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Rezaei-Moshaei M, Dehestani A, Bandehagh A, Pakdin-Parizi A, Golkar M, Heidari-Japelaghi R. Recombinant pebulin protein, a type 2 ribosome-inactivating protein isolated from dwarf elder (Sambucus ebulus L.) shows anticancer and antifungal activities in vitro. Int J Biol Macromol 2021; 174:352-361. [PMID: 33497693 DOI: 10.1016/j.ijbiomac.2021.01.129] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/11/2021] [Accepted: 01/19/2021] [Indexed: 12/28/2022]
Abstract
In this study, encoding sequence of a new type 2 RIP (pebulin) was isolated and cloned from dwarf elder (Sambucus ebulus L.) native to the northern regions of Iran. The nucleotide sequence of pebulin was ligated to the pET-28a(+) expression plasmid and cloned into the E. coli strain BL21 (DE3) in order to express heterologously of recombinant protein. The recombinant pebulin protein was mainly produced in the form of insoluble inclusion bodies probably because to absence of N-glycosylation process in E. coli. Therefore, in order to increase the expression of recombinant protein in soluble form, co-expression of the target protein with the pG-Tf2 chaperone plasmid and incubation of bacterial culture under low temperature were used to enhance solubility and accumulation of recombinant protein. After purification of the recombinant protein using affinity chromatography method, the bioactivity of pebulin was analyzed by hemagglutination, anticancer, and antifungal assays. The results of the hemagglutination assay showed that purified pebulin agglutinated erythrocytes in all human blood groups. In addition, pebulin considerably inhibited the proliferation of cancer cell lines MCF-7 and HT-29 in a time- and dose-dependent manner and indicated remarkably growth-inhibiting effect against the plant pathogenic fungi such as Alternaria solani and Fusarium oxysporum.
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Affiliation(s)
| | - Ali Dehestani
- Genetics and Agricultural Biotechnology Institute of Tabarestan, Sari Agricultural Sciences and Natural Resources University, Sari, Iran.
| | - Ali Bandehagh
- Department of Plant Breeding and Biotechnology, the University of Tabriz, Tabriz, Iran
| | - Ali Pakdin-Parizi
- Genetics and Agricultural Biotechnology Institute of Tabarestan, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
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Bolognesi A, Bortolotti M, Maiello S, Battelli MG, Polito L. Ribosome-Inactivating Proteins from Plants: A Historical Overview. Molecules 2016; 21:molecules21121627. [PMID: 27898041 PMCID: PMC6273060 DOI: 10.3390/molecules21121627] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 12/12/2022] Open
Abstract
This review provides a historical overview of the research on plant ribosome-inactivating proteins (RIPs), starting from the first studies at the end of eighteenth century involving the purification of abrin and ricin, as well as the immunological experiments of Paul Erlich. Interest in these plant toxins was revived in 1970 by the observation of their anticancer activity, which has given rise to a large amount of research contributing to the development of various scientific fields. Biochemistry analyses succeeded in identifying the enzymatic activity of RIPs and allowed for a better understanding of the ribosomal machinery. Studies on RIP/cell interactions were able to detail the endocytosis and intracellular routing of ricin, thus increasing our knowledge of how cells handle exogenous proteins. The identification of new RIPs and the finding that most RIPs are single-chain polypeptides, together with their genetic sequencing, has aided in the development of new phylogenetic theories. Overall, the biological properties of these proteins, including their abortifacient, anticancer, antiviral and neurotoxic activities, suggest that RIPs could be utilized in agriculture and in many biomedical fields, including clinical drug development.
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Affiliation(s)
- Andrea Bolognesi
- Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Alma Mater Studiorum, University of Bologna, Via San Giacomo 14, 40126 Bologna, Italy.
| | - Massimo Bortolotti
- Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Alma Mater Studiorum, University of Bologna, Via San Giacomo 14, 40126 Bologna, Italy.
| | - Stefania Maiello
- Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Alma Mater Studiorum, University of Bologna, Via San Giacomo 14, 40126 Bologna, Italy.
| | - Maria Giulia Battelli
- Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Alma Mater Studiorum, University of Bologna, Via San Giacomo 14, 40126 Bologna, Italy.
| | - Letizia Polito
- Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Alma Mater Studiorum, University of Bologna, Via San Giacomo 14, 40126 Bologna, Italy.
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Shang C, Chen Q, Dell A, Haslam SM, De Vos WH, Van Damme EJM. The Cytotoxicity of Elderberry Ribosome-Inactivating Proteins Is Not Solely Determined by Their Protein Translation Inhibition Activity. PLoS One 2015; 10:e0132389. [PMID: 26148207 PMCID: PMC4493096 DOI: 10.1371/journal.pone.0132389] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 06/13/2015] [Indexed: 11/18/2022] Open
Abstract
Although the protein translation inhibition activity of ribosome inactivating proteins (RIPs) is well documented, little is known about the contribution of the lectin chain to the biological activity of these proteins. In this study, we compared the in vitro and intracellular activity of several S. nigra (elderberry) RIPs and non-RIP lectins. Our data demonstrate that RIPs from elderberry are much more toxic to HeLa cells than to primary fibroblasts. Differences in the cytotoxicity between the elderberry proteins correlated with differences in glycan specificity of their lectin domain, cellular uptake efficiency and intracellular destination. Despite the fact that the bulk of the RIPs accumulated in the lysosomes and partly in the Golgi apparatus, we could demonstrate effective inhibition of protein synthesis in cellula. As we also observed cytotoxicity for non-RIP lectins, it is clear that the lectin chain triggers additional pathways heralding cell death. Our data suggest that one of these pathways involves the induction of autophagy.
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Affiliation(s)
- Chenjing Shang
- Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Qiushi Chen
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Anne Dell
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Stuart M. Haslam
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Winnok H. De Vos
- Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- Department Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Antwerp, Belgium
| | - Els J. M. Van Damme
- Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Jiménez P, Tejero J, Cordoba-Diaz D, Quinto EJ, Garrosa M, Gayoso MJ, Girbés T. Ebulin from dwarf elder (Sambucus ebulus L.): a mini-review. Toxins (Basel) 2015; 7:648-58. [PMID: 25723322 PMCID: PMC4379516 DOI: 10.3390/toxins7030648] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 01/30/2015] [Accepted: 02/15/2015] [Indexed: 11/16/2022] Open
Abstract
Sambucus ebulus L. (dwarf elder) is a medicinal plant, the usefulness of which also as food is restricted due to its toxicity. In the last few years, both the chemistry and pharmacology of Sambucus ebulus L. have been investigated. Among the structural and functional proteins present in the plant, sugar-binding proteins (lectins) with or without anti-ribosomal activity and single chain ribosome-inactivating proteins (RIPs) have been isolated. RIPs are enzymes (E.C. 3.2.2.22) that display N-glycosidase activity on the 28S rRNA subunit, leading to the inhibition of protein synthesis by arresting the step of polypeptide chain elongation. The biological role of all these proteins is as yet unknown. The evidence suggests that they could be involved in the defense of the plant against predators and viruses or/and a nitrogen store, with an impact on the nutritional characteristics and food safety. In this mini-review we describe all the isoforms of ebulin that have to date been isolated from dwarf elder, as well as their functional characteristics and potential uses, whilst highlighting concern regarding ebulin toxicity.
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Affiliation(s)
- Pilar Jiménez
- Nutrition and Food Science, Faculty of Medicine, and CINAD (Center for Research in Nutrition, Food and Dietetics), University of Valladolid, Valladolid E-47005, Spain.
| | - Jesús Tejero
- Nutrition and Food Science, Faculty of Medicine, and CINAD (Center for Research in Nutrition, Food and Dietetics), University of Valladolid, Valladolid E-47005, Spain.
| | - Damián Cordoba-Diaz
- Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, and IUFI (Institute of Industrial Pharmacy), Complutense University of Madrid, Madrid E-28040, Spain.
| | - Emiliano J Quinto
- Nutrition and Food Science, Faculty of Medicine, and CINAD (Center for Research in Nutrition, Food and Dietetics), University of Valladolid, Valladolid E-47005, Spain.
| | - Manuel Garrosa
- Cell Biology, Histology and Pharmacology, Faculty of Medicine, and INCYL (Institute of Neurosciences of Castile and Leon), University of Valladolid, Valladolid E-47005, Spain.
| | - Manuel J Gayoso
- Cell Biology, Histology and Pharmacology, Faculty of Medicine, and INCYL (Institute of Neurosciences of Castile and Leon), University of Valladolid, Valladolid E-47005, Spain.
| | - Tomás Girbés
- Nutrition and Food Science, Faculty of Medicine, and CINAD (Center for Research in Nutrition, Food and Dietetics), University of Valladolid, Valladolid E-47005, Spain.
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Tejero J, Jiménez P, Quinto EJ, Cordoba-Diaz D, Garrosa M, Cordoba-Diaz M, Gayoso MJ, Girbés T. Elderberries: a source of ribosome-inactivating proteins with lectin activity. Molecules 2015; 20:2364-87. [PMID: 25647575 PMCID: PMC6272206 DOI: 10.3390/molecules20022364] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 01/20/2015] [Accepted: 01/22/2015] [Indexed: 11/16/2022] Open
Abstract
Sambucus (Adoxaceae) species have been used for both food and medicine purposes. Among these, Sambucus nigra L. (black elder), Sambucus ebulus L. (dwarf elder), and Sambucus sieboldiana L. are the most relevant species studied. Their use has been somewhat restricted due to the presence of bioactive proteins or/and low molecular weight compounds whose ingestion could trigger deleterious effects. Over the last few years, the chemical and pharmacological characteristics of Sambucus species have been investigated. Among the proteins present in Sambucus species both type 1, and type 2 ribosome-inactivating proteins (RIPs), and hololectins have been reported. The biological role played by these proteins remains unknown, although they are conjectured to be involved in defending plants against insect predators and viruses. These proteins might have an important impact on the nutritional characteristics and food safety of elderberries. Type 2 RIPs are able to interact with gut cells of insects and mammals triggering a number of specific and mostly unknown cell signals in the gut mucosa that could significantly affect animal physiology. In this paper, we describe all known RIPs that have been isolated to date from Sambucus species, and comment on their antiviral and entomotoxic effects, as well as their potential uses.
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Affiliation(s)
- Jesús Tejero
- Nutrición y Bromatología, Facultad de Medicina and Centro de Investigación en Nutrición, Alimentación y Dietética (CINAD), Universidad de Valladolid, Valladolid 47005, Spain.
| | - Pilar Jiménez
- Nutrición y Bromatología, Facultad de Medicina and Centro de Investigación en Nutrición, Alimentación y Dietética (CINAD), Universidad de Valladolid, Valladolid 47005, Spain.
| | - Emiliano J Quinto
- Nutrición y Bromatología, Facultad de Medicina and Centro de Investigación en Nutrición, Alimentación y Dietética (CINAD), Universidad de Valladolid, Valladolid 47005, Spain.
| | - Damián Cordoba-Diaz
- Farmacia y Tecnología Farmacéutica, Facultad de Farmacia and Instituto Universitario de Farmacia Industrial (IUFI), Universidad Complutense de Madrid, Madrid 28040, Spain.
| | - Manuel Garrosa
- Biología Celular, Histología y Farmacología, Facultad de Medicina and Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Valladolid, Valladolid 47005, Spain.
| | - Manuel Cordoba-Diaz
- Farmacia y Tecnología Farmacéutica, Facultad de Farmacia and Instituto Universitario de Farmacia Industrial (IUFI), Universidad Complutense de Madrid, Madrid 28040, Spain.
| | - Manuel J Gayoso
- Biología Celular, Histología y Farmacología, Facultad de Medicina and Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Valladolid, Valladolid 47005, Spain.
| | - Tomás Girbés
- Nutrición y Bromatología, Facultad de Medicina and Centro de Investigación en Nutrición, Alimentación y Dietética (CINAD), Universidad de Valladolid, Valladolid 47005, Spain.
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Isolation and molecular characterization of two lectins from dwarf elder (Sambucus ebulus L.) blossoms related to the Sam n1 allergen. Toxins (Basel) 2013; 5:1767-79. [PMID: 24129061 PMCID: PMC3813910 DOI: 10.3390/toxins5101767] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 09/16/2013] [Accepted: 09/30/2013] [Indexed: 12/21/2022] Open
Abstract
Sambucus species contain a number of lectins with and without antiribosomal activity. Here, we show that dwarf elder (Sambucus ebulus L.) blossoms express two d-galactose-binding lectins that were isolated and purified by affinity chromatography and gel filtration. These proteins, which we named ebulin blo (A-B toxin) and SELblo (B-B lectin)—blo from blossoms—were subjected to molecular characterization and analysis by MALDI-TOF mass spectrometry and tryptic peptide fingerprinting. Both lectins share a high degree of amino acid sequence homology with Sambucus lectins related to the Sam n1 allergen. Ebulin blo, but not SELblo, was highly toxic by nasal instillation to mice. Overall, our results suggested that both lectins would belong to an allergen family exemplified by Sam n1 and could trigger allergy responses. Furthermore, they raise a concern about ebulin blo toxicity.
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Jiménez P, Gayoso M, Tejero J, Cabrero P, Córdoba-Díaz D, Basterrechea JE, Girbés T. Toxicity in mice of lectin ebulin f present in dwarf Elderberry (Sambucus ebulus L.). Toxicon 2013; 61:26-9. [DOI: 10.1016/j.toxicon.2012.10.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 10/16/2012] [Accepted: 10/18/2012] [Indexed: 10/27/2022]
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Jetzt AE, Cheng JS, Tumer NE, Cohick WS. Ricin A-chain requires c-Jun N-terminal kinase to induce apoptosis in nontransformed epithelial cells. Int J Biochem Cell Biol 2009; 41:2503-10. [PMID: 19695342 PMCID: PMC2783365 DOI: 10.1016/j.biocel.2009.08.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 08/06/2009] [Accepted: 08/07/2009] [Indexed: 10/20/2022]
Abstract
Ricin is a toxin isolated from castor beans that has potential as a weapon of bioterrorism. This glycoprotein consists of an A-chain (RTA) that damages the ribosome and inhibits protein synthesis and a B-chain that plays a role in cellular uptake. Ricin activates the c-Jun N-terminal kinase (JNK) and p38 signaling pathways; however, a role for these pathways in ricin-induced cell death has not been investigated. Our goals were to determine if RTA alone could activate apoptosis and if the JNK and p38 pathways were required for this response. Comparable caspase activation was observed with both ricin and RTA treatment in the immortalized, nontransformed epithelial cell line, MAC-T. Ribosome depurination and inhibition of protein synthesis were induced in 2-4h with 1microg/ml RTA and within 4-6h with 0.1microg/ml RTA. Apoptosis was not observed until 4h of treatment with either RTA concentration. RTA activated JNK and p38 in a time- and concentration-dependent manner that preceded increases in apoptosis. Inhibition of the JNK pathway reduced RTA-induced caspase activation and poly(ADP-ribose) polymerase cleavage. In contrast, inhibition of the p38 pathway had little effect on RTA-induced caspase 3/7 activation. These studies are the first to demonstrate a role for the JNK signaling pathway in ricin-induced cell death. In addition, the MAC-T cell line is shown to be a sensitive in vitro model system for future studies using RTA mutants to determine relationships between RTA-induced depurination, ribotoxic stress, and apoptosis in normal epithelial cells.
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Affiliation(s)
- Amanda E. Jetzt
- Department of Animal Sciences, 59 Dudley Road, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, 08901-8520 USA
- Biotechnology Center for Agriculture and the Environment, 59 Dudley Road, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, 08901-8520 USA
| | - Ju-shun Cheng
- Department of Animal Sciences, 59 Dudley Road, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, 08901-8520 USA
- Biotechnology Center for Agriculture and the Environment, 59 Dudley Road, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, 08901-8520 USA
| | - Nilgun E. Tumer
- Biotechnology Center for Agriculture and the Environment, 59 Dudley Road, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, 08901-8520 USA
| | - Wendie S. Cohick
- Department of Animal Sciences, 59 Dudley Road, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, 08901-8520 USA
- Biotechnology Center for Agriculture and the Environment, 59 Dudley Road, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, 08901-8520 USA
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Citores L, Rojo MA, Jiménez P, Ferreras JM, Iglesias R, Aranguez I, Girbés T. Transient occurrence of an ebulin-related D-galactose-lectin in shoots of Sambucus ebulus L. PHYTOCHEMISTRY 2008; 69:857-864. [PMID: 18068741 DOI: 10.1016/j.phytochem.2007.10.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 10/09/2007] [Accepted: 10/10/2007] [Indexed: 05/25/2023]
Abstract
Young shoots of Sambucus ebulus L. contain a monomeric d-galactose binding lectin (SELlm), which disappears upon shoot development, and was previously undetected since it co-purifies with the non-toxic type 2 ribosome-inactivating protein ebulin l and the dimeric lectin SELld. Molecular cloning of cDNA coding for SELlm and mass spectrometry analysis revealed a protein with a molecular mass of 34,239 Da, which displays 80%, 77% and 45% of amino acid sequence identity with the ebulin l-B chain, SELld and ricin-B chain, respectively. Furthermore, the cloned precursor, with respect to the ebulin l precursor is truncated and contains the signal peptide, a piece of the A chain, a piece of the connecting peptide and the B chain. Further processing yields the lectin protein, which contains only the B chain. Despite the fact that SELlm displays the same d-galactose-binding sites than ricin, it was found that the lectin has different binding properties to D-galactose-containing matrix than ricin. Notably, and unlike ricin, the binding of SELlm and other Sambucus lectins to such matrix was maximum in range of 0-10 degrees C and abolished at 20 degrees C.
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Affiliation(s)
- Lucía Citores
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Valladolid, E-47005 Valladolid, Spain
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Marsden CJ, Knight S, Smith DC, Day PJ, Roberts LM, Phillips GJ, Lord JM. Insertional mutagenesis of ricin A chain: a novel route to an anti-ricin vaccine. Vaccine 2004; 22:2800-5. [PMID: 15246614 DOI: 10.1016/j.vaccine.2004.01.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2003] [Accepted: 01/07/2004] [Indexed: 11/29/2022]
Abstract
The insertion of a specific 25-residue internal peptide into ricin toxin A chain (RTA) reduced the catalytic activity of this protein approximately 300-fold. Directed proteolytic cleavage of the peptide insert essentially restored catalytic activity of the resulting two peptide A chain to normal levels. Ricin holotoxin containing unprocessed mutant A chain was not toxic to cultured mammalian cells, due to enhanced proteasomal degradation, nor was it toxic when injected into rats at a concentration that is lethal in the case of native ricin. Rats treated in this way were completely resistant to native ricin when subsequently challenged with a potentially lethal dose of the toxin. These ricin-resistant animals had a significant anti-ricin antibody titer, indicating that this approach has potential for developing an effective vaccine against this toxin.
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Affiliation(s)
- Catherine J Marsden
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK.
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Spooner R, Watson P, Marsden C, Smith D, Moore K, Cook J, Lord J, Roberts L. Protein disulphide-isomerase reduces ricin to its A and B chains in the endoplasmic reticulum. Biochem J 2004; 383:285-93. [PMID: 15225124 PMCID: PMC1134069 DOI: 10.1042/bj20040742] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Accepted: 06/30/2004] [Indexed: 11/17/2022]
Abstract
Cells expressing ricin B chain within the secretory pathway are significantly more resistant to intoxication by ricin holotoxin but not to other cytotoxins that exploit similar endocytic routes to the cytosol. Furthermore, cells expressing the related B chain of abrin are protected against both incoming abrin and ricin. These phenotypes can be correlated with the abilities of the respective B chains to form disulphide-linked A-B holotoxins, since abrin B chain forms heterodimers with either abrin or ricin A chains, whereas ricin B chain forms heterodimers with ricin A chain only. In the ricin B-expressing cells, this newly made lectin disappears with biphasic kinetics comprising a retention phase followed by slow turnover and disposal after disengagement from calnexin cycle components. Interference with ricin cytotoxicity occurs during the early retention phase when ricin B chain is associated with PDI (protein disulphide-isomerase). The data show that retrotranslocation of incoming toxin is impeded by PDI-catalysed formation of heterodimers between endogenous B and A chains derived from reduced holotoxin, thus proving that reduction of ricin occurs in the endoplasmic reticulum. In contrast with other toxins, ricin does not appear to require either proteolytic cleavage or unfolding for PDI-catalysed reduction.
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Key Words
- endoplasmic reticulum-associated protein degradation (erad)
- oxidoreductase
- protein disulphide-isomerase
- retrograde transport
- ricin
- toxin
- ata, abrin isoform f a chain
- atb, abrin b chain
- bfa, brefeldin a
- bmh, bis-maleimidohexane
- cnx, calnexin
- cst, castanospermine
- cta, cholera toxin a
- dmem, dulbecco's modified eagle's medium
- dmm, deoxymannojirimycin
- dtt, dithiothreitol
- endo h, endoglycosidase h
- er, endoplasmic reticulum
- fcs, foetal calf serum
- nem, n-ethylmaleimide
- pdi, protein disulphide-isomerase
- pe, pseudomonas exotoxin a
- rta, ricin toxin a chain
- rtb, ricin toxin b chain
- sfm, serum-free medium
- slt, shiga-like toxin 1
- tn, tunicamycin
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Affiliation(s)
- Robert A. Spooner
- Molecular Cell Biology, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, U.K
| | - Peter D. Watson
- Molecular Cell Biology, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, U.K
| | - Catherine J. Marsden
- Molecular Cell Biology, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, U.K
| | - Daniel C. Smith
- Molecular Cell Biology, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, U.K
| | - Katherine A. H. Moore
- Molecular Cell Biology, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, U.K
| | - Jonathon P. Cook
- Molecular Cell Biology, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, U.K
| | - J. Michael Lord
- Molecular Cell Biology, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, U.K
| | - Lynne M. Roberts
- Molecular Cell Biology, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, U.K
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Citores L, Ferreras JM, Muñoz R, Benítez J, Jiménez P, Girbés T. Targeting cancer cells with transferrin conjugates containing the non-toxic type 2 ribosome-inactivating proteins nigrin b or ebulin l. Cancer Lett 2002; 184:29-35. [PMID: 12104045 DOI: 10.1016/s0304-3835(02)00169-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Nigrin b and ebulin l are type 2 ribosome-inactivating proteins (RIPs) with 10(4) times less cellular and in vivo toxicity than ricin that are currently being considered for the construction of anti-cancer conjugates. Here we provide evidence that both RIPs can be used for the construction of conjugates directed to a target such as the transferrin receptor (TfR), which is over-expressed in cancer cells. Nigrin b- and ebulin l-transferrin conjugates were constructed with no substantial reduction in the translational inhibitory molecular activity of either RIPs. Conjugation with transferrin decreased the IC(50) of the proteins from 3 x 10(-7)M (nigrin b) and 1.5 x 10(-8)M (ebulin l) to 3.5 x 10(-10)M in HeLa cells. Thus, both conjugates could be considered as useful tools for targeting TfR-over-expressing cancer cells.
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Affiliation(s)
- Lucía Citores
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Valladolid, Spain
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Nielsen K, Boston RS. RIBOSOME-INACTIVATING PROTEINS: A Plant Perspective. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 2001; 52:785-816. [PMID: 11337416 DOI: 10.1146/annurev.arplant.52.1.785] [Citation(s) in RCA: 203] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ribosome-inactivating proteins (RIPs) are toxic N-glycosidases that depurinate the universally conserved alpha-sarcin loop of large rRNAs. This depurination inactivates the ribosome, thereby blocking its further participation in protein synthesis. RIPs are widely distributed among different plant genera and within a variety of different tissues. Recent work has shown that enzymatic activity of at least some RIPs is not limited to site-specific action on the large rRNAs of ribosomes but extends to depurination and even nucleic acid scission of other targets. Characterization of the physiological effects of RIPs on mammalian cells has implicated apoptotic pathways. For plants, RIPs have been linked to defense by antiviral, antifungal, and insecticidal properties demonstrated in vitro and in transgenic plants. How these effects are brought about, however, remains unresolved. At the least, these results, together with others summarized here, point to a complex biological role. With genetic, genomic, molecular, and structural tools now available for integrating different experimental approaches, we should further our understanding of these multifunctional proteins and their physiological functions in plants.
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Affiliation(s)
- Kirsten Nielsen
- Department of Botany, North Carolina State University, Raleigh, North Carolina 27695-7612; e-mail: ;
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Pascal JM, Day PJ, Monzingo AF, Ernst SR, Robertus JD, Iglesias R, Pérez Y, Férreras JM, Citores L, Girbés T. 2.8-A crystal structure of a nontoxic type-II ribosome-inactivating protein, ebulin l. Proteins 2001; 43:319-26. [PMID: 11288182 DOI: 10.1002/prot.1043] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Ebulin l is a type-II ribosome-inactivating protein (RIP) isolated from the leaves of Sambucus ebulus L. As with other type-II RIP, ebulin is a disulfide-linked heterodimer composed of a toxic A chain and a galactoside-specific lectin B chain. A normal level of ribosome-inactivating N-glycosidase activity, characteristic of the A chain of type-II RIP, has been demonstrated for ebulin l. However, ebulin is considered a nontoxic type-II RIP due to a reduced cytotoxicity on whole cells and animals as compared with other toxic type-II RIP like ricin. The molecular cloning, amino acid sequence, and the crystal structure of ebulin l are presented and compared with ricin. Ebulin l is shown to bind an A-chain substrate analogue, pteroic acid, in the same manner as ricin. The galactoside-binding ability of ebulin l is demonstrated crystallographically with a complex of the B chain with galactose and with lactose. The negligible cytotoxicity of ebulin l is apparently due to a reduced affinity for galactosides. An altered mode of galactoside binding in the 2gamma subdomain of the lectin B chain primarily causes the reduced affinity.
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Affiliation(s)
- J M Pascal
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA
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