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França TCC, Botelho FD, Drummond ML, LaPlante SR. Theoretical Investigation of Repurposed Drugs Potentially Capable of Binding to the Catalytic Site and the Secondary Binding Pocket of Subunit A of Ricin. ACS OMEGA 2022; 7:32805-32815. [PMID: 36120038 PMCID: PMC9476511 DOI: 10.1021/acsomega.2c04819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Recently, we reported a library of 82 compounds, selected from different databanks through virtual screening and docking studies, and pointed to 6 among them as potential repurposed dual binders to both the catalytic site and the secondary binding pockets of subunit A of ricin (RTA). Here, we report additional molecular modeling studies of an extended list of compounds from the original library. Rounds of flexible docking followed by molecular dynamics simulations and further rounds of MM-PBSA calculations using a more robust protocol, enabled a better investigation of the interactions of these compounds inside RTA, the elucidation of their dynamical behaviors, and updating the list of the most important residues for the ligand binding. Four compounds were pointed as potential repurposed ricin inhibitors that are worth being experimentally investigated.
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Affiliation(s)
- Tanos C. C. França
- Université
de Québec, INRS—Centre Armand-Frappier Santé
Biotechnologie, Laval, Quebec H7V 1B7, Canada
- Laboratory
of Molecular Modeling Applied to Chemical and Biological Defense, Military Institute of Engineering, Rio de Janeiro 22290-270, Brazil
- Department
of Chemistry, Faculty of Science, University
of Hradec Kralove, Rokitanskeho
62, Hradec Kralove 50003, Czech Republic
| | - Fernanda D. Botelho
- Laboratory
of Molecular Modeling Applied to Chemical and Biological Defense, Military Institute of Engineering, Rio de Janeiro 22290-270, Brazil
| | | | - Steven R. LaPlante
- Université
de Québec, INRS—Centre Armand-Frappier Santé
Biotechnologie, Laval, Quebec H7V 1B7, Canada
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Kumar A, Agarwal DK, Kumar S, Reddy YM, Chintagunta AD, Saritha K, Pal G, Kumar SJ. Nutraceuticals derived from seed storage proteins: Implications for health wellness. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2019. [DOI: 10.1016/j.bcab.2019.01.044] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Pandey SN, Iqbal N, Singh PK, Rastogi N, Kaur P, Sharma S, Singh TP. Binding and structural studies of the complexes of type 1 ribosome inactivating protein from Momordica balsamina
with uracil and uridine. Proteins 2018; 87:99-109. [DOI: 10.1002/prot.25584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/07/2018] [Accepted: 07/04/2018] [Indexed: 01/24/2023]
Affiliation(s)
- Sada Nand Pandey
- Department of Biophysics; All India Institute of Medical Sciences; New Delhi India
| | - Naseer Iqbal
- Department of Biophysics; All India Institute of Medical Sciences; New Delhi India
| | - Prashant K. Singh
- Department of Biophysics; All India Institute of Medical Sciences; New Delhi India
| | - Nilisha Rastogi
- Department of Biophysics; All India Institute of Medical Sciences; New Delhi India
| | - Punit Kaur
- Department of Biophysics; All India Institute of Medical Sciences; New Delhi India
| | - Sujata Sharma
- Department of Biophysics; All India Institute of Medical Sciences; New Delhi India
| | - Tej P. Singh
- Department of Biophysics; All India Institute of Medical Sciences; New Delhi India
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Akkouh O, Ng TB, Cheung RCF, Wong JH, Pan W, Ng CCW, Sha O, Shaw PC, Chan WY. Biological activities of ribosome-inactivating proteins and their possible applications as antimicrobial, anticancer, and anti-pest agents and in neuroscience research. Appl Microbiol Biotechnol 2015; 99:9847-63. [PMID: 26394859 DOI: 10.1007/s00253-015-6941-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/10/2015] [Accepted: 08/13/2015] [Indexed: 02/06/2023]
Abstract
Ribosome-inactivating proteins (RIPs) are enzymes which depurinate ribosomal RNA (rRNA), thus impeding the process of translation resulting in inhibition of protein synthesis. They are produced by various organisms including plants, fungi and bacteria. RIPs from plants are linked to plant defense due to their antiviral, antifungal, antibacterial, and insecticidal activities in which they can be applied in agriculture to combat microbial pathogens and pests. Their anticancer, antiviral, embryotoxic, and abortifacient properties may find medicinal applications. Besides, conjugation of RIPs with antibodies or other carriers to form immunotoxins has been found useful to research in neuroscience and anticancer therapy.
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Affiliation(s)
- Ouafae Akkouh
- Department of Biology and Medical Laboratory Research, Faculty of Technology, University of Applied Sciences Leiden, Zernikdreef 11, 2333 CK, Leiden, The Netherlands.
| | - Tzi Bun Ng
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
| | - Randy Chi Fai Cheung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
| | - Jack Ho Wong
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
| | - Wenliang Pan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
| | - Charlene Cheuk Wing Ng
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
| | - Ou Sha
- School of Medicine, Shenzhen University Health Science Centre, Shenzhen University, Shenzhen, China.
| | - Pang Chui Shaw
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
| | - Wai Yee Chan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
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5
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Domashevskiy AV, Goss DJ. Pokeweed antiviral protein, a ribosome inactivating protein: activity, inhibition and prospects. Toxins (Basel) 2015; 7:274-98. [PMID: 25635465 PMCID: PMC4344624 DOI: 10.3390/toxins7020274] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/07/2015] [Accepted: 01/23/2015] [Indexed: 01/30/2023] Open
Abstract
Viruses employ an array of elaborate strategies to overcome plant defense mechanisms and must adapt to the requirements of the host translational systems. Pokeweed antiviral protein (PAP) from Phytolacca americana is a ribosome inactivating protein (RIP) and is an RNA N-glycosidase that removes specific purine residues from the sarcin/ricin (S/R) loop of large rRNA, arresting protein synthesis at the translocation step. PAP is thought to play an important role in the plant's defense mechanism against foreign pathogens. This review focuses on the structure, function, and the relationship of PAP to other RIPs, discusses molecular aspects of PAP antiviral activity, the novel inhibition of this plant toxin by a virus counteraction-a peptide linked to the viral genome (VPg), and possible applications of RIP-conjugated immunotoxins in cancer therapeutics.
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MESH Headings
- Animals
- Binding Sites
- Endoribonucleases/chemistry
- Fungal Proteins/chemistry
- Genome, Viral
- Humans
- Protein Isoforms
- RNA Caps/chemistry
- RNA Caps/genetics
- RNA Caps/metabolism
- RNA, Plant/chemistry
- RNA, Plant/genetics
- RNA, Plant/metabolism
- RNA, Ribosomal/chemistry
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Viral/chemistry
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Ribosome Inactivating Proteins, Type 1/chemistry
- Ribosome Inactivating Proteins, Type 1/genetics
- Ribosome Inactivating Proteins, Type 1/metabolism
- Ribosome Inactivating Proteins, Type 1/pharmacology
- Ribosomes/chemistry
- Ribosomes/metabolism
- Ricin/chemistry
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Affiliation(s)
- Artem V Domashevskiy
- John Jay College of Criminal Justice, Department of Sciences, City University of New York, 524 West 59th Street, New York, NY 10019, USA.
| | - Dixie J Goss
- Department of Chemistry, Hunter College, City University of New York and the Graduate Center, 695 Park Avenue, New York, NY 10065, USA.
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Lee BG, Kim MK, Kim BW, Suh SW, Song HK. Structures of the ribosome-inactivating protein from barley seeds reveal a unique activation mechanism. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:1488-500. [PMID: 23090398 DOI: 10.1107/s0907444912037110] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 08/28/2012] [Indexed: 05/26/2023]
Abstract
Ribosome-inactivating protein (RIP), a defence protein found in various plants, possesses different chain architectures and activation mechanisms. The RIP from barley (bRIP) is a type I RIP and has sequence features that are divergent from those of type I and type II RIPs from dicotyledonous plants and even the type III RIP from maize. This study presents the first crystal structure of an RIP from a cereal crop, barley, in free, AMP-bound and adenine-bound states. For phasing, a codon-optimized synthetic brip1 gene was used and a vector was constructed to overexpress soluble bRIP fusion proteins; such expression has been verified in a number of cases. The overall structure of bRIP shows folding similar to that observed in other RIPs but also shows significant differences in specific regions, particularly in a switch region that undergoes a structural transition between a 3(10)-helix and a loop depending on the liganded state. The switch region is in a position equivalent to that of a proteolytically susceptible and putative ribosome-binding site in type III RIPs. Thus, the bRIP structure confirms the detailed enzymatic mechanism of this N-glycosidase and reveals a novel activation mechanism for type I RIPs from cereal crops.
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Affiliation(s)
- Byung-Gil Lee
- School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea
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7
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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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Lombardi A, Marshall RS, Savino C, Fabbrini MS, Ceriotti A. Type I Ribosome-Inactivating Proteins from Saponaria officinalis. TOXIC PLANT PROTEINS 2010. [DOI: 10.1007/978-3-642-12176-0_4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Sha O, Kwong WH, Pang Cho EY, Wai Yew DT, Ng TB. Different neuronal toxicity of single-chain ribosome-inactivating proteins on the rat retina. Toxicon 2008; 51:45-53. [PMID: 17889920 DOI: 10.1016/j.toxicon.2007.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Revised: 08/08/2007] [Accepted: 08/09/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To investigate the neurotoxicity of two structurally similar single chains of ribosome-inactivating proteins (RIPs): trichosanthin (TCS) and ricin A chain (RTA). METHODS TCS, RTA and Ricinus communis agglutinin (RCA, a multi-chain RIP for comparison) were separately injected into rat eyes. Saline was used as control. The data on cell counts, retinal thickness and histopathological scores were collected, and the TUNEL method (terminal deoxynucleotidyl transferase biotin-dUTP nick end labelling) was used to study the mode of cell death. RESULTS TCS caused distinct retinal changes at 1 nmol. Its toxic effects were most pronounced on the cells of the outer nuclear layer, less so on those of the inner nuclear layer, and little on the ganglion cells. Apoptosis was the predominant type of cell death induced by TCS. In contrast, RTA and RCA, both at 0.01 nmol, brought about acute retinal inflammation and necrosis. CONCLUSION TCS can eliminate specific retinal cells by apoptosis, while RTA and RCA cause retinitis. The B chain of type II RIPs is not obligatory for their neurotoxicity. The RIPs may be useful for creating retinal models and TCS may be useful for the chemical treatment of retinoblastoma.
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Affiliation(s)
- Ou Sha
- Department of Anatomy, Basic Medical Sciences Building, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
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10
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Zhang K, Xu J, Huang X, Wu L, Wen C, Hu Y, Su Y, Chen Y, Zhang Z. Trichosanthin down-regulated p210Bcr-Abl and enhanced imatinib-induced growth arrest in chronic myelogenous leukemia cell line K562. Cancer Chemother Pharmacol 2007; 60:581-7. [PMID: 17435997 DOI: 10.1007/s00280-007-0457-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Accepted: 03/04/2007] [Indexed: 11/28/2022]
Abstract
PURPOSE Trichosanthin (TCS), an active component extracted from the root tubers of traditional Chinese medical herb Tian-Hua-Fen of the Cucurbitaceae family, has long been used for medical purpose in China; there is increasing interest in developing TCS as cancer therapeutic agents. The present study was to investigate the growth arrest of K562 cells and its molecular mechanisms, which the drugs induced by TCS and the possible functional interaction of TCS with imatinib (STI571) to K562 cells. METHODS Trypan blue exclusive staining was used to access the cell growth inhibition; western blot was used to evaluate the p210(Bcr-Abl), phosphorylated tyrosine kinase (PTK), and some signaling molecules involving in cell proliferation and apoptosis in K562 cells. RESULTS TCS and imatinib inhibited K562 cells at a time- and dose-dependent manners, respectively; TCS down-regulated p210(Bcr-Abl) at a time- and dose-dependent manners; TCS synergistically enhanced imatinib-induced K562 cell growth arrest and down-regulation of p210(Bcr-Abl), PTK activities, procaspase-3, Hsp90,NF-kappaB and PKC. CONCLUSION The results suggest that TCS not only by itself involves but also synergizes activities of imatinib to induce K562 cell growth arrest, down-regulation of p210(Bcr-Abl) and its downstream signals and to stimulate the effect of the tyrosine kinase inhibition.
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Affiliation(s)
- Kunzhong Zhang
- Institute of Clinical Pharmacology, School of Pharmacy, Fujian Medical University, Fujian 350004, People's Republic China
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11
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An Q, Wei S, Mu S, Zhang X, Lei Y, Zhang W, Jia N, Cheng X, Fan A, Li Z, Xu Z. Mapping the antigenic determinants and reducing the immunogenicity of trichosanthin by site-directed mutagenesis. J Biomed Sci 2006; 13:637-43. [PMID: 16977428 DOI: 10.1007/s11373-006-9095-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Accepted: 06/01/2006] [Indexed: 11/26/2022] Open
Abstract
Trichosanthin (TCS) is a type I ribosome-inactivating protein (RIP) possessing multiple pharmacological properties. One of its interesting properties is to inhibit human immunodeficiency virus (HIV) replication but its strong immunogenicity has limited the repeated clinical administration. To map the antigenic determinants and reduce the immunogenicity of TCS, two potential antigenic sites (YFF81-83 and KR173-174) were identified by computer modeling, and then three TCS mutants namely TCS(YFF81-83ACS), TCS(KR173-174CG), and TCS(YFF-KR) were constructed by site-directed mutagenesis. The RI activity and DNase-like activity of the three constructed TCS mutants were similar to natural TCS but with much lower immunogenicity. Results suggested that the two selected sites are all located at or near the antigenic determinants of TCS. In toxicity studies, the LD(50) of the three TCS mutants was not different from natural TCS. These findings would be useful in designing a better therapeutic agent for AIDS.
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Affiliation(s)
- Qunxing An
- Department of Microbiology, Fourth Medical University of PLA, Xi'an, 710032, China
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12
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Zhang XY, Wu Y, Yan JY, Gao Y, Wang Y, Mi SL, An CC. Y55 and D78 are crucial amino acid residues of a new IgE epitope on trichosanthin. Biochem Biophys Res Commun 2006; 343:1251-6. [PMID: 16581017 DOI: 10.1016/j.bbrc.2006.03.097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Accepted: 03/16/2006] [Indexed: 10/24/2022]
Abstract
Trichosanthin (TCS) possesses many biological and pharmaceutical activities, but its strong immunogenicity limits its clinical application. To reduce the immunogenicity of TCS, we modified the reported method for the prediction of antigenic site and identified two crucial amino acid residues (Y55 and D78) for a new epitope. We mutated these two residues into glycine and serine, respectively, and obtained three mutants, Y55G, D78S, and Y55G/D78S. These mutants induced less amount of Ig and IgG antibodies in C57BL/6J mice than wild-type TCS (wTCS) (p<0.01) and almost lost the ability to induce IgE antibody production. The mutants stimulated fewer TCS-specific B cells in C57BL/6J mice than wTCS (p<0.01). Compared with wTCS, Y55G, D78S, and Y55G/D78S lost 26.9%, 17.9%, and 98.7% specific binding ability to anti-TCS monoclonal antibody TCS4E9, respectively. These mutants still retained RNA N-glycosidase activity. In conclusion, Y55 and D78 are two crucial amino acid residues of a new IgE epitope on TCS, and their mutation reduces the immunogenicity of TCS, but still retained the enzymatic activity.
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Affiliation(s)
- Xin-Yue Zhang
- The National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, PR China
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Shaw PC, Lee KM, Wong KB. Recent advances in trichosanthin, a ribosome-inactivating protein with multiple pharmacological properties. Toxicon 2005; 45:683-9. [PMID: 15804517 DOI: 10.1016/j.toxicon.2004.12.024] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Accepted: 12/24/2004] [Indexed: 11/22/2022]
Abstract
Trichosanthin (TCS), a ribosome-inactivating protein extracted from the root tuber of Chinese medicinal herb Trichosanthes kirilowii Maximowicz, has multiple pharmacological properties including abortifacient, anti-tumor and anti-HIV. It is traditionally used to induce abortion but its antigenicity and short plasma half-life have limited the repeated clinical administration. In this review, work to locating antigenic sites and prolonging plasma half-life are discussed. Studies on structure-function relationship and mechanism of cell entry are also covered. Recently, TCS has been found to induce apoptosis, enhance the action of chemokines and inhibit HIV-1 integrase. These findings give new insights on the pharmacological properties of TCS and other members of ribosome-inactivating proteins.
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Affiliation(s)
- Pang-Chui Shaw
- Department of Biochemistry, Centre for Protein Science and Crystallography, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
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Kurinov IV, Uckun FM. High resolution X-ray structure of potent anti-HIV pokeweed antiviral protein-III. Biochem Pharmacol 2003; 65:1709-17. [PMID: 12754107 DOI: 10.1016/s0006-2952(03)00144-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pokeweed antiviral protein III (PAP-III), a naturally occurring protein isolated from late summer leaves of the pokeweed plant (Phytolacca americana), has potent anti-HIV activity by an as yet undetermined molecular mechanism. PAP-III belongs to a family of ribosome-inactivating proteins that catalytically deadenylate ribosomal and viral RNA. The chemical modification of PAP-III by reductive methylation of its lysine residues significantly improved the crystal quality for X-ray diffraction studies. Trigonal crystals of the modified PAP-III, with unit cell parameters a=b=80.47A, c=76.21A, were obtained using 30% PEG400 as the precipitant. These crystals contained one enzyme molecule per asymmetric unit and diffracted up to 1.5A, when exposed to a synchrotron source. Here we report the X-ray crystal structure of PAP-III at 1.6A resolution, which was solved by molecular replacement using the homology model of PAP-III as a search model. The fold typical of other ribosome-inactivating proteins is conserved, despite several differences on the surface and in the loop regions. Residues Tyr(69), Tyr(117), Glu(172), and Arg(175) are expected to define the active site of PAP-III. Molecular modeling studies of the interactions of PAP-III and PAP-I with a single-stranded RNA heptamer predicted a more potent anti-HIV activity for PAP-III due to its unique surface topology and more favorable charge distribution in its 20A-long RNA binding active center cleft. In accordance with the predictions of the modeling studies, PAP-III was more potent than PAP-I in depurinating HIV-1 RNA.
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Affiliation(s)
- Igor V Kurinov
- The Biotherapy and Drug Discovery Program, Parker Hughes Cancer Center, 2699 Patton Road, St. Paul, MN 55113, USA
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Shaw PC, Wong KB, Chan DSB, Williams RL. Structural basis for the interaction of [E160A-E189A]-trichosanthin with adenine. Toxicon 2003; 41:575-81. [PMID: 12676436 DOI: 10.1016/s0041-0101(02)00387-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Trichosanthin is a ribosome-inactivating protein that cleaves specifically the N-glycosidic bond of A-4324 of 28S rRNA. Trichosanthin and its variant [E160A-E189A]-trichosanthin were found to bind an adenine base with a K(d) value of approximately 0.2mM. To determine how this doubly mutated variant of trichosanthin interacts with adenine, the co-crystal structure of [E160A-E189A]-trichosanthin and adenine was resolved to 0.193nm which revealed that the active site conformation of the doubly mutated variant is isomorphous to wild-type trichosanthin. Water molecules were found at locations corresponding to the eliminated side chain of Glu-160 and Glu-189. On the other hand, the adenine base interacted with [E160A-E189A]-trichosanthin in a manner similar to that in wild-type trichosanthin. Our structural analysis illustrates that Glu-160 and Glu-189 in trichosanthin do not play an important role in maintaining the active site conformation and binding adenine, an essential step for substrate-enzyme interaction. On the other hand, removal of two glutamate residues changed a large patch of negatively charged surface to a positive charge, which may account for the destabilization of the oxocarbenium-like transition-state and the significant decrease in ribosome-inactivating activity in [E160A-E189A]-trichosanthin.
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Affiliation(s)
- Pang-Chui Shaw
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, People's Republic of China.
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16
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Lu Y, Xia X, Sui S. The interaction of trichosanthin with supported phospholipid membranes studied by surface plasmon resonance. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1512:308-16. [PMID: 11406108 DOI: 10.1016/s0005-2736(01)00334-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Trichosanthin (TCS) is a toxic protein isolated from a Chinese herbal medicine, the root tuber of Trichosanthes kirilowii Maximowicz of the Curcurbitaceae family. It is now used in China to terminate early and mid-trimester pregnancies. The ribosome inactivating property is thought to be account for its toxicity; it can inactivate the eukaryotic ribosome through its RNA N-glycosidase activity. The interactions of TCS with biological membrane is thought to be essential for its physiological effect, for it must get across the membrane before it can enter the cytoplasm and exert its RIP function. In the present work, the interaction of TCS with supported phospholipid monolayers is studied by surface plasmon resonance. The results show that electrostatic forces dominate the interaction between TCS and negatively charged phospholipid containing membranes under acid condition and that both the pH value and the ionic strength can influence its binding. It is proposed that, besides electrostatic forces, hydrophobic interaction may also be involved in the binding process.
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Affiliation(s)
- Y Lu
- Department of Biological Sciences and Biotechnology, State-Key Laboratory of Biomembrane, Tsinghua University, 100084, Beijing, PR China
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17
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Chan SH, Shaw PC, Mulot SF, Xu LH, Chan WL, Tam SC, Wong KB. Engineering of a mini-trichosanthin that has lower antigenicity by deleting its C-terminal amino acid residues. Biochem Biophys Res Commun 2000; 270:279-85. [PMID: 10733940 DOI: 10.1006/bbrc.2000.2395] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Trichosanthin is a ribosome-inactivating protein that possesses antitumor and antiviral activities. Clinical trials of trichosanthin on AIDS patients, however, elicit anaphylactic reactions. To reduce the antigenicity of trichosanthin as a drug while preserving its biological activity, the C-terminal domain (residues 203 to 247), which contains a putative antigenic site, was systemically deleted. We have found that the minimum length of trichosanthin that can fold into an active conformation is residue 1 to 240. The mini-trichosanthin (C7) generated by deleting the last seven C-terminal amino acid residues has 2.7-fold decrease in antigenicity, 10-fold reduction in in vitro ribosome-inactivation activity, and in vivo cytotoxicity toward K562 cells, and 2-fold reduction in abortificient activity. Structural analyses of C7 indicate decrease in the helix content, increased exposure of Trp192, and lower thermodynamic stability. The deletion of the C-terminal residues (Leu241 to Ala247) probably perturbs local structure of the C-terminal antigenic epitope that results in the decrease in antigenicity and activities of C7.
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Affiliation(s)
- S H Chan
- Department of Biochemistry, Department of Physiology, Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
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18
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Gu YJ, Xia ZX. Crystal structures of the complexes of trichosanthin with four substrate analogs and catalytic mechanism of RNA N-glycosidase. Proteins 2000. [DOI: 10.1002/(sici)1097-0134(20000401)39:1<37::aid-prot4>3.0.co;2-g] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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19
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Abstract
Many proteins exhibit both a water-soluble and a membrane-bound state. The proteins in the membrane-bound state obtain a distinct structure from that in the bulk, which exists in many important biological processes. In the present paper we would stress that the variation of the physical chemistry properties of the microenvironment adjacent to the membrane-surface region play an important role in the process of the membrane-induced conformational changes of the proteins.
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Affiliation(s)
- S F Sui
- Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, People's Republic of China.
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20
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Savino C, Federici L, Ippoliti R, Lendaro E, Tsernoglou D. The crystal structure of saporin SO6 from Saponaria officinalis and its interaction with the ribosome. FEBS Lett 2000; 470:239-43. [PMID: 10745075 DOI: 10.1016/s0014-5793(00)01325-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The 2.0 A resolution crystal structure of the ribosome inactivating protein saporin (isoform 6) from seeds of Saponaria officinalis is presented. The fold typical of other plant toxins is conserved, despite some differences in the loop regions. The loop between strands beta7 and beta8 in the C-terminal region which spans over the active site cleft appears shorter in saporin, suggesting an easier access to the substrate. Furthermore we investigated the molecular interaction between saporin and the yeast ribosome by differential chemical modifications. A contact surface inside the C-terminal region of saporin has been identified. Structural comparison between saporin and other ribosome inactivating proteins reveals that this region is conserved and represents a peculiar motif involved in ribosome recognition.
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Affiliation(s)
- C Savino
- Department of Biochemical Sciences and CNR Centre for Molecular Biology, University of Rome 'La Sapienza', Piazzale Aldo Moro 5, 00185, Rome, Italy
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21
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Xia X, Wang S, Luo J, Wong RNS, Sui S. Trichosanthin can spontaneously penetrate phospholipid monolayer under acid condition. ACTA ACUST UNITED AC 1999. [DOI: 10.1007/bf02886348] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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22
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Huang PL, Sun Y, Chen HC, Kung HF, Lee-Huang S. Proteolytic fragments of anti-HIV and anti-tumor proteins MAP30 and GAP31 are biologically active. Biochem Biophys Res Commun 1999; 262:615-23. [PMID: 10471373 DOI: 10.1006/bbrc.1999.1213] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We analyzed the structural and functional organization of anti-HIV and anti-tumor proteins MAP30 and GAP31 by limited proteolysis with endopeptidases Lys-C and Glu-C (V8). MAP30 and GAP31 are resistant to proteolytic digestion under conditions of as much as 5% (w/w) proteases. In the presence of 10% (w/w) protease, the central regions of the proteins are still resistant to proteolysis, whereas the N- and C-termini are accessible. Peptide fragments were purified by FPLC on Superdex 75 columns, characterized by gel electrophoresis, identified by amino acid sequencing, and analyzed for anti-HIV, anti-tumor, and other biochemical activities. We report here that limited proteolysis yields biologically active fragments of both MAP30 and GAP31. These fragments are active against HIV-1 and tumor cells with EC(50)s in the sub-nanomolar ranges, 0.2-0.4 nM. At the dose levels used in the assays, little cytotoxicity to normal cells was observed. In addition, these fragments remain fully active in HIV-integrase inhibition and HIV-LTR topological inactivation, but not ribosome inactivation. These results demonstrate that the antiviral and anti-tumor activities of MAP30 and GAP31 are independent of ribosome inactivation activity. In addition, we demonstrate that portions of the N- and C-termini are not essential for antiviral and anti-tumor activities, but do appear to be required for ribosome inactivation. These results may provide novel strategies for rational design and targeted development of mimetic antiviral and anti-tumor therapeutics.
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Affiliation(s)
- P L Huang
- American Biosciences, New York, New York, 10021, USA
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23
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Chan WL, Shaw PC, Li XB, Xu QF, He XH, Tam SC. Lowering of trichosanthin immunogenicity by site-specific coupling to dextran. Biochem Pharmacol 1999; 57:927-34. [PMID: 10086327 DOI: 10.1016/s0006-2952(98)00364-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Trichosanthin is a type I ribosome-inactivating protein possessing a broad spectrum of biological and pharmacological activities. Therapeutic use of this compound is hampered by its immunogenicity. It was shown earlier that coupling of dextran to trichosanthin can increase plasma half-life and reduce antigenicity. However, the site where dextran attaches to trichosanthin cannot be controlled; ideally, it should be at or near the antigenic determinant. The present study attempted to couple dextran to trichosanthin at a potential antigenic site. By site-directed mutagenesis, two sites, R29 and K173, were replaced by cysteine, and dextran was coupled to the newly created cysteine residues. The dextran-trichosanthin complex retained 50% of abortifacient activity and had a mean residence time in rats 27-fold longer than natural trichosanthin. Acute hypersensitivity reaction in guinea pigs was reduced greatly after coupling of K173C (a trichosanthin mutant with lysine-173 replaced by cysteine) to dextran. Compared with natural trichosanthin, dextran-K173C had a decrease in IgG and IgE response, whereas the coupling of R29C (a trichosanthin mutant with arginine-29 replaced by cysteine) to dextran did not show significant reduction of immunogenicity. This suggests that K173 but not R29 is located at or near an antigenic determinant. This study has demonstrated an alternative approach for mapping of antigenic determinants. The information obtained is also useful in producing an improved trichosanthin derivative for therapeutic use.
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Affiliation(s)
- W L Chan
- Department of Physiology, The Chinese University of Hong Kong, Shatin, NT
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24
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Poyet JL, Hoeveler A, Jongeneel CV. Analysis of active site residues of the antiviral protein from summer leaves from Phytolacca americana by site-directed mutagenesis. Biochem Biophys Res Commun 1998; 253:582-7. [PMID: 9918771 DOI: 10.1006/bbrc.1998.9815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The summer leaf isoform of the pokeweed (Phytolacca americana) antiviral protein, PAP II, was produced in high yields from inclusion bodies in recombinant E. coli. On the basis of its sequence similarity with the spring leaf isoform (PAP I) and with the A chain of ricin, a three-dimensional model of the protein was constructed as an aid in the design of active site mutants. PAP II variants mutated in residues Asp 88 (D88N), Tyr 117 (Y117S), Glu 172 (E172Q), Arg 175 (R175H) and a combination of Asp 88 and Arg 175 (D88N/R175H) were produced in E. coli and assayed for their ability to inhibit protein synthesis in a rabbit reticulocyte lysate. All of these mutations had effects deleterious to the enzymatic activity of PAP II. The results were interpreted in the light of three reaction mechanisms proposed for ribosome-inactivating proteins (RIPs). We conclude that none of the proposed mechanisms is entirely consistent with the data presented here.
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Affiliation(s)
- J L Poyet
- Laboratoire de Biochimie et de Biologie Moléculaire, UFR des Sciences et des Techniques, Besançon, France
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25
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Mulot S, Chung KK, Li XB, Wong CC, Ng TB, Shaw PC. The antigenic sites of trichosanthin, a ribosome-inactivating protein with multiple pharmacological properties. Life Sci 1998; 61:2291-303. [PMID: 9408052 DOI: 10.1016/s0024-3205(97)00933-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Trichosanthin (TCS) fragments were produced by Tn1000 deletion mutagenesis and by cyanogen bromide (CNBr) cleavage and their immunoreactivity was examined by incubating with various antibodies. Twelve C-terminally truncated TCS variants were successfully synthesized under the control of a T7 RNA driven promoter. The smallest antigenic fragment mapped corresponded to the N-terminal 20 amino acids (aa). Six CNBr fragments of TCS were created and identified by electrospray mass spectrometry and N-terminal sequencing. Three antigenic fragments corresponding to aa 1-72, 101-152 and 153-246, respectively were mapped. Fragments corresponding to aa 1-72 and 153-246 were immunoreactive to the same monoclonal antibody showing they are components of a discontinuous epitope. On the other hand, the fragment containing aa 73-100 was not detected by any of the antibodies used.
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Affiliation(s)
- S Mulot
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT
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26
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Shaw PC, Mulot S, Ma SK, Xu QF, Yao HB, Wu S, Lu XH, Dong YC. Structure/function relationship study of Tyr14 and Arg22 in trichosanthin, a ribosome-inactivating protein. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 245:423-7. [PMID: 9151974 DOI: 10.1111/j.1432-1033.1997.00423.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Amino acids Tyr14 and Arg22 in trichosanthin are residues on helix A1 close to the active-site cleft. They are invariant in various type-I and type-II ribosome-inactivating proteins. In this study, Tyr14 was changed to Phe and Arg22 to Lys and Leu. Modified proteins were purified, and activities compared by assaying their median inhibitory concentration (ID50) on a rabbit-reticulocyte-lysate protein-synthesis system. While the ID50 of wild-type trichosanthin was 0.02 nM, those for [Phe14], [Lys22], [Leu22] and [Phe14, Leu22]trichosanthin were 0.10, 0.03, 0.25 and 0.15 nM, respectively. Therefore, compared with Tyr14, Arg22 appears to play a more important role in trichosanthin. Structural studies on [Leu22]trichosanthin showed that two water molecules occupy the space left by the side chain of Arg22, and hydrogen bonds exist between these water molecules and nearby residues to retain the conformation. The use of intermolecular rather than intramolecular hydrogen bonds may have an adverse effect on stability or folding of the protein and results in a mild decrease in activity.
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Affiliation(s)
- P C Shaw
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin
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Kohno T, Senda T, Narumi H, Kimura S, Mitsui Y. Crystallization and preliminary crystallographic analysis of recombinant abrin-a A-chain with ribosome inactivating activity. Proteins 1995; 23:126-7. [PMID: 8539247 DOI: 10.1002/prot.340230116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Crystals have been obtained for a recombinant abrin-a A-chain produced by E. coli. The crystals were grown using PEG6000 as the precipitating agent. The crystals belong to an orthrhombic space group (P2(1)2(1)2(1)) and diffract to 1.7 A.
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Affiliation(s)
- T Kohno
- Department of BioEngineering, Nagaoka University of Technology, Niigata, Japan
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29
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Bravi G, Legname G, Chan AW. Substrate recognition by ribosome-inactivating protein studied by molecular modeling and molecular electrostatic potentials. JOURNAL OF MOLECULAR GRAPHICS 1995; 13:83-8, 109. [PMID: 7619790 DOI: 10.1016/0263-7855(94)00014-j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A computer model of dianthin 30, a type 1 ribosome-inactivating protein (RIP), is constructed by homology modeling using two known X-ray structures; a type 1 RIP, pokeweed antiviral protein (PAP), and chain A of a type 2 RIP, ricin. The 3D structure is refined by molecular dynamics and its binding site compared with those of PAP and ricin using molecular electrostatic potential mapping. The differences in the maps obtained clearly show how, despite the similarity of the topology of the binding site, differences in electrostatic potential can account for the experimentally observed differences in substrate recognition and binding. This demonstrates the potential of these techniques for guiding further experimental analyses.
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Affiliation(s)
- G Bravi
- Italfarmaco Research Center, Cinisello Balsamo, Italy
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