The Highly Abundant Protein Ag-lbp55 from Ascaridia galli Represents a Novel Type of Lipid-binding Proteins

Jordanova, Rositsa; Radoslavov, Georgi; Fischer, Peter; Torda, Andrew E.; Lottspeich, Friedrich; Boteva, Raina; Walter, Rolf D.; Bankov, Ilia; Liebau, Eva

doi:10.1074/jbc.m504474200

Cited by 10 publications

(5 citation statements)

References 44 publications

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“…FAR domains do not necessarily occur alone; for example, another unique nematode LBP, Ag-lbp55 from Ascaridia galli, has also been described and contains a C-terminal FAR domain, although its N-terminal part has no known homologues (49). In conclusion we provide the basic structural information for understanding the mode of action of FAR proteins and investigation of inhibitors of lipid binding.…”

Section: Discussionmentioning

confidence: 86%

Fatty Acid- and Retinoid-binding Proteins Have Distinct Binding Pockets for the Two Types of Cargo

Jordanova

Groves

Kostova

et al. 2009

Journal of Biological Chemistry

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Parasitic nematodes cause serious diseases in humans, animals, and plants. They have limited lipid metabolism and are reliant on lipid-binding proteins to acquire these metabolites from their hosts. Several structurally novel families of lipidbinding proteins in nematodes have been described, including the fatty acid-and retinoid-binding protein family (FAR). In Caenorhabditis elegans, used as a model for studying parasitic nematodes, eight C. elegans FAR proteins have been described. The crystal structure of C. elegans FAR-7 is the first structure of a FAR protein, and it exhibits a novel fold. It differs radically from the mammalian fatty acid-binding proteins and has two ligand binding pockets joined by a surface groove. The first can accommodate the aliphatic chain of fatty acids, whereas the second can accommodate the bulkier retinoids. In addition to demonstrating lipid binding by fluorescence spectroscopy, we present evidence that retinol binding is positively regulated by casein kinase II phosphorylation at a conserved site near the bottom of the second pocket. far-7::GFP (green fluorescent protein) expression shows that it is localized in the head hypodermal syncytia and the excretory cell but that this localization changes under starvation conditions. In conclusion, our study provides the basic structural and functional information for investigation of inhibitors of lipid binding by FAR proteins.Hydrophobic lipophilic molecules such as fatty acids, eicosanoids, retinoids, and steroids have important functions both as energy sources and in metabolic signaling. They affect fundamental cellular processes such as gene transcription, cell development, inflammation, and immune response (1-3). The cellular cytosol is hydrophilic, and lipids need to be solubilized and protected from chemical damage. Their transport and availability are tightly regulated. Proteins that coordinate the lipid traffic include lipoproteins (such as the low density lipoprotein) and carrier proteins, known as lipid-binding proteins (LBPs).2 In vertebrates LBPs belong to the ␤-sheet calycin superfamily (lipocalins and fatty acid-binding proteins (FABPs)) or the ␣-helical serum albumin-like superfamily. Nematodes are one of the most abundant groups of multicellular organisms. Parasitic nematodes cause serious and difficult to treat diseases in humans, animals, and plants affecting human health as well as having a negative impact on agricultural economics. It is estimated that more than one-sixth of the earth's population (mainly in developing countries), suffers from nematode infections, and at least 4 of the 15 neglected tropical diseases listed by the World Health Organization are caused by nematodes. Parasitic worms possess limited lipid metabolism and depend on import of essential lipids from their host (4), which makes the lipid transporters good targets for chemoprophylactic treatments. A 14-kDa FABP (Sm14) has been proposed as a vaccine candidate against Schistosoma mansoni in humans and Fasciola hepatica in cattle and sheep (5, ...

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Section: Discussionmentioning

confidence: 86%

Fatty Acid- and Retinoid-binding Proteins Have Distinct Binding Pockets for the Two Types of Cargo

Jordanova

Groves

Kostova

et al. 2009

Journal of Biological Chemistry

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“…By using a solubilisation protocol, we were able to increase the number of potential antigens, especially in the range of 40–220 kDa, to increase the spectrum of measurable worm antibodies, resulting in fewer false negative results. Although the chemical structures of these antigens are not fully known, Jordanova et al [52] described a protein (Ag-Ibp55) with a molecular weight of 55 kDa that represents a novel type of lipid-binding protein and may act as the nematode antigen. Although similar data are not available for H. gallinarum , our results indicate that the chicken host does not differentiate between somatic antigens of both nematodes, and produces similar, if not the same, antibodies that can be quantified with the same assay.…”

Section: Discussionmentioning

confidence: 99%

A comprehensive evaluation of an ELISA for the diagnosis of the two most common ascarids in chickens using plasma or egg yolks

Daş

Hennies²,

Sohnrey

et al. 2017

Parasites Vectors

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BackgroundClassical faecal egg counts (FEC) provide less reliable diagnostic information for nematode infections in chickens. We developed an ELISA based on Ascaridia galli antigens and tested two hypotheses, as follows: (i) IgY antibodies developed against A. galli will also be useful to identify Heterakis gallinarum infections, and (ii) circulating antibodies stored in egg yolks are as good as plasma samples, so a non-invasive diagnosis is possible. The aim of this study, therefore, was to compare the diagnostic accuracy of the ELISA system with FEC, using both plasma and egg yolks from experimentally infected hens. In addition, naturally infected animals were evaluated to validate the assay.ResultsThe assay quantified large differences (P < 0.001) in plasma or in egg-yolk IgY concentrations between infected and uninfected animals in two experiments, each performed with either of the nematode species. The assay performed with high accuracy as quantified with the area under the ROC curve (AUC) values of > 0.90 for both nematodes using either plasma or egg yolks. Sensitivity of the assay was 94 and 93% with plasma and egg yolk samples, respectively, whereas FEC yielded in a sensitivity of 84% in A. galli experiment. Total test accuracy of the assay with plasma samples (AUC = 0.99) tended to be higher (P = 0.0630) than FEC (AUC = 0.92) for A. galli, while the assay with either sample matrix performed similar to FEC (AUC ≥ 0.91) for H. gallinarum. Among the three tests, the FECs correlated better with A. galli burden than the ELISA. Although 90% of naturally infected hens were correctly identified by the ELISA, 45% of the infected hens tested negative with FEC, indicating the validity of the higher test accuracy of the ELISA.ConclusionsAntigens of A. galli can be used successfully to identify H. gallinarum-infected animals, indicating that chickens develop cross-reactive antibodies against the two closely related species. Egg yolks are as informative as plasma samples, so that animal welfare-friendly sampling is possible. Although the assay with plasma samples reveals qualitative information of higher quality than FECs on the infection status of naturally infected birds, the latter is still a better tool to assess the intensity of A. galli but not of H. gallinarum infections.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2121-9) contains supplementary material, which is available to authorized users.

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“…Native Ts -PCHTP was purified from muscle T. spiralis larvae as described for Ag-lbp55 and Ag-NPA-1 [15], [16]. The supernatant after 70% ammonium sulfate precipitation in 20 mM Tris buffer, pH 7.4 was further purified by anion exchange chromatography on DEAE-cellulose.…”

Section: Methodsmentioning

confidence: 99%

“…For light microscopy either anti- Ts -PCHTP serum or monoclonal anti-poly-His antibody (Sigma-Aldrich) were used as a primary antibody at dilutions of 1∶500. Immunolocalization on the light and on the electron microscopical level was performed as described previously [16].…”

Section: Methodsmentioning

confidence: 99%

A Novel Secretory Poly-Cysteine and Histidine-Tailed Metalloprotein (Ts-PCHTP) from Trichinella spiralis (Nematoda)

et al. 2010

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Background Trichinella spiralis is an unusual parasitic intracellular nematode causing dedifferentiation of the host myofiber. Trichinella proteomic analyses have identified proteins that act at the interface between the parasite and the host and are probably important for the infection and pathogenesis. Many parasitic proteins, including a number of metalloproteins are unique for the nematodes and trichinellids and therefore present good targets for future therapeutic developments. Furthermore, detailed information on such proteins and their function in the nematode organism would provide better understanding of the parasite - host interactions.Methodology/Principal FindingsIn this study we report the identification, biochemical characterization and localization of a novel poly-cysteine and histidine-tailed metalloprotein (Ts-PCHTP). The native Ts-PCHTP was purified from T. spiralis muscle larvae that were isolated from infected rats as a model system. The sequence analysis showed no homology with other proteins. Two unique poly-cysteine domains were found in the amino acid sequence of Ts-PCHTP. This protein is also the first reported natural histidine tailed protein. It was suggested that Ts-PCHTP has metal binding properties. Total Reflection X-ray Fluorescence (TXRF) assay revealed that it binds significant concentrations of iron, nickel and zinc at protein:metal ratio of about 1∶2. Immunohistochemical analysis showed that the Ts-PCHTP is localized in the cuticle and in all tissues of the larvae, but that it is not excreted outside the parasite.Conclusions/SignificanceOur data suggest that Ts-PCHTP is the first described member of a novel nematode poly-cysteine protein family and its function could be metal storage and/or transport. Since this protein family is unique for parasites from Superfamily Trichinelloidea its potential applications in diagnostics and treatment could be exploited in future.

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The Highly Abundant Protein Ag-lbp55 from Ascaridia galli Represents a Novel Type of Lipid-binding Proteins

Cited by 10 publications

References 44 publications

Fatty Acid- and Retinoid-binding Proteins Have Distinct Binding Pockets for the Two Types of Cargo

Fatty Acid- and Retinoid-binding Proteins Have Distinct Binding Pockets for the Two Types of Cargo

A comprehensive evaluation of an ELISA for the diagnosis of the two most common ascarids in chickens using plasma or egg yolks

A Novel Secretory Poly-Cysteine and Histidine-Tailed Metalloprotein (Ts-PCHTP) from Trichinella spiralis (Nematoda)

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