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Huang Y, Li Z, Wu Y, Li Y, Pramod S, Chen G, Zhu W, Zhang Z, Wang H, Lin H. Comparative analysis of allergenicity and predicted linear epitopes in α and β parvalbumin from turbot (Scophthalmus maximus). JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2023; 103:2313-2324. [PMID: 36606403 DOI: 10.1002/jsfa.12432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 12/19/2022] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND Parvalbumin (PV) can be subdivided into two phylogenetic lineages, αPV and βPV. The bony fish βPV is considered a major fish allergen. However, there is no available report on the immunological property and epitope mapping of bony fish αPV. RESULTS To characterize the allergenic property of bony fish αPV and investigate the difference in allergenic property of bony fish αPV and βPV, turbot (Scophthalmus maximus) αPV and βPV were identified by mass spectrometry and were expressed in Escherichia coli system in this study. Spectra analysis and three-dimensional (3D) modeling showed the similar structure between αPV and βPV. However, αPV exhibited lower immunoglobulin E/immunoglobulin G (IgE/IgG) binding capacity than βPV. Three identified βPV epitopes possessed higher IgE reactivity and more hydrophobic residues than three identified αPV epitopes. In addition, less similarity in sequence homology of αPV epitopes was observed with allergen sequences in database. CONCLUSION These finding expanded information on fish PV epitopes and substantiated the difference in allergenicity and epitope mapping between fish αPV and βPV, which will improve the epitope-based detection tools of PV and diagnostic of PV induced fish allergy. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Yuhao Huang
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
| | - Zhenxing Li
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
| | - Yeting Wu
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
| | - Yonghong Li
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
- Department of Research and Development, HOB Biotech Group Corp., Ltd, Suzhou, P. R. China
| | - Siddanakoppalu Pramod
- Department of Studies and Research in Biochemistry, Davangere University, Davangere, India
| | - Guanzhi Chen
- Department of Dermatology, Affiliated Hospital of Medical College Qingdao University, Qingdao, P. R. China
| | - Wenjia Zhu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, P. R. China
| | - Ziye Zhang
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
| | - Hao Wang
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
| | - Hong Lin
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
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Wai CYY, Leung NYH, Leung ASY, Wong GWK, Leung TF. Seafood Allergy in Asia: Geographical Specificity and Beyond. FRONTIERS IN ALLERGY 2021; 2:676903. [PMID: 35387013 PMCID: PMC8974776 DOI: 10.3389/falgy.2021.676903] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 06/17/2021] [Indexed: 11/13/2022] Open
Abstract
Asian countries have unique ways of food processing and dietary habits that may explain the observed differences in the prevalence, natural history, epidemiology and sensitization pattern of food allergic diseases when compared to western countries. Per capita consumption of seafood, including fish and shellfish, is well above the global average for many Asian countries because of their coastal geographical location and rich seafood supply. The wide availability and high abundance of seafood in Asian countries have shaped a diverse way of processing and eating this major food group. Such unique features have significant impact on the sensitization profile and allergenicity of Asians to fish and shellfish. For example, fish and shellfish are eaten raw in some countries that may promote sensitization to heat-labile allergens not otherwise seen in other regions. Fermented fish sauce is commonly used as a condiment in some countries which may promote fish sensitization. Shrimp head and shrimp roe are regarded as delicacies in some countries, but their allergen profiles are yet to be characterized. Freshwater fish and shellfish are a common food source in many Asian countries but the allergenicity of many such species remains unknown. In this review, we discuss factors that may contribute to differences in molecular profile and sensitization pattern for fish and shellfish that are observed in Asian populations and revisit the current status of seafood allergy in this part of the world. Acknowledging the similarities and differences of seafood allergy patterns between Asian and western populations can help us refine a better strategy for diagnosing and managing seafood allergy.
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Affiliation(s)
- Christine Y. Y. Wai
- Department of Paediatrics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Nicki Y. H. Leung
- Department of Paediatrics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Agnes S. Y. Leung
- Department of Paediatrics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Gary W. K. Wong
- Department of Paediatrics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Ting F. Leung
- Department of Paediatrics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
- Hong Kong Hub of Paediatric Excellence, The Chinese University of Hong Kong, Hong Kong, China
- *Correspondence: Ting F. Leung
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Jeong SG, Kim SH. Application of commercial kits using DNA-based and immunochemical methods for determination of shrimp allergens in kimchi and its ingredients. J Food Sci 2020; 85:3638-3643. [PMID: 32856293 DOI: 10.1111/1750-3841.15320] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/23/2020] [Accepted: 05/11/2020] [Indexed: 11/28/2022]
Abstract
Shrimps cause a significant part of crustacea-related allergies. It is used in processed foods, including fermented Korean foods, such as kimchi. Even low amounts of shrimp allergens can provoke reactions in consumers allergic to shrimp. Accurate food labeling is the most effective means of preventing the consumption of allergenic ingredients. To validate labeling compliance and minimize the risk of cross-contaminations, the effectiveness of methodologies used for the detection of allergens in foods should be compared. Here, seven commercial kits, based on quantitative real-time polymerase chain reaction (PCR) or enzyme-linked immunosorbent assay (ELISA), were assessed for their ability to detect the presence of shrimp allergens in food. Our results showed that SureFood real-time PCR kit and Ridascreen ELISA kit had the highest recovery, whereas five other kits underperformed in the determination of allergen content of kimchi and its ingredients. The variation in recovery among the kits depended on the limit of detection and reactivity to the shrimp allergens, tropomyosin, and sarcoplasmic calcium-binding protein. PRACTICAL APPLICATION: This research confirms the performance of commercial kits to detect the presence of shrimp allergens in kimchi, and demonstrates that the sensitivity of these kits depends on reactivity to the specific shrimp allergenic proteins. These results can be used to food allergy labeling and can be applied by the food industry to develop allergen test kits for fermented foods with improved performance.
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Affiliation(s)
- Seul-Gi Jeong
- Research and Development Division, World Institute of Kimchi, Gwangju, 61755, Republic of Korea
| | - Sung Hyun Kim
- Research and Development Division, World Institute of Kimchi, Gwangju, 61755, Republic of Korea
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Li J, Li Z, Kong D, Li S, Yu Y, Li H. IgE and IgG4 responses to shrimp allergen tropomyosin and its epitopes in patients from coastal areas of northern China. Mol Med Rep 2020; 22:371-379. [PMID: 32319635 PMCID: PMC7248481 DOI: 10.3892/mmr.2020.11084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 03/17/2020] [Indexed: 11/05/2022] Open
Abstract
Sensitization to allergens and their peptides varies among patients due to geographical or ethnic differences. The present study aimed to investigate immunoglobulin (Ig)E and IgG4 responses to tropomyosin and its peptides in shrimp allergic patients from northern China. A total of 92 subjects were studied, including 35 shrimp allergic patients, 29 patients with house dust mite (HDM) and/or cockroach allergic patients and 28 healthy volunteers. Serum IgE and IgG4 antibodies to recombinant shrimp tropomyosin (rPen a 1) and its peptides were measured by means of a light-initiated chemiluminescent assay. A total of 9 major sequential epitopes of Pen a 1 reported in the literature were synthesized. Of 35 shrimp allergic patients, 25 (71.4%) had positive Pen 1-specific IgE (sIgE) antibodies and 22 (62.9%) contained measurable rPen a 1-specific IgG4 (sIgG4) antibodies. A strong IgG4 response accompanied the presence of IgE to Pen a 1. None of the patients with HDM and/or cockroach allergy demonstrated IgE reactivity to rPen a 1. The reaction frequency of IgE binding epitope was 20–48%, while that of IgG4 binding epitope was 63.6–3.9%. The IgE and IgG4 recognition patterns of the tropomyosin peptides demonstrated high interpatient heterogeneity. Diversity of IgE binding epitopes was positively correlated with Pen a 1 sIgE levels. In the study population, tropomyosin was a major allergen recognized by the majority of shrimp allergic patients, which is consistent with previous reports. However, none of the 9 epitopes are major (reaction frequency >50%) IgE-binding regions, indicating the epitopes profile may be different in other regions.
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Affiliation(s)
- Junpu Li
- The Clinical Laboratory of Tianjin Chest Hospital, Tianjin 300222, P.R. China
| | - Zhiwei Li
- Department of Clinical Laboratory, School of Medical Laboratory, Tianjin Medical University, Tianjin 300203, P.R. China
| | - Deyu Kong
- Department of Laboratory Medicine, Tianjin Port Hospital, Tianjin 300456, P.R. China
| | - Shaoshen Li
- Department of Laboratory Medicine, Academy of Traditional Chinese Medicine Affiliated Hospital, Tianjin 300120, P.R. China
| | - Yang Yu
- Department of Clinical Laboratory, School of Medical Laboratory, Tianjin Medical University, Tianjin 300203, P.R. China
| | - Huiqiang Li
- Department of Clinical Laboratory, School of Medical Laboratory, Tianjin Medical University, Tianjin 300203, P.R. China
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Klueber J, Costa J, Randow S, Codreanu‐Morel F, Verhoeckx K, Bindslev‐Jensen C, Ollert M, Hoffmann‐Sommergruber K, Morisset M, Holzhauser T, Kuehn A. Homologous tropomyosins from vertebrate and invertebrate: Recombinant calibrator proteins in functional biological assays for tropomyosin allergenicity assessment of novel animal foods. Clin Exp Allergy 2020; 50:105-116. [PMID: 31541579 PMCID: PMC6973240 DOI: 10.1111/cea.13503] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/29/2019] [Accepted: 09/16/2019] [Indexed: 12/30/2022]
Abstract
BACKGROUND Novel foods may provide new protein sources for a growing world population but entail risks of unexpected food-allergic reactions. No guidance on allergenicity assessment of novel foods exists, while for genetically modified (GM) crops it includes comparison of sequence identity with known allergens, digestibility tests and IgE serum screening. OBJECTIVE As a proof of concept, to evaluate non-/allergenic tropomyosins (TMs) regarding their potential as new calibrator proteins in functional biological in vitro assays for the semi-quantitative allergy risk assessment of novel TM-containing animal foods with mealworm TM as an example. METHODS Purified TMs (shrimp, Penaeus monodon; chicken Gallus gallus; E coli overexpression) were compared by protein sequencing, circular dichroism analysis and in vitro digestion. IgE binding was quantified using shrimp-allergic patients' sera (ELISA). Biological activities were investigated (skin testing; titrated basophil activation tests, BAT), compared to titrated biological mediator release using humanized rat basophil leukaemia (RBL) cells. RESULTS Shrimp and chicken TMs showed high sequence homology, both alpha-helical structures and thermal stability. Shrimp TM was stable during in vitro gastric digestion, chicken TM degraded quickly. Both TMs bound specific IgE from shrimp-allergic patients (significantly higher for shrimp TM), whereas skin reactivity was mostly positive with only shrimp TM. BAT and RBL cell assays were positive with shrimp and chicken TM, although at up to 100- to 1000-times lower allergen concentrations for shrimp than chicken TM. In RBL cell assays using both TM as calibrators, an activation of effector cells by mealworm TM similar to that by shrimp TM confirmed the already reported high allergenic potency of mealworm TM as a novel protein source. CONCLUSIONS & CLINICAL RELEVANCE According to current GM crops' allergenicity assessment, non-allergenic chicken TM could falsely be considered an allergen on a weight-of-evidence approach. However, calibrating allergenic potency in functional BAT and RBL cell assays with clinically validated TMs allowed for semi-quantitative discrimination of novel food protein's allergenicity. With TM calibration as a proof of concept, similar systems of homologous protein might be developed to scale on an axis of allergenicity.
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Affiliation(s)
- Julia Klueber
- Department of Infection and ImmunityLuxembourg Institute of HealthEsch‐sur‐AlzetteLuxembourg
- Department of Dermatology and Allergy CenterOdense Research Center for AnaphylaxisUniversity of Southern DenmarkOdense CDenmark
| | - Joana Costa
- REQUIMTE‐LAQV/Faculdade de Farmácia daUniversidade do PortoPortoPortugal
| | | | | | | | - Carsten Bindslev‐Jensen
- Department of Dermatology and Allergy CenterOdense Research Center for AnaphylaxisUniversity of Southern DenmarkOdense CDenmark
| | - Markus Ollert
- Department of Infection and ImmunityLuxembourg Institute of HealthEsch‐sur‐AlzetteLuxembourg
- Department of Dermatology and Allergy CenterOdense Research Center for AnaphylaxisUniversity of Southern DenmarkOdense CDenmark
| | | | - Martine Morisset
- National Unit of Immunology and AllergologyCentre Hospitalier de LuxembourgLuxembourgLuxembourg
- Present address:
Unité d’AllergologieCHU AngersAngersFrance
| | | | - Annette Kuehn
- Department of Infection and ImmunityLuxembourg Institute of HealthEsch‐sur‐AlzetteLuxembourg
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Folded or Not? Tracking Bet v 1 Conformation in Recombinant Allergen Preparations. PLoS One 2015; 10:e0132956. [PMID: 26186356 PMCID: PMC4506129 DOI: 10.1371/journal.pone.0132956] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/20/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Recombinant Bet v 1a (rBet v 1a) has been used in allergy research for more than three decades, including clinical application of so-called hypoallergens. Quantitative IgE binding to rBet v 1a depends on its native protein conformation, which might be compromised upon heterologous expression, purification, or mutational engineering of rBet v 1a. OBJECTIVE To correlate experimental/theoretical comparisons of IgE binding of defined molar ratios of folded/misfolded recombinant Bet v 1a variants and to determine accuracy and precision of immuno- and physicochemical assays routinely used to assess the quality of recombinant allergen preparations. METHODS rBet v 1a and its misfolded variant rBet v 1aS112P/R145P were heterologously expressed and purified from Escherichia coli. Structural integrities and oligomerisation of the recombinant allergens were evaluated by 1H-nuclear magnetic resonance (1H-NMR), circular dichroism (CD) spectroscopy, and dynamic light scattering (DLS). IgE binding of defined combinations of rBet v 1a and rBet v 1aS112P/R145P was assessed using immunoblotting (IB), enzyme-linked immunosorbent assay (ELISA) and mediator release (MR) of humanized rat basophilic leukemia cells sensitized with serum IgE of subjects allergic to birch pollen. Experimental and theoretically expected results of the analyses were compared. RESULTS 1H-NMR spectra of rBet v 1a and rBet v 1aS112P/R145P demonstrate a native and highly disordered protein conformations, respectively. The CD spectra suggested typical alpha-helical and beta-sheet secondary structure content of rBet v 1a and random coil for rBet v 1aS112P/R145P. The hydrodynamic radii (RH) of 2.49 ± 0.39 nm (rBet v 1a) and 3.1 ± 0.56 nm (rBet v 1aS112P/R145P) showed monomeric dispersion of both allergens in solution. Serum IgE of birch pollen allergic subjects bound to 0.1% rBet v 1a in the presence of 99.9% of non-IgE binding rBet v 1aS112P/R145P. Immunoblot analysis overestimated, whereas ELISA and mediator release assay underestimated the actual quantity of IgE-reactive rBet v 1a in mixtures of rBet v 1a/rBet v 1aS112P/R145P with a molar ratio of rBet v 1a ≤ 10%. CONCLUSION Valid conclusions on quantitative IgE binding of recombinant Bet v 1a preparations depend on the accuracy and precision of physico- and immunochemical assays with which natively folded allergen is detected.
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Enlarging the toolbox for allergen epitope definition with an allergen-type model protein. PLoS One 2014; 9:e111691. [PMID: 25356997 PMCID: PMC4214763 DOI: 10.1371/journal.pone.0111691] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 09/22/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Birch pollen-allergic subjects produce polyclonal cross-reactive IgE antibodies that mediate pollen-associated food allergies. The major allergen Bet v 1 and its homologs in plant foods bind IgE in their native protein conformation. Information on location, number and clinical relevance of IgE epitopes is limited. We addressed the use of an allergen-related protein model to identify amino acids critical for IgE binding of PR-10 allergens. METHOD Norcoclaurine synthase (NCS) from meadow rue is structurally homologous to Bet v 1 but does not bind Bet v 1-reactive IgE. NCS was used as the template for epitope grafting. NCS variants were tested with sera from 70 birch pollen allergic subjects and with monoclonal antibody BV16 reported to compete with IgE binding to Bet v 1. RESULTS We generated an NCS variant (Δ29NCSN57/I58E/D60N/V63P/D68K) harboring an IgE epitope of Bet v 1. Bet v 1-type protein folding of the NCS variant was evaluated by 1H-15N-HSQC NMR spectroscopy. BV16 bound the NCS variant and 71% (50/70 sera) of our study population showed significant IgE binding. We observed IgE and BV16 cross-reactivity to the epitope presented by the NCS variant in a subgroup of Bet v 1-related allergens. Moreover BV16 blocked IgE binding to the NCS variant. Antibody cross-reactivity depended on a defined orientation of amino acids within the Bet v 1-type conformation. CONCLUSION Our system allows the evaluation of patient-specific epitope profiles and will facilitate both the identification of clinically relevant epitopes as biomarkers and the monitoring of therapeutic outcomes to improve diagnosis, prognosis, and therapy of allergies caused by PR-10 proteins.
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Alessandri S, Sancho A, Vieths S, Mills CEN, Wal JM, Shewry PR, Rigby N, Hoffmann-Sommergruber K. High-throughput NMR assessment of the tertiary structure of food allergens. PLoS One 2012; 7:e39785. [PMID: 22768312 PMCID: PMC3388089 DOI: 10.1371/journal.pone.0039785] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 05/30/2012] [Indexed: 11/25/2022] Open
Abstract
Background In vitro component-resolved diagnosis of food allergy requires purified allergens that have to meet high standards of quality. These include the authentication of their conformation, which is relevant for the recognition by specific IgE antibodies from allergic patients. Therefore, highly sensitive and reliable screening methods for the analysis of proteins/allergens are required to assess their structural integrity. In the present study one-dimensional 1H Nuclear Magnetic Resonance (1D 1H-NMR) analysis was adopted for the assessment of overall structural and dynamic properties and authentication of a set of relevant food allergens, including non-specific lipid transfer proteins from apple, peach and hazelnut, 7/8S seed storage globulins from hazelnut and peanut, 11S seed storage globulins from hazelnut and peanut, caseins from cows' and goats' milk and tropomyosin from shrimp. Methodology/Principal Findings Two sets of 1D 1H-NMR experiments, using 700 MHz and 600 MHz instruments at 298 K were carried out to determine the presence and the extent of tertiary structure. Structural similarity among members of the individual allergen families was also assessed and changes under thermal stress investigated. The nuclear magnetic resonance (NMR) results were compared with structural information available either from the literature, Protein Data Bank entries, or derived from molecular models. Conclusions/Significance 1D 1H-NMR analysis of food allergens allowed their classification into molecules with rigid, extended and ordered tertiary structures, molecules without a rigid tertiary structure and molecules which displayed both features. Differences in thermal stability were also detected. In summary, 1D 1H-NMR gives insights into molecular fold of proteins and offers an independent method for assessing structural properties of proteins.
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Affiliation(s)
- Stefano Alessandri
- CERM, Centro di Ricerca di Risonanze Magnetiche and Department of Agricultural Biotechnology, University of Florence, Florence, Italy
| | - Ana Sancho
- Institute of Food Research, Norwich, United Kingdom
| | | | | | - Jean-Michel Wal
- INRA, UR496 Immuno-Allergie Alimentaire, CEA/iBiTeC-S/SPI, CEA de Saclay, Gif sur Yvette, France
| | | | - Neil Rigby
- Institute of Food Research, Norwich, United Kingdom
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Kraus B, Boller K, Reuter A, Schnierle BS. Characterization of the human endogenous retrovirus K Gag protein: identification of protease cleavage sites. Retrovirology 2011; 8:21. [PMID: 21429186 PMCID: PMC3073897 DOI: 10.1186/1742-4690-8-21] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 03/23/2011] [Indexed: 11/16/2022] Open
Abstract
Background Viral genomes of the human endogenous retrovirus K (HERV-K) family are integrated into the human chromosome and are transmitted vertically as Mendelian genes. Although viral particles are released by some transformed cells, they have never been shown to be infectious. In general, gammaretroviruses are produced as immature viral particles by accumulation of the Gag polyproteins at the plasma membrane, which subsequently bud from the cell surface. After release from the cell, Gag is further processed by proteolytic cleavage by the viral protease (PR), which results in morphologically mature particles with condensed cores. The HERV-K Gag polyprotein processing and function has not yet been precisely determined. Results We generated a recombinant poxvirus, encoding the human endogenous retrovirus K consensus gag-pro-pol genes (MVA-HERV-Kcon) and obtained high levels of HERV-K Gag expression. The resulting retroviral particle assembled at the plasma membrane, as is typical for gammaretroviruses; and immature as well as mature retrovirus-like particles (VLPs) were observed around the infected cells. VLPs were purified, concentrated and separated by two-dimensional gel electrophoresis. The HERV-K Gag fragments were identified by mass spectroscopy and N-terminal sequencing which revealed that HERV-K Gag is processed into MA, a short spacer peptide, p15, CA and NC. Conclusion The cleavage sites of HERV-K Gag were mapped and found to be highly conserved among HERV-K genomes. The consensus HERV-K gag gene used in this study is known to support viral, infectivity [1], and thus the cleavage sites that were mapped in this study for all the Gag components are relevant for HERV-K infectivity.
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Affiliation(s)
- Benjamin Kraus
- Paul-Ehrlich-Institut, Paul-Ehrlich-Strasse 51-59, 63225 Langen, Germany
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Löwer M, Weydig C, Metzler D, Reuter A, Starzinski-Powitz A, Wessler S, Schneider G. Prediction of extracellular proteases of the human pathogen Helicobacter pylori reveals proteolytic activity of the Hp1018/19 protein HtrA. PLoS One 2008; 3:e3510. [PMID: 18946507 PMCID: PMC2567035 DOI: 10.1371/journal.pone.0003510] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Accepted: 09/30/2008] [Indexed: 01/13/2023] Open
Abstract
Exported proteases of Helicobacter pylori (H. pylori) are potentially involved in pathogen-associated disorders leading to gastric inflammation and neoplasia. By comprehensive sequence screening of the H. pylori proteome for predicted secreted proteases, we retrieved several candidate genes. We detected caseinolytic activities of several such proteases, which are released independently from the H. pylori type IV secretion system encoded by the cag pathogenicity island (cagPAI). Among these, we found the predicted serine protease HtrA (Hp1019), which was previously identified in the bacterial secretome of H. pylori. Importantly, we further found that the H. pylori genes hp1018 and hp1019 represent a single gene likely coding for an exported protein. Here, we directly verified proteolytic activity of HtrA in vitro and identified the HtrA protease in zymograms by mass spectrometry. Overexpressed and purified HtrA exhibited pronounced proteolytic activity, which is inactivated after mutation of Ser205 to alanine in the predicted active center of HtrA. These data demonstrate that H. pylori secretes HtrA as an active protease, which might represent a novel candidate target for therapeutic intervention strategies.
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Affiliation(s)
- Martin Löwer
- Goethe-University, Institute of Cell Biology and Neuroscience / CMP, Frankfurt am Main, Germany
| | | | - Dirk Metzler
- Goethe-University, Institute of Computer Science, Frankfurt am Main, Germany
| | - Andreas Reuter
- Paul-Ehrlich Institute, Department of Allergology, Langen, Germany
| | - Anna Starzinski-Powitz
- Goethe-University, Institute of Cell Biology and Neuroscience / CMP, Frankfurt am Main, Germany
| | - Silja Wessler
- Junior Research Group, Paul-Ehrlich Institute, Langen, Germany
| | - Gisbert Schneider
- Goethe-University, Institute of Cell Biology and Neuroscience / CMP, Frankfurt am Main, Germany
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