination involving eight amino acids (34) (11,12,33,34), which allowed modeling of the primary sequence of E. canis Fbp against these crystal structures by using SWISS-MODEL. The model predicts that the E. canis Fbp exhibits the characteristic two-domain structure connected by a hinge region of antiparallel ␤-strands, as seen in the Fbp's, similar to the lobes of mammalian transferrin (12,27) (Fig.…”

Section: Resultsmentioning

confidence: 99%

An Immunoreactive 38-Kilodalton Protein of Ehrlichia canis Shares Structural Homology and Iron-Binding Capacity with the Ferric Ion-Binding Protein Family

Doyle¹,

Zhang²,

Popov³

et al. 2005

Infect Immun

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Ehrlichiae are tick-transmitted, gram-negative, obligately intracellular bacteria that live and replicate in cytoplasmic vacuoles, but little is known about iron acquisition mechanisms necessary for their survival. In this study, a genus-conserved immunoreactive ferric ion-binding protein (Fbp) of Ehrlichia canis was identified and its iron-binding capability was investigated. E. canis Fbp was homologous to a family of periplasmic Fbp's involved in iron acquisition and transport in gram-negative bacteria. E. canis Fbp had a molecular mass (38 kDa) consistent with those of Fbp's in other bacteria and exhibited substantial immunoreactivity in its native conformation. The predicted three-dimensional structure of E. canis Fbp demonstrated conservation of important Fbp family structural motifs: two domains linked with a polypeptide "hinge" region. Under ironbinding conditions, the recombinant Fbp exhibited an intense red color and an absorbance spectrum indicative of iron binding, and it bound Fe(III) but not Fe(II). Fbp was observed primarily in the cytoplasm of the reticulate forms of E. canis and Ehrlichia chaffeensis but was notably found on extracellular morula fibers in morulae containing dense-cored organisms. Although expression of Fbp is regulated through an operon of three functionally linked genes in other gram-negative bacteria, the absence of an intact fbp operon in Ehrlichia spp. suggests that genes involved in ehrlichial iron acquisition have been subject to reductive evolution.

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Section: Resultsmentioning

confidence: 99%

An Immunoreactive 38-Kilodalton Protein of Ehrlichia canis Shares Structural Homology and Iron-Binding Capacity with the Ferric Ion-Binding Protein Family

Doyle¹,

Zhang²,

Popov³

et al. 2005

Infect Immun

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“…SDS-PAGE analysis of proteins was performed using standard methods; proteins were visualized by staining with Coomassie blue dye. Extracts enriched in B. pertussis periplasmic proteins were produced by the osmotic shock method described by Shouldice and coworkers (79). Cell proteins for immunoblot analysis were prepared from B. pertussis strain Tohama I and B. bronchiseptica strains RB50 and RB54 cultured in iron-replete and iron-depleted SS media.…”

Section: Methodsmentioning

confidence: 99%

Transcriptional Profiling of the Iron Starvation Response in Bordetella pertussis Provides New Insights into Siderophore Utilization and Virulence Gene Expression

et al. 2011

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Serological studies of patients with pertussis and the identification of antigenic Bordetella pertussis proteins support the hypothesis that B. pertussis perceives an iron starvation cue and expresses multiple iron source utilization systems in its natural human host environment. Furthermore, previous studies using a murine respiratory tract infection model showed that several of these B. pertussis iron systems are required for colonization and persistence and are differentially expressed over the course of infection. The present study examined genome-wide changes in B. pertussis gene transcript abundance in response to iron starvation in vitro. In addition to known iron source utilization genes, we identified a previously uncharacterized iron-repressed cytoplasmic membrane transporter system, fbpABC, that is required for the utilization of multiple structurally distinct siderophores including alcaligin, enterobactin, ferrichrome, and desferrioxamine B. Expression of type III secretion system genes was also found to be upregulated during iron starvation in both B. pertussis strain Tohama I and Bordetella bronchiseptica strain RB50. In a survey of type III secretion system protein production by an assortment of B. pertussis laboratory-adapted and low-passage clinical isolate strains, iron limitation increased the production and secretion of the type III secretion system-specific translocation apparatus tip protein Bsp22 in all Bvg-proficient strains. These results indicate that iron starvation in the infected host is an important environmental cue influencing not only Bordetella iron transport gene expression but also the expression of other important virulence-associated genes.

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“…The proteins were expressed, and the periplasmic fraction isolated using a previously described modified osmotic shock procedure (27). The protein preparations were dialyzed extensively against 20 mM ethanolamine buffer, pH 9.0, at 4°C and subjected to anion exchange chromatography as a final purification step.…”

Section: Methodsmentioning

confidence: 99%

Novel Anion-independent Iron Coordination by Members of a Third Class of Bacterial Periplasmic Ferric Ion-binding Proteins

Shouldice

McRee²,

Dougan³

et al. 2005

Journal of Biological Chemistry

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The uptake of the element iron is vital for the survival of most organisms. Numerous pathogenic Gram-negative bacteria utilize a periplasm-to-cytosol ATP-binding cassette transport pathway to transport this essential atom in to the cell. In this study, we investigated the Yersinia enterocolitica (YfuA) and Serratia marcescens (SfuA) iron-binding periplasmic proteins. We have determined the 1.8-Å structures of iron-loaded (YfuA) and iron-free (SfuA) forms of this class of proteins. Although the sequence of these proteins varies considerably from the other members of the transferrin structural superfamily, they adopt the same three-dimensional fold. The iron-loaded YfuA structure illustrates the unique nature of this new class of proteins in that they are able to octahedrally coordinate the ferric ion in the absence of a bound anion. The iron-free SfuA structure contains a bound citrate anion in the iron-binding cleft that tethers the N-and C-terminal domains of the apo protein and stabilizes the partially open structure.

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High Resolution Structure of an Alternate Form of the Ferric Ion Binding Protein from Haemophilus influenzae

Cited by 40 publications

References 34 publications

An Immunoreactive 38-Kilodalton Protein of Ehrlichia canis Shares Structural Homology and Iron-Binding Capacity with the Ferric Ion-Binding Protein Family

An Immunoreactive 38-Kilodalton Protein of Ehrlichia canis Shares Structural Homology and Iron-Binding Capacity with the Ferric Ion-Binding Protein Family

Transcriptional Profiling of the Iron Starvation Response in Bordetella pertussis Provides New Insights into Siderophore Utilization and Virulence Gene Expression

Novel Anion-independent Iron Coordination by Members of a Third Class of Bacterial Periplasmic Ferric Ion-binding Proteins

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