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Morrison G, Henry N, Kopytynski M, Chen R. A bioinspired pseudopeptide-based intracellular delivery platform enhances the cytotoxicity of a ribosome-inactivating protein through multiple death pathways. Biomater Sci 2024; 12:5010-5022. [PMID: 39177215 PMCID: PMC11342633 DOI: 10.1039/d4bm00600c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 08/09/2024] [Indexed: 08/24/2024]
Abstract
Saporin is a 28 621 Da protein and plant toxin possessing rRNA N-glycosidase activity. Due to its potent ribosome-inactivating ability, saporin is commonly studied as an anticancer agent. However, its enzymatic activity is greatly hindered by its poor plasma membrane permeability. To overcome this barrier, we used a bioinspired intracellular delivery platform based on the pH-responsive pseudopeptide, poly(L-lysine isophthalamide) grafted with L-phenylalanine at a stoichiometric molar percentage of 50% (PP50). PP50 was co-incubated with saporin (PP50/saporin) in a mildly acidic pH environment to aid intracellular delivery and increase saporin's therapeutic potential. We demonstrated that PP50 greatly enhanced the cytotoxicity of saporin in the 2D monolayer of A549 cells and 3D A549 multicellular spheroids whilst remaining non-toxic when administered alone. To elucidate the mechanism of cell death, we assessed the activation of caspases, the inhibition of protein synthesis, the onset of apoptosis and the mechanism of PP50/saporin entry. Inhibition of protein synthesis and activation of caspases 3/7, 8 and 9 were found to occur before the onset of apoptosis and cell death. PP50/saporin was also shown to rely on micropinocytosis and caveolae-mediated endocytosis for cell entry. In addition, fluorescein isothiocyanate-labelled saporin (FITC-saporin) was localized within the cytoplasm and nuclei when delivered with Cyanine5-labelled PP50 (Cy5-PP50). Taken together, this suggests that multiple pathways are triggered to initiate apoptosis and cell death in cells treated with PP50/saporin. Therefore, these results make PP50 a potential intracellular delivery platform for the internalization of protein therapeutics.
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Affiliation(s)
- Gabriella Morrison
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
| | - Nicole Henry
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
| | - Michal Kopytynski
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
| | - Rongjun Chen
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
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Choudhary N, Lodha ML, Baranwal VK. The role of enzymatic activities of antiviral proteins from plants for action against plant pathogens. 3 Biotech 2020; 10:505. [PMID: 33184592 PMCID: PMC7642053 DOI: 10.1007/s13205-020-02495-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/19/2020] [Indexed: 11/25/2022] Open
Abstract
Antiviral proteins (AVPs) from plants possess multiple activities, such as N-glycosidase, RNase, DNase enzymatic activity, and induce pathogenesis-related proteins, salicylic acid, superoxide dismutase, peroxidase, and catalase. The N-glycosidase activity releases the adenine residues from sarcin/ricin (S/R) loop of large subunit of ribosomes and interfere the host protein synthesis process and this activity has been attributed for antiviral activity in plant. It has been shown that AVP binds directly to viral genome-linked protein of plant viruses and interfere with protein synthesis of virus. AVPs also possess the RNase and DNase like activity and may be targeting nucleic acid of viruses directly. Recently, the antifungal, antibacterial, and antiinsect properties of AVPs have also been demonstrated. Gene encoding for AVPs has been used for the development of transgenic resistant crops to a broad range of plant pathogens and insect pests. However, the cytotoxicity has been observed in transgenic crops using AVP gene in some cases which can be a limiting factor for its application in agriculture. In this review, we have reviewed various aspects of AVPs particularly their characteristics, possible mode of action and application.
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Affiliation(s)
- Nandlal Choudhary
- Amity Institute of Virology & Immunology, Amity University Uttar Pradesh, Noida, 201313 India
| | - M. L. Lodha
- Division of Biochemistry, Indian Agricultural Research Institute, Pusa, New Delhi, 110012 India
| | - V. K. Baranwal
- Division of Plant Pathology, Indian Agricultural Research Institute, Pusa, New Delhi, 110012 India
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Chen YJ, Zhu JQ, Fu XQ, Su T, Li T, Guo H, Zhu PL, Lee SKW, Yu H, Tse AKW, Yu ZL. Ribosome-Inactivating Protein α-Momorcharin Derived from Edible Plant Momordica charantia Induces Inflammatory Responses by Activating the NF-kappaB and JNK Pathways. Toxins (Basel) 2019; 11:toxins11120694. [PMID: 31779275 PMCID: PMC6949964 DOI: 10.3390/toxins11120694] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 11/17/2019] [Accepted: 11/25/2019] [Indexed: 01/25/2023] Open
Abstract
Alpha-momorcharin (α-MMC), a member of the ribosome-inactivating protein (RIP) family, has been found in the seeds of Momordica charantia (bitter melon). α-MMC contributes a number of pharmacological activities; however, its inflammatory properties have not been well studied. Here, we aim to determine the inflammatory responses induced by recombinant α-MMC and identify the underlying mechanisms using cell culture and animal models. Recombinant α-MMC was generated in Rosetta™(DE3)pLysS and purified by the way of nitrilotriacetic acid (NTA) chromatography. Treatment of recombinant α-MMC at 40 μg/mL exerted sub-lethal cytotoxic effect on THP-1 monocytic cells. Transcriptional profiling revealed that various genes coding for cytokines and other proinflammatory proteins were upregulated upon recombinant α-MMC treatment in THP-1 cells, including MCP-1, IL-8, IL-1β, and TNF-α. Recombinant α-MMC was shown to activate IKK/NF-κB and JNK pathways and the α-MMC-induced inflammatory gene expression could be blocked by IKKβ and JNK inhibitors. Furthermore, murine inflammatory models further demonstrated that α-MMC induced inflammatory responses in vivo. We conclude that α-MMC stimulates inflammatory responses in human monocytes by activating of IKK/NF-κB and JNK pathways, raising the possibility that consumption of α-MMC-containing food may lead to inflammatory-related diseases.
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Affiliation(s)
- Ying-Jie Chen
- Center for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Jia-Qian Zhu
- Center for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Xiu-Qiong Fu
- Center for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Tao Su
- Center for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Ting Li
- Center for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Hui Guo
- Center for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Pei-Li Zhu
- Center for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Sally Kin-Wah Lee
- Center for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Hua Yu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Anfernee Kai-Wing Tse
- Food Science and Technology Program, Beijing Normal University-Hong Kong Baptist University United International College, Zhuhai 519087, China
- Correspondence: (A.K.-W.T.); (Z.-L.Y.); Tel.: +86-0756-3620147 (A.K.-W.T.); +852-3411-2465 (Z.-L.Y.)
| | - Zhi-Ling Yu
- Center for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
- Correspondence: (A.K.-W.T.); (Z.-L.Y.); Tel.: +86-0756-3620147 (A.K.-W.T.); +852-3411-2465 (Z.-L.Y.)
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Structure and Activity of a Cytosolic Ribosome-Inactivating Protein from Rice. Toxins (Basel) 2019; 11:toxins11060325. [PMID: 31174339 PMCID: PMC6628440 DOI: 10.3390/toxins11060325] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 05/30/2019] [Accepted: 06/04/2019] [Indexed: 02/07/2023] Open
Abstract
Ribosome-inactivating proteins (RIPs) are cytotoxic enzymes that inhibit protein translation by depurinating ribosomal RNA. Although most plant RIPs are synthesized with leader sequences that sequester them away from the host ribosomes, several RIPs from cereals lack these signal peptides and therefore probably reside in the cytosol near the plant ribosomes. More than 30 RIP genes have been identified in the rice (Oryza sativa spp. japonica) genome, many of them lacking a signal peptide. This paper focuses on a presumed cytosolic type-1 RIP from rice, referred to as OsRIP1. Using 3D modeling it is shown that OsRIP1 structurally resembles other cereal RIPs and has an active site that meets the requirements for activity. Furthermore, localization studies indicate that OsRIP1-eGFP fusion proteins reside in the nucleocytoplasmic space when expressed in epidermal cells of Nicotiana benthamiana or Arabidopsis thaliana suspension cells. Finally, OsRIP1 was recombinantly produced in Escherichia coli and was demonstrated to possess catalytic activity. Interestingly, this recombinant RIP inactivates wheat ribosomes far less efficiently than rabbit ribosomes in an in vitro system. These findings raise some interesting questions concerning the mode of action and physiological role of OsRIP1. This is the first time a RIP from rice is investigated at protein level and is shown to possess biological activity.
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Plant Ribosome-Inactivating Proteins: Progesses, Challenges and Biotechnological Applications (and a Few Digressions). Toxins (Basel) 2017; 9:toxins9100314. [PMID: 29023422 PMCID: PMC5666361 DOI: 10.3390/toxins9100314] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 09/29/2017] [Accepted: 10/03/2017] [Indexed: 12/11/2022] Open
Abstract
Plant ribosome-inactivating protein (RIP) toxins are EC3.2.2.22 N-glycosidases, found among most plant species encoded as small gene families, distributed in several tissues being endowed with defensive functions against fungal or viral infections. The two main plant RIP classes include type I (monomeric) and type II (dimeric) as the prototype ricin holotoxin from Ricinus communis that is composed of a catalytic active A chain linked via a disulphide bridge to a B-lectin domain that mediates efficient endocytosis in eukaryotic cells. Plant RIPs can recognize a universally conserved stem-loop, known as the α-sarcin/ ricin loop or SRL structure in 23S/25S/28S rRNA. By depurinating a single adenine (A4324 in 28S rat rRNA), they can irreversibly arrest protein translation and trigger cell death in the intoxicated mammalian cell. Besides their useful application as potential weapons against infected/tumor cells, ricin was also used in bio-terroristic attacks and, as such, constitutes a major concern. In this review, we aim to summarize past studies and more recent progresses made studying plant RIPs and discuss successful approaches that might help overcoming some of the bottlenecks encountered during the development of their biomedical applications.
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De Zaeytijd J, Van Damme EJM. Extensive Evolution of Cereal Ribosome-Inactivating Proteins Translates into Unique Structural Features, Activation Mechanisms, and Physiological Roles. Toxins (Basel) 2017; 9:E123. [PMID: 28353660 PMCID: PMC5408197 DOI: 10.3390/toxins9040123] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 03/21/2017] [Accepted: 03/25/2017] [Indexed: 11/16/2022] Open
Abstract
Ribosome-inactivating proteins (RIPs) are a class of cytotoxic enzymes that can depurinate rRNAs thereby inhibiting protein translation. Although these proteins have also been detected in bacteria, fungi, and even some insects, they are especially prevalent in the plant kingdom. This review focuses on the RIPs from cereals. Studies on the taxonomical distribution and evolution of plant RIPs suggest that cereal RIPs have evolved at an enhanced rate giving rise to a large and heterogeneous RIP gene family. Furthermore, several cereal RIP genes are characterized by a unique domain architecture and the lack of a signal peptide. This advanced evolution of cereal RIPs translates into distinct structures, activation mechanisms, and physiological roles. Several cereal RIPs are characterized by activation mechanisms that include the proteolytic removal of internal peptides from the N-glycosidase domain, a feature not documented for non-cereal RIPs. Besides their role in defense against pathogenic fungi or herbivorous insects, cereal RIPs are also involved in endogenous functions such as adaptation to abiotic stress, storage, induction of senescence, and reprogramming of the translational machinery. The unique properties of cereal RIPs are discussed in this review paper.
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Affiliation(s)
- Jeroen De Zaeytijd
- Lab Biochemistry and Glycobiology, Department of Molecular Biotechnology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium.
| | - Els J M Van Damme
- Lab Biochemistry and Glycobiology, Department of Molecular Biotechnology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium.
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Biological and antipathogenic activities of ribosome-inactivating proteins from Phytolacca dioica L. Biochim Biophys Acta Gen Subj 2016; 1860:1256-64. [DOI: 10.1016/j.bbagen.2016.03.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 02/16/2016] [Accepted: 03/07/2016] [Indexed: 12/30/2022]
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Citores L, Iglesias R, Gay C, Ferreras JM. Antifungal activity of the ribosome-inactivating protein BE27 from sugar beet (Beta vulgaris L.) against the green mould Penicillium digitatum. MOLECULAR PLANT PATHOLOGY 2016; 17:261-271. [PMID: 25976013 PMCID: PMC6638414 DOI: 10.1111/mpp.12278] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The ribosome-inactivating protein BE27 from sugar beet (Beta vulgaris L.) leaves is an apoplastic protein induced by signalling compounds, such as hydrogen peroxide and salicylic acid, which has been reported to be involved in defence against viruses. Here, we report that, at a concentration much lower than that present in the apoplast, BE27 displays antifungal activity against the green mould Penicillium digitatum, a necrotrophic fungus that colonizes wounds and grows in the inter- and intracellular spaces of the tissues of several edible plants. BE27 is able to enter into the cytosol and kill fungal cells, thus arresting the growth of the fungus. The mechanism of action seems to involve ribosomal RNA (rRNA) N-glycosylase activity on the sarcin-ricin loop of the major rRNA which inactivates irreversibly the fungal ribosomes, thus inhibiting protein synthesis. We compared the C-terminus of the BE27 structure with antifungal plant defensins and hypothesize that a structural motif composed of an α-helix and a β-hairpin, similar to the γ-core motif of defensins, might contribute to the specific interaction with the fungal plasma membranes, allowing the protein to enter into the cell.
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Affiliation(s)
- Lucía Citores
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Sciences, University of Valladolid, 47011, Valladolid, Spain
| | - Rosario Iglesias
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Sciences, University of Valladolid, 47011, Valladolid, Spain
| | - Carolina Gay
- Laboratory of Research on Proteins, Faculty of Exact and Natural Sciences and Surveying, National University of the Northeast (UNNE), 3400, Corrientes, Argentina
| | - José Miguel Ferreras
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Sciences, University of Valladolid, 47011, Valladolid, Spain
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Schrot J, Weng A, Melzig MF. Ribosome-inactivating and related proteins. Toxins (Basel) 2015; 7:1556-615. [PMID: 26008228 PMCID: PMC4448163 DOI: 10.3390/toxins7051556] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 04/23/2015] [Accepted: 04/28/2015] [Indexed: 01/15/2023] Open
Abstract
Ribosome-inactivating proteins (RIPs) are toxins that act as N-glycosidases (EC 3.2.2.22). They are mainly produced by plants and classified as type 1 RIPs and type 2 RIPs. There are also RIPs and RIP related proteins that cannot be grouped into the classical type 1 and type 2 RIPs because of their different sizes, structures or functions. In addition, there is still not a uniform nomenclature or classification existing for RIPs. In this review, we give the current status of all known plant RIPs and we make a suggestion about how to unify those RIPs and RIP related proteins that cannot be classified as type 1 or type 2 RIPs.
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Affiliation(s)
- Joachim Schrot
- Institute of Pharmacy, Freie Universitaet Berlin, Koenigin-Luise-Str. 2 + 4, 14195 Berlin, Germany.
| | - Alexander Weng
- Institute of Pharmacy, Freie Universitaet Berlin, Koenigin-Luise-Str. 2 + 4, 14195 Berlin, Germany.
| | - Matthias F Melzig
- Institute of Pharmacy, Freie Universitaet Berlin, Koenigin-Luise-Str. 2 + 4, 14195 Berlin, Germany.
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Iglesias R, Citores L, Di Maro A, Ferreras JM. Biological activities of the antiviral protein BE27 from sugar beet (Beta vulgaris L.). PLANTA 2015; 241:421-433. [PMID: 25326773 DOI: 10.1007/s00425-014-2191-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 10/12/2014] [Indexed: 06/04/2023]
Abstract
The ribosome inactivating protein BE27 displays several biological activities in vitro that could result in a broad action against several types of pathogens. Beetin 27 (BE27), a ribosome-inactivating protein (RIP) from sugar beet (Beta vulgaris L.) leaves, is an antiviral protein induced by virus and signaling compounds such as hydrogen peroxide and salicylic acid. Its role as a defense protein has been attributed to its RNA polynucleotide:adenosine glycosidase activity. Here we tested other putative activities of BE27 that could have a defensive role against pathogens finding that BE27 displays rRNA N-glycosidase activity against yeast and Agrobacterium tumefaciens ribosomes, DNA polynucleotide:adenosine glycosidase activity against herring sperm DNA, and magnesium-dependent endonuclease activity against the supercoiled plasmid PUC19 (nicking activity). The nicking activity could be a consequence of an unusual conformation of the BE27 active site, similar to that of PD-L1, a RIP from Phytolacca dioica L. leaves. Additionally, BE27 possesses superoxide dismutase activity, thus being able to produce the signal compound hydrogen peroxide. BE27 is also toxic to COLO 320 cells, inducing apoptosis in these cells by either activating the caspase pathways and/or inhibiting protein synthesis. The combined effect of these biological activities could result in a broad action against several types of pathogens such as virus, bacteria, fungi or insects.
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Affiliation(s)
- Rosario Iglesias
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Sciences, University of Valladolid, 47011, Valladolid, Spain
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Hartmann M, Howes CG, Veldre V, Schneider S, Vaishampayan PA, Yannarell AC, Quince C, Johansson P, Björkroth KJ, Abarenkov K, Hallam SJ, Mohn WW, Nilsson RH. V-REVCOMP: automated high-throughput detection of reverse complementary 16S rRNA gene sequences in large environmental and taxonomic datasets. FEMS Microbiol Lett 2011; 319:140-5. [DOI: 10.1111/j.1574-6968.2011.02274.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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de Virgilio M, Lombardi A, Caliandro R, Fabbrini MS. Ribosome-inactivating proteins: from plant defense to tumor attack. Toxins (Basel) 2010; 2:2699-737. [PMID: 22069572 PMCID: PMC3153179 DOI: 10.3390/toxins2112699] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 10/29/2010] [Accepted: 11/04/2010] [Indexed: 12/02/2022] Open
Abstract
Ribosome-inactivating proteins (RIPs) are EC3.2.32.22 N-glycosidases that recognize a universally conserved stem-loop structure in 23S/25S/28S rRNA, depurinating a single adenine (A4324 in rat) and irreversibly blocking protein translation, leading finally to cell death of intoxicated mammalian cells. Ricin, the plant RIP prototype that comprises a catalytic A subunit linked to a galactose-binding lectin B subunit to allow cell surface binding and toxin entry in most mammalian cells, shows a potency in the picomolar range. The most promising way to exploit plant RIPs as weapons against cancer cells is either by designing molecules in which the toxic domains are linked to selective tumor targeting domains or directly delivered as suicide genes for cancer gene therapy. Here, we will provide a comprehensive picture of plant RIPs and discuss successful designs and features of chimeric molecules having therapeutic potential.
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Affiliation(s)
| | - Alessio Lombardi
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Milan, Italy;
| | - Rocco Caliandro
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Bari, Italy;
| | - Maria Serena Fabbrini
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Milan, Italy;
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Tourlakis ME, Karran RA, Desouza L, Siu KWM, Hudak KA. Homodimerization of pokeweed antiviral protein as a mechanism to limit depurination of pokeweed ribosomes. MOLECULAR PLANT PATHOLOGY 2010; 11:757-767. [PMID: 21029321 PMCID: PMC6640456 DOI: 10.1111/j.1364-3703.2010.00640.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Ribosome inactivating proteins are glycosidases synthesized by many plants and have been hypothesized to serve in defence against pathogens. These enzymes catalytically remove a conserved purine from the sarcin/ricin loop of the large ribosomal RNA, which has been shown in vitro to limit protein synthesis. The resulting toxicity suggests that plants may possess a mechanism to protect their ribosomes from depurination during the synthesis of these enzymes. For example, pokeweed antiviral protein (PAP) is cotranslationally inserted into the lumen of the endoplasmic reticulum and travels via the endomembrane system to be stored in the cell wall. However, some PAP may retrotranslocate across the endoplasmic reticulum membrane to be released back into the cytosol, thereby exposing ribosomes to depurination. In this work, we isolated and characterized a complexed form of the enzyme that exhibits substantially reduced activity. We showed that this complex is a homodimer of PAP and that dimerization involves a peptide that contains a conserved aromatic amino acid, tyrosine 123, located in the active site of the enzyme. Bimolecular fluorescence complementation demonstrated that the homodimer may form in vivo and that dimerization is prevented by the substitution of tyrosine 123 for alanine. The homodimer is a minor form of PAP, observed only in the cytosol of cells and not in the apoplast. Taken together, these data support a novel mechanism for the limitation of depurination of autologous ribosomes by molecules of the protein that escape transport to the cell wall by the endomembrane system.
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15
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Qin X, Zheng X, Shao C, Gao J, Jiang L, Zhu X, Yan F, Tang L, Xu Y, Chen F. Stress-induced curcin-L promoter in leaves of Jatropha curcas L. and characterization in transgenic tobacco. PLANTA 2009; 230:387-95. [PMID: 19475419 DOI: 10.1007/s00425-009-0956-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2009] [Accepted: 05/12/2009] [Indexed: 05/16/2023]
Abstract
Ribosome-inactivating proteins (RIPs) represent a type of protein that universally inactivates the ribosome thus inhibiting protein biosynthesis. Curcin-L was a type I RIP found in Jatropha curcas L.. Its expression could be activated in leaves by treatments with abscisic acid, salicylic acid, polyethylene glycol, temperature 4, 45 degrees C and ultraviolet light. A 654 bp fragment of a 5' flanking region preceding the curcin-L gene, designated CP2, was cloned from the J. curcas genome and its expression pattern was studied via the expression of the beta-glucuronidase (GUS) gene in transgenic tobacco. Analysis of GUS activities showed that the CP2 was leaf specific, and was able to drive the expression of the reporter gene under stress-induction conditions. Analysis of a series of 5'-deletions of the CP2 suggested that several promoter motifs were necessary to respond to environmental stresses.
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Affiliation(s)
- Xiaobo Qin
- College of Life Sciences, Sichuan University, 610064, Chengdu, People's Republic of China.
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16
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Kawade K, Ishizaki T, Masuda K. Differential expression of ribosome-inactivating protein genes during somatic embryogenesis in spinach (Spinacia oleracea). PHYSIOLOGIA PLANTARUM 2008; 134:270-281. [PMID: 18494862 DOI: 10.1111/j.1399-3054.2008.01129.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Root segments from spinach (Spinacia oleracea L. cv. Jiromaru) seedlings form embryogenic callus (EC) that responded to exogenous GA(3) by accumulating a 31-kDa glycoprotein [BP31 or S. oleracea ribosome-inactivating protein (EC 3.2.2.22) (SoRIP1)] in association with the expression of embryogenic potential. Microsequencing of this protein revealed significant similarity with type 1 RIPs. We identified cDNAs for SoRIP1 and S. oleracea RIP2 (SoRIP2), a novel RIP having a consensus shiga/ricin toxic domain and performed a comparative analysis of the expression of SoRIPs during somatic embryogenesis. Western blotting and quantitative polymerase chain reaction analyses revealed that the expression of SoRIP1 in calli increased remarkably in association with the acquisition of embryogenic potential, although the expression in somatic embryos decreased moderately with their development. However, the expression of SoRIP2 in calli remained low and constant but increased markedly with the development of somatic embryos. Treatment of callus with GA(3) and/or ABA for 24 h, or with ABA for a longer period, failed to stimulate the expression of either gene. Immunohistochemistry showed that SoRIP1 preferentially accumulated in the proembryos and peripheral meristem of somatic embryos early in development. Appreciable expression of SoRIP2 was not detected in the callus, but intense expression was found in the epidermis of somatic embryos. These results suggest that the expression of spinach RIP genes is differentially regulated in a development-dependent fashion during somatic embryogenesis in spinach.
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Affiliation(s)
- Kensuke Kawade
- Laboratory of Plant Functional Biology, Department of Agrobiology, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
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Iglesias R, Pérez Y, Citores L, Ferreras JM, Méndez E, Girbés T. Elicitor-dependent expression of the ribosome-inactivating protein beetin is developmentally regulated. JOURNAL OF EXPERIMENTAL BOTANY 2008; 59:1215-1223. [PMID: 18343888 DOI: 10.1093/jxb/ern030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
BE27 and BE29 are two forms of beetin, a virus-inducible type 1 ribosome-inactivating protein isolated from leaves of Beta vulgaris L. Western blot analysis revealed the presence of beetin forms in adult plants but not in germ or young plants, indicating that the expression of these proteins is developmentally regulated. While beetins are expressed only in adult plants, their transcripts are present through all stages of development. In addition, the treatment of B. vulgaris leaves with mediators of plant-acquired resistance such as salicylic acid and hydrogen peroxide promoted the expression of beetin by induction of its transcript, but only in adult plants. The plant expresses three mRNAs which differ only in their 3' untranslated region. All these observations suggest a dual regulation of beetin expression, i.e. at the post-transcriptional and transcriptional levels. Additionally, total RNA isolated from leaves treated with hydrogen peroxide, which express high levels of active beetin, is not de-adenylated by endogenous beetin, nor in vitro by the addition of BE27, thus suggesting that sugar beet ribosomes are resistant to beetin.
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Affiliation(s)
- Rosario Iglesias
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Valladolid, E-47005 Valladolid, Spain
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18
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Hao Q, Peumans WJ, Van Damme EJ. Type-1 ribosome-inactivating protein from iris (Iris hollandica var. Professor Blaauw) binds specific genomic DNA fragments. Biochem J 2001; 357:875-80. [PMID: 11463360 PMCID: PMC1222019 DOI: 10.1042/0264-6021:3570875] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The capacity of IRIP, a type-1 ribosome-inactivating protein (RIP) isolated from the bulbs of Iris hollandica, to bind specific DNA sequences from a mixture of approx. 200 bp (average length) fragments of total genomic DNA from Iris genome was studied. Fragments that were preferentially bound by IRIP were enriched by several cycles of affinity binding and PCR, and were cloned and sequenced. The selected DNA fragments do not share conserved sequences, indicating that IRIP does not bind DNA fragments in a strictly sequence-specific manner. According to sequence analysis, most IRIP-bound fragments contain one or more possible free energy-stable hairpin structure(s) in their secondary structure, which may be the basis for recognition between IRIP and these DNA fragments. Some, but not all, DNA fragments moderately lower the RNA N-glycosidase activity of IRIP towards rabbit reticulocyte lysate ribosomes. IRIP does not remove adenines from the binding fragments, which implies that it does not act as a polynucleotide:adenosine glycosidase towards these DNA fragments. The selective binding of IRIP to conspecific DNA fragments is also discussed in view of the novel concept that RIPs may act as DNA-binding proteins with a regulatory activity on gene expression.
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Affiliation(s)
- Q Hao
- Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium
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19
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Peumans WJ, Hao Q, Van Damme EJ. Ribosome-inactivating proteins from plants: more than RNA N-glycosidases? FASEB J 2001; 15:1493-506. [PMID: 11427481 DOI: 10.1096/fj.00-0751rev] [Citation(s) in RCA: 210] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Many plants contain proteins that are capable of inactivating ribosomes and accordingly are called ribosome-inactivating proteins or RIPs. These typical plant proteins receive a lot of attention in biological and biomedical research because of their unique biological activities toward animal and human cells. In addition, evidence is accumulating that some RIPs play a role in plant defense and hence can be exploited in plant protection. To understand the mode of action of RIPs and to optimize their medical and therapeutical applications and their use as antiviral compounds in plant protection, intensive efforts have been made to unravel the enzymatic activities of RIPs and provide a structural basis for these activities. Though marked progress has been made during the last decade, the enzymatic activity of RIPs has become a controversial issue because of the concept that RIPs possess, in addition to their classical RNA N-glycosidase and polynucleotide:adenosine glycosidase activity, other unrelated enzymatic activities. Moreover, the presumed novel enzymatic activities, especially those related to diverse nuclease activities, are believed to play an important role in various biological activities of RIPs. However, both the novel enzymatic activities and their presumed involvement in the biological activities of RIPs have been questioned because there is evidence that the activities observed are due to contaminating enzymes. We offer a critical review of the pros and cons of the putative novel enzymatic activities of RIPs. Based on the available data, it is suggested that there is little conclusive evidence in support of the presumed activities and that in the past too little attention has been given to the purity of the RIP preparation. The antiviral activity and mode of action of RIPs in plants are discussed in view of their classical and presumed novel enzymatic activities.
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Affiliation(s)
- W J Peumans
- Laboratory of Phytopathology and Plant Protection, Katholieke Universiteit Leuven, 3001 Leuven, Belgium
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20
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Affiliation(s)
- P Wang
- Biotechnology Center for Agriculture and the Environment, Rutgers University, New Brunswick, New Jersey 08901, USA
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21
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Song SK, Choi Y, Moon YH, Kim SG, Choi YD, Lee JS. Systemic induction of a Phytolacca insularis antiviral protein gene by mechanical wounding, jasmonic acid, and abscisic acid. PLANT MOLECULAR BIOLOGY 2000; 43:439-50. [PMID: 11052196 DOI: 10.1023/a:1006444322626] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We have isolated a gene encoding a ribosome-inactivating protein (RIP) from Phytolacca insularis, designated as P. insularis antiviral protein 2 (PIP2). The PIP2 gene contained an open reading frame encoding a polypeptide of 315 amino acids. The deduced amino acid sequence of PIP2 was similar to those of other RIPs from Phytolacca plants. Recombinant PIP2 was expressed in Escherichia coli and was used to investigate its biological activities. Recombinant PIP2 inhibited protein synthesis in rabbit reticulocyte lysate by inactivating ribosomes through N-glycosidase activity. It also exhibited antiviral activity against tobacco mosaic virus (TMV). Expression of the PIP2 gene was developmentally regulated in leaves and roots of P. insularis. Furthermore, expression of the PIP2 gene was induced in leaves by mechanical wounding. The wound induction of the PIP2 gene was systemic. Expression of the PIP2 gene also increased in leaves in a systemic manner after treatment with jasmonic acid (JA) and abscisic acid (ABA), but not with salicylic acid (SA). These results imply that plants have employed the systemic synthesis of the defensive proteins to protect themselves more efficiently from infecting viruses.
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MESH Headings
- Abscisic Acid/pharmacology
- Amino Acid Sequence
- Blotting, Southern
- Cyclopentanes/pharmacology
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- DNA, Plant/genetics
- DNA, Recombinant/genetics
- DNA, Recombinant/metabolism
- Gene Expression Regulation, Developmental/drug effects
- Gene Expression Regulation, Plant/drug effects
- Molecular Sequence Data
- N-Glycosyl Hydrolases
- Oxylipins
- Plant Growth Regulators/pharmacology
- Plant Leaves/genetics
- Plant Leaves/growth & development
- Plant Proteins/genetics
- Plant Roots/genetics
- Plant Roots/growth & development
- Plants, Toxic
- Protein Biosynthesis
- RNA, Plant/drug effects
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Ribosome Inactivating Proteins, Type 1
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Stress, Mechanical
- Nicotiana/genetics
- Nicotiana/virology
- Tobacco Mosaic Virus/growth & development
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Affiliation(s)
- S K Song
- Department of Molecular Biology and Research Center for Cell Differentiation, Seoul National University, Korea
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22
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Hudak KA, Wang P, Tumer NE. A novel mechanism for inhibition of translation by pokeweed antiviral protein: depurination of the capped RNA template. RNA (NEW YORK, N.Y.) 2000; 6:369-80. [PMID: 10744021 PMCID: PMC1369919 DOI: 10.1017/s1355838200991337] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Pokeweed antiviral protein (PAP) is known to inactivate ribosomes by removal of a specific adenine from the sarcin/ricin (S/R) loop of the large rRNA, thereby inhibiting translation. We demonstrate here that in addition to the previously identified adenine (A4324), PAP removes another adenine (A4321) and a guanine (G4323) from the eukaryotic large rRNA. Recent results indicate that the antiviral activity of PAP may not be due to depurination of host ribosomes. Using PAP mutants that do not depurinate either tobacco or reticulocyte lysate rRNA, we show that PAP inhibits translation of brome mosaic virus (BMV) and potato virus X (PVX) RNAs without depurinating ribosomes. Furthermore, translation of only capped, but not uncapped, luciferase transcripts is inhibited by PAP, providing evidence that PAP and PAP mutants are able to distinguish between capped and uncapped transcripts. Translation inhibition of BMV RNAs is overcome by treatment with PAP in the presence of increasing concentrations of the cap analog m7GpppG, but not GpppG or GTP, indicating that PAP recognizes the cap structure. Incubation of BMV RNAs or the capped luciferase transcripts with PAP results in depurination of either RNA. In contrast, uncapped luciferase transcripts are not depurinated after incubation with identical concentrations of PAP. These results demonstrate for the first time that PAP can inhibit translation by a mechanism other than ribosome depurination, by recognizing the cap structure and specifically depurinating the capped RNAs.
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Affiliation(s)
- K A Hudak
- Biotechnology Center for Agriculture and the Environment, and the Department of Plant Pathology, Cook College, Rutgers University, New Brunswick, New Jersey 08903, USA
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23
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Tumer NE, Hwang DJ, Bonness M. C-terminal deletion mutant of pokeweed antiviral protein inhibits viral infection but does not depurinate host ribosomes. Proc Natl Acad Sci U S A 1997; 94:3866-71. [PMID: 9108070 PMCID: PMC20533 DOI: 10.1073/pnas.94.8.3866] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Pokeweed antiviral protein (PAP), a 29-kDa protein isolated from Phytolacca americana, inhibits translation by catalytically removing a specific adenine residue from the large rRNA of the 60S subunit of eukaryotic ribosomes. In addition to its ribosome-inactivating ability, PAP has potent antiviral activity against many plant and animal viruses, including HIV. We recently described the isolation and characterization of nontoxic PAP mutants, NT123-2, which has a point mutation (E176V) in the active site that abolishes enzymatic activity, and NT124-3, which has a nonsense mutation that results in deletion of the C-terminal 25 aa (W237Stop). In vitro translation of rabbit reticulocyte lysate ribosomes was inhibited by the C-terminal deletion mutant, but not by the active site mutant. We expressed both mutants in transgenic tobacco and showed that, unlike PAP or variant PAP, neither mutant is toxic to transgenic plants. In vivo depurination of rRNA was detected in transgenic tobacco expressing variant PAP, but not in transgenic plants expressing either the active site mutant or the C-terminal deletion mutant PAP. When extracts from transgenic plants containing the mutant PAPs were exogenously applied to tobacco leaves in the presence of potato virus X (PVX), the C-terminal deletion mutant had antiviral activity, while the active site mutant had no antiviral activity. Furthermore, transgenic plants expressing low levels of the C-terminal deletion mutant showed resistance to PVX infection, while transgenic plants expressing very high levels of the active site mutant PAP were not resistant to PVX. Our results demonstrate that an intact active site of PAP is necessary for antiviral activity, toxicity, and in vivo depurination of tobacco ribosomes. However, an intact active site is not sufficient for all these activities. An intact C terminus is also required for toxicity and depurination of tobacco ribosomes in vivo, but not for antiviral activity, suggesting that antiviral activity of PAP can be dissociated from its toxicity.
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Affiliation(s)
- N E Tumer
- Agricultural Biotechnology Center and Department of Plant Pathology, Rutgers University, Cook College, New Brunswick, NJ 08903-0231, USA.
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24
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Fabbrini MS, Rappocciolo E, Carpani D, Solinas M, Valsasina B, Breme U, Cavallaro U, Nykjaer A, Rovida E, Legname G, Soria MR. Characterization of a saporin isoform with lower ribosome-inhibiting activity. Biochem J 1997; 322 ( Pt 3):719-27. [PMID: 9148741 PMCID: PMC1218247 DOI: 10.1042/bj3220719] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have expressed in Escherichia coli five isoforms of saporin, a single-chain ribosome-inactivating protein (RIP). Translation inhibition activities of the purified recombinant polypeptides in vitro were compared with those of recombinant dianthin 30, a less potent and closely related RIP, and of ricin A chain. Dianthin 30, and a saporin isoform encoded by a cDNA from leaf tissue (SAP-C), both had about one order of magnitude lower activity in translation inhibition assays than all other isoforms of saporin tested. We recently demonstrated that saporin extracted from seeds of Saponaria officinalis binds to alpha2-macroglobulin receptor (alpha2MR; also termed low density lipoprotein-receptor-related-protein), indicating a general mechanism of interaction of plant RIPs with the alpha2MR system [Cavallaro, Nykjaer, Nielsen and Soria (1995) Eur. J. Biochem. 232, 165-171]. Here we report that SAP-C bound to alpha2MR equally well as native saporin. However, the same isoform had about ten times lower cytotoxicity than the other saporin isoforms towards different cell lines. This indicates that the lower cell-killing ability of the SAP-C isoform is presumably due to its altered interaction with the protein synthesis machinery of target cells. Since saporin binding to the alpha2MR is competed by heparin, we also tested in cell-killing experiments Chinese hamster ovary cell lines defective for expression of either heparan sulphates or proteoglycans. No differences were observed in cytotoxicity using native saporin or the recombinant isoforms. Therefore saporin binding to the cell surface should not be mediated by interaction with proteoglycans, as is the case for other alpha2MR ligands.
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Affiliation(s)
- M S Fabbrini
- Department of Biological and Technological Research-Dibit, San Raffaele Scientific Institute, via Olgettina 58, 20132 Milano
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25
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Hornung E, Wajant H, Jeske H, Mundry KW. Cloning of a cDNA encoding a new ribosome-inactivating protein from Beta vulgaris vulgaris (mangold). Gene 1996; 170:233-6. [PMID: 8666251 DOI: 10.1016/0378-1119(95)00802-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
By means of a lambda ZAP II cDNA library constructed from seedings of Beta vulgaris vulgaris and immunoscreening, a cDNA clone containing a partial sequence of a new ribosome-inactivating protein (RIP) was obtained. As confirmed by Western blot analysis, this clone produced a RIP upon induction with IPTG. We called it betavulgin (Bvg). The recombinant protein (re-Bvg) was somewhat smaller than plant-derived RIP (28 versus 30 and 32 kDa), but showed the specific N-glycosidase activity on tobacco ribosomes, confirming its RIP character. The cDNA was sequenced and the missing 5'-end was established by RACE using bvg-specific primers. The entire cDNA was 1080 nucleotides in length and encoded a protein of 272 amino acids with a sequence identity of 26-40% with other RIP.
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Affiliation(s)
- E Hornung
- Biological Institute, Department of Molecular Biology and Plant Virology, Stuttgart, Germany
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26
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Chaddock JA, Monzingo AF, Robertus JD, Lord JM, Roberts LM. Major structural differences between pokeweed antiviral protein and ricin A-chain do not account for their differing ribosome specificity. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 235:159-66. [PMID: 8631323 DOI: 10.1111/j.1432-1033.1996.00159.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Pokeweed antiviral protein (PAP) and the A-chain of ricin (RTA) are two members of a family of ribosome-inactivating proteins (RIPS) that are characterised by their ability to catalytically depurinate eukaryotic ribosomes, a modification that makes the ribosomes incapable of protein synthesis. In contrast to RTA, PAP can also inactivate prokaryotic ribosomes. In order to investigate the reason for this differing ribosome specificity, a series of PAP/RTA hybrid proteins was prepared to test for their ability to depurinate prokaryotic and eukaryotic ribosomes. Information from the X-ray structures of RTA and PAP was used to design gross polypeptide switches and specific peptide insertions. Initial gross polypeptide swaps created hybrids that had altered ribosome inactivation properties. Preliminary results suggest that the carboxy-terminus of the RIPs (PAP 219-262) does not contribute to ribosome recognition, whereas polypeptide swaps in the amino-terminal half of the proteins did affect ribosome inactivation. Structural examination identified three loop regions that were different in both structure and composition within the amino-terminal region. Directed substitution of RTA sequences into PAP at these sites, however, had little effect on the ribosome inactivation characteristics of the mutant PAPs, suggesting that the loops were not crucial for prokaryotic ribosome recognition. On the basis of these results we have identified regions of RIP primary sequence that may be important in ribosome recognition. The implications of this work are discussed.
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Affiliation(s)
- J A Chaddock
- Department of Biological Sciences, University of Warwick, Coventry, UK
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27
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Brigotti M, Carnicelli D, Alvergna P, Pallanca A, Sperti S, Montanaro L. Differential up-regulation by tRNAs of ribosome-inactivating proteins. FEBS Lett 1995; 373:115-8. [PMID: 7589447 DOI: 10.1016/0014-5793(95)01023-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Some plant ribosome-inactivating proteins (RIPs) with RNA-N-glycosidase activity on 28S RNA require, for the inactivation of ribosomes, the presence of macromolecular cofactors present in post-ribosomal supernatants. In the case of gelonin one of the cofactors is tRNATrp lacking one or two nucleotides at the 3'-CCA end [Brigotti, M., Carnicelli, D., Alvergna, P., Pallanca, A., Lorenzetti, R., Denaro, M., Sperti, S. and Montanaro, L. (1995) Biochem. J. 310, 249-253]. In the present study it is shown that tRNAs are involved in the up-regulation of all the cofactor-requiring RIPs up to now identified (agrostin, barley RIP, PAP and tritin, besides gelonin). Polyacrylamide gel electrophoresis shows that tRNA fractions with different mobilities stimulate different RIPs. With the identification of agrostin, the cofactor-requiring RIPs (italics) add to five out of a total of thirteen investigated: barley RIP, bryodin-R, gelonin, lychnin, momordin, momorcochin-S, PAP, saporin-6, tritin [Carnicelli, D., Brigotti, M., Montanaro, L. and Sperti, S. (1992) Biochem. Biophys. Res. Commun. 182, 579-582], agrostin, luffin, trichokirin and trichosanthin (present study).
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Affiliation(s)
- M Brigotti
- Dipartimento di Patologia sperimentale dell'Università di Bologna, Italy
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28
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Brigotti M, Carnicelli D, Alvergna P, Pallanca A, Lorenzetti R, Denaro M, Sperti S, Montanaro L. 3'-immature tRNA(Trp) is required for ribosome inactivation by gelonin,a plant RNA N-glycosidase. Biochem J 1995; 310 ( Pt 1):249-53. [PMID: 7646453 PMCID: PMC1135880 DOI: 10.1042/bj3100249] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Inactivation of ribosomes by gelonin, a ribosome-inactivating protein with RNA N-glycosidase activity on 28 S rRNA, requires macromolecular cofactors present in post-ribosomal supernatants. One of these cofactors has been purified from a rat liver extract and identified as an RNA about 70 nt long which in sequence analysis shows a high level of similarity with mammalian (bovine) tRNA(Trp). The pattern of the sequencing gel is consistent with the co-existence in the preparation of two 3'-immature tRNA(Trp) species, missing only A75, or both A75 and C74. In the presence of ATP, CTP and tRNA nucleotidyltransferase, the gelonin-stimulating RNA is a good acceptor of tryptophan. An oligodeoxynucleotide complementary to positions 55 to 72 of mammalian (bovine) tRNA(Trp) hybridizes with the gelonin-stimulating RNA as demonstrated by gel mobility shift and ribonuclease H digestion. The oligodeoxynucleotide-directed ribonuclease H treatment also abolishes the gelonin-promoting activity of crude preparations of RNA, giving strong evidence that the only active RNA is a tRNA(Trp)-like molecule.
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Affiliation(s)
- M Brigotti
- Dipartimento di Patologia sperimentale dell'Università di Bologna, Italy
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29
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30
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de Benito FM, Citores L, Iglesias R, Ferreras JM, Soriano F, Arias J, Méndez E, Girbés T. Ebulitins: a new family of type 1 ribosome-inactivating proteins (rRNA N-glycosidases) from leaves of Sambucus ebulus L. that coexist with the type 2 ribosome-inactivating protein ebulin 1. FEBS Lett 1995; 360:299-302. [PMID: 7883051 DOI: 10.1016/0014-5793(95)00130-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A new family of single chain (type 1) ribosome-inactivating proteins (RIPs), that we have named ebulitins, have been found in mature leaves of Sambucus ebulus L., a caprifoliaceae plant also known to contain a non-toxic two chain (type 2) RIP named ebulin I in its leaves. Ebulitins are basic proteins of M(r) 32,000, 29,000 and 29,000 for ebulitins alpha, beta and gamma, respectively. The simultaneous presence of different basic type 1 and acidic type 2 RIPs in the same plant and in the same tissue is described here for the first time and opens a new door in research into RIPs.
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Affiliation(s)
- F M de Benito
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Valladolid, Spain
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31
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Massiah AJ, Hartley MR. Wheat ribosome-inactivating proteins: seed and leaf forms with different specificities and cofactor requirements. PLANTA 1995; 197:633-640. [PMID: 8555963 DOI: 10.1007/bf00191571] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Distinct forms of ribosome-inactivating proteins were purified from wheat (Triticum aestivum L.) germ and leaves and termed tritin-S and tritin-L, respectively. These differ in size and charge and are antigenically unrelated. They are both RNA N-glycosidases which act on 26S rRNA in native yeast (Saccharomyces cerevisiae) ribosomes by the removal of A3024 located in a universally conserved sequence in domain VII which has previously been identified as the site of action of ricin A-chain. Tritin-S and tritin-L differ in both their ribosome substrate specificities and cofactor requirements. Tritin-S shows only barely detectable activity on ribosomes from the endosperm, its tissue of synthesis, whereas tritin-L is highly active on leaf ribosomes. Additionally, tritin-S is inactive on wheat germ, tobacco leaf and Escherichia coli ribosomes but active on rabbit reticulocyte and yeast ribosomes. Tritin-L is active on ribosomes from all of the above sources. Tritin-S, unlike tritin-L shows a marked requirement for ATP in its action.
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Affiliation(s)
- A J Massiah
- Department of Biological Sciences, University of Warwick, Coventry, West Midlands, UK
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32
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Arias FJ, Rojo MA, Ferreras JM, Iglesias R, Muñoz R, Soriano F, Méndez E, Barbieri L, Girbés T. Isolation and characterization of two new N-glycosidase type-1 ribosome-inactivating proteins, unrelated in amino-acid sequence, from Petrocoptis species. PLANTA 1994; 194:487-491. [PMID: 7528586 DOI: 10.1007/bf00714460] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Two new N-glycosidase type-1 ribosome-inactivating proteins (RIPs), denoted petroglaucin 1 and petrograndin, respectively, were isolated from the plants Petrocoptis glaucifolia (Lag.) Boiss sp. viscosa (Rothm.) Lainz and Petrocoptis grandiflora Rothm. These new RIPs do not share H2N-terminal amino-acid sequence homology with petroglaucin (now denoted as petroglaucin 2), the only other type-1 RIP to be isolated from P. glaucifolia (Arias et al. (1992) Planta 186, 532-540). Petroglaucin 1 shares amino-acid sequence homology with RIPs from Cucurbitaceae while petroglaucin 2 and petrograndin do so with saporins and dianthin 30 (Caryophyllaceae). The new RIPs strongly inhibited protein synthesis at subnanomolar concentrations in rabbit reticulocyte lysates and other eukaryotic cell-free systems, but they were inactive on bacterial ribosomes.
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Affiliation(s)
- F J Arias
- Departamento de Bioquímica, Biología Molecular y Fisiología, Facultad de Ciencias, Universidad de Valladolid, Spain
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33
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Barbieri L, Battelli MG, Stirpe F. Ribosome-inactivating proteins from plants. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1154:237-82. [PMID: 8280743 DOI: 10.1016/0304-4157(93)90002-6] [Citation(s) in RCA: 546] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- L Barbieri
- Dipartimento di Patologia Sperimentale, Università di Bologna, Italy
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34
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Abstract
Pokeweed antiviral protein (PAP) is a ribosome-inactivating protein (RIP) that inactivates ribosomes by the removal of a single adenine from ribosomal RNA. The studies summarized in our review concern the nature and application of this novel therapeutic agent. We describe how researchers continue to elucidate the structure and biologic activity of RIPs. Pokeweed antiviral protein is among the RIPs that have been conjugated to selective monoclonal antibodies for the treatment of several human cancers and viral diseases. Clinical trials using PAP immunotoxins for the treatment of leukemia have been particularly encouraging.
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Affiliation(s)
- J D Irvin
- Department of Chemistry, Southwest Texas State University, San Marcos 78666
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