1
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Akinniyi G, Akinboye AJ, Yang I, Lee JG. Plant proteins, peptides, and non-protein amino acids: Toxicity, sources, and analysis. Heliyon 2024; 10:e34890. [PMID: 39145010 PMCID: PMC11320209 DOI: 10.1016/j.heliyon.2024.e34890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 07/17/2024] [Accepted: 07/18/2024] [Indexed: 08/16/2024] Open
Abstract
Plants have evolved various mechanisms to synthesize diverse range of substances that contribute to their survival against pests, pathogens, predators, and adverse environmental conditions. Although several plant metabolites possess therapeutic potential, some can be potentially harmful to human and animal health when consumed in large proportion. Proteins, peptides, and non-protein amino acids are products of plant biochemical pathways with proven beneficial and nutritional effects. Despite these benefits, the in vivo toxicities associated with certain plant-derived proteins, peptides, and non-protein amino acids pose a significant risk to humans and animals. Symptoms of poisoning include nausea, vomiting, diarrhea, hair and weight loss, goiter, cataracts, and infertility. Even though plant processing methods such as soaking and drying can reduce the amount of toxin contained in plants, complete riddance is often impossible. As such, food regulatory bodies need to prevent uncontrolled consumption of the listed and many other toxin-containing plant species to keep the public safe. For this purpose, this review collates crucial insights into the sources, and in vivo toxicity associated with certain plant-derived proteins, peptides, and non-protein amino acids that have the clear potential to adversely affect human health. Additionally, this review provides information on analytical methods suitable for the detection of these substances in plants.
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Affiliation(s)
- Ganiyu Akinniyi
- Department of Convergence Study on the Ocean Science and Technology, National Korea Maritime and Ocean University, Busan 49112, South Korea
| | - Adebayo J. Akinboye
- Department of Food Science and Biotechnology, Seoul National University of Science and Technology, Nowon-gu, Seoul 01811, South Korea
| | - Inho Yang
- Department of Convergence Study on the Ocean Science and Technology, National Korea Maritime and Ocean University, Busan 49112, South Korea
| | - Joon-Goo Lee
- Department of Food Science and Biotechnology, Seoul National University of Science and Technology, Nowon-gu, Seoul 01811, South Korea
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2
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Tran GH, Tran TH, Pham SH, Xuan HL, Dang TT. Cyclotides: The next generation in biopesticide development for eco-friendly agriculture. J Pept Sci 2024; 30:e3570. [PMID: 38317283 DOI: 10.1002/psc.3570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/09/2024] [Accepted: 01/12/2024] [Indexed: 02/07/2024]
Abstract
Chemical pesticides remain the predominant method for pest management in numerous countries. Given the current landscape of agriculture, the development of biopesticides has become increasingly crucial. The strategy empowers farmers to efficiently manage pests and diseases, while prioritizing minimal adverse effects on the environment and human health, hence fostering sustainable management. In recent years, there has been a growing interest and optimism surrounding the utilization of peptide biopesticides for crop protection. These sustainable and environmentally friendly substances have been recognized as viable alternatives to synthetic pesticides due to their outstanding environmental compatibility and efficacy. Numerous studies have been conducted to synthesize and identify peptides that exhibit activity against significant plant pathogens. One of the peptide classes is cyclotides, which are cyclic cysteine-rich peptides renowned for their wide range of sequences and functions. In this review, we conducted a comprehensive analysis of cyclotides, focusing on their structural attributes, developmental history, significant biological functions in crop protection, techniques for identification and investigation, and the application of biotechnology to enhance cyclotide synthesis. The objective is to emphasize the considerable potential of cyclotides as the next generation of plant protection agents on the global scale.
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Affiliation(s)
- Gia-Hoa Tran
- Institute of Applied Materials Science, Vietnam Academy of Science and Technology, Ho Chi Minh City, Viet Nam
- Institute of Biotechnology and Food Technology, Industrial University of Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Thi-Huyen Tran
- Institute of Biotechnology and Food Technology, Industrial University of Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Son H Pham
- Institute of Applied Materials Science, Vietnam Academy of Science and Technology, Ho Chi Minh City, Viet Nam
| | - Huy Luong Xuan
- Faculty of Pharmacy, PHENIKAA University, Hanoi, Vietnam
| | - Tien T Dang
- Institute of Applied Materials Science, Vietnam Academy of Science and Technology, Ho Chi Minh City, Viet Nam
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Viet Nam
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3
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Bajpai A, Jackson MA, Huang YH, Yap K, Du Q, Chau TCY, Craik DJ, Gilding EK. Nematicidal Activity of Cyclotides: Toxicity Against Caenorhabditis elegans. JOURNAL OF NATURAL PRODUCTS 2023; 86:1222-1229. [PMID: 37099442 DOI: 10.1021/acs.jnatprod.2c01124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Cyclotides are a unique family of stable and cyclic mini-proteins found in plants that have nematicidal and anthelmintic activities. They are distributed across the Rubiaceae, Violaceae, Fabaceae, Cucurbitaceae, and Solanaceae plant families, where they are posited to act as protective agents against pests. In this study, we tested the nematicidal properties of extracts from four major cyclotide-producing plants, Oldenlandia affinis, Clitoria ternatea, Viola odorata, and Hybanthus enneaspermus, against the free-living model nematode Caenorhabditis elegans. We evaluated the nematicidal activity of the cyclotides kalata B1, cycloviolacin O2, and hyen D present in these extracts and found them to be active against the larvae of C. elegans. Both the plant extracts and isolated cyclotides exerted dose-dependent toxicity on the first-stage larvae of C. elegans. Isolated cyclotides caused death or damage upon interacting with the worms' mouth, pharynx, and midgut or membrane. Cycloviolacin O2 and hyen D produced bubble-like structures around the C. elegans membrane, termed blebs, implicating membrane disruption causing toxicity and death. All tested cyclotides lost their toxicity when the hydrophobic patches present on them were disrupted via a single-point mutation. The present results provide a facile assay design to measure and explore the nematicidal activities of plant extracts and purified cyclotides on C. elegans.
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Affiliation(s)
- Abhishek Bajpai
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Mark A Jackson
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Yen-Hua Huang
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Kuok Yap
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Qingdan Du
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Tevin Chui-Ying Chau
- ACRF Cancer Biology Imaging Facility, Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Edward K Gilding
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
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4
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Aqueous Self-assembly of Extracted Cyclotides from Viola odorata into Novel Stable Supramolecular Structures. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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5
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Dang TT, Huang YH, Ott S, Harvey PJ, Gilding EK, Tombling BJ, Chan LY, Kaas Q, Claridge-Chang A, Craik DJ. The acyclotide ribe 31 from Rinorea bengalensis has selective cytotoxicity and potent insecticidal properties in Drosophila. J Biol Chem 2022; 298:102413. [PMID: 36007611 PMCID: PMC9513267 DOI: 10.1016/j.jbc.2022.102413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022] Open
Abstract
Cyclotides and acyclic versions of cyclotides (acyclotides) are peptides involved in plant defense. These peptides contain a cystine knot motif formed by three interlocked disulfide bonds, with the main difference between the two classes being the presence or absence of a cyclic backbone, respectively. The insecticidal activity of cyclotides is well documented, but no study to date explores the insecticidal activity of acyclotides. Here, we present the first in vivo evaluation of the insecticidal activity of acyclotides from Rinorea bengalensis on the vinegar fly Drosophila melanogaster. Of a group of structurally comparable acyclotides, ribe 31 showed the most potent toxicity when fed to D. melanogaster. We screened a range of acyclotides and cyclotides and found their toxicity toward human red blood cells was substantially lower than toward insect cells, highlighting their selectivity and potential for use as bioinsecticides. Our confocal microscopy experiments indicated their cytotoxicity is likely mediated via membrane disruption. Furthermore, our surface plasmon resonance studies suggested ribe 31 preferentially binds to membranes containing phospholipids with phosphatidyl-ethanolamine headgroups. Despite having an acyclic backbone, we determined the three-dimensional NMR solution structure of ribe 31 is similar to that of cyclotides. In summary, our results suggest that, with further optimization, ribe 31 could have applications as an insecticide due to its potent in vivo activity against D. melanogaster. More broadly, this work advances the field by demonstrating that acyclotides are more common than previously thought, have potent insecticidal activity, and have the advantage of potentially being more easily manufactured than cyclotides.
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Affiliation(s)
- Tien T Dang
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Yen-Hua Huang
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Stanislav Ott
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, 169857
| | - Peta J Harvey
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Edward K Gilding
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Benjamin J Tombling
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Lai Y Chan
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Adam Claridge-Chang
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, 169857; Institute for Molecular and Cell Biology, A*STAR, Singapore, 138673; Department of Physiology, National University of Singapore, Singapore, 117593
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia.
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6
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Wei DX, Zhang XW. Biosynthesis, Bioactivity, Biosafety and Applications of Antimicrobial Peptides for Human Health. BIOSAFETY AND HEALTH 2022. [DOI: 10.1016/j.bsheal.2022.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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7
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Rajendran S, Slazak B, Mohotti S, Strömstedt AA, Göransson U, Hettiarachchi CM, Gunasekera S. Tropical vibes from Sri Lanka - cyclotides from Viola betonicifolia by transcriptome and mass spectrometry analysis. PHYTOCHEMISTRY 2021; 187:112749. [PMID: 33932786 DOI: 10.1016/j.phytochem.2021.112749] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 03/19/2021] [Accepted: 03/20/2021] [Indexed: 06/12/2023]
Abstract
Cyclotides are an extremely stable class of peptides, ubiquitously distributed in Violaceae. The aim of the present study was to investigate the presence of cyclotides in Sri Lankan Violaceae plants, using combined tools of transcriptomics and mass spectrometry. New cyclotides were discovered for the first time in the wild flora of Sri Lanka, within Viola betonicifolia, a plant used in traditional medicine as an antimicrobial. Plant extracts prepared in small scale from Viola betonicifolia were first subjected to LC-MS analysis. Subsequent transcriptome de novo sequencing of Viola betonicifolia uncovered 25 new (vibe 1-25) and three known (varv A/kalata S, viba 17, viba 11) peptide sequences from Möbius and bracelet cyclotide subfamilies as well as hybrid cyclotides. Among the transcripts, putative linear acyclotide sequences (vibe 4, vibe 10, vibe 11 and vibe 22) that lack a conserved asparagine or aspartic acid vital for cyclisation were also present. Four asparagine endopeptidases (AEPs), VbAEP1-4 were found within the Viola betonicifolia transcriptome, including a peptide asparaginyl ligase (PAL), potentially involved in cyclotide backbone cyclisation, showing >93% sequence homology to Viola yedoensis peptide asparaginyl ligases, VyPALs. In addition, we identified two protein disulfide isomerases (PDIs), VbPDI1-2, likely involved in cyclotide oxidative folding, having high sequence homology (>74%) with previously reported Rubiaceae and Violaceae PDIs. The current study highlights the ubiquity of cyclotides in Violaceae as well as the utility of transcriptomic analysis for cyclotides and their putative processing enzyme discovery. The high variability of cyclotide sequences in terms of loop sizes and residues in V. betonicifolia showcase the cyclotide structure as an adaptable scaffold as well as their importance as a combinatorial library, implicated in plant defense.
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Affiliation(s)
- Sanjeevan Rajendran
- Pharmacognosy, Department of Pharmaceutical Biosciences, Uppsala University, 751 23, Uppsala, Sweden; Department of Chemistry, Faculty of Science, University of Colombo, Thurston Rd, Colombo 03, Sri Lanka
| | - Blazej Slazak
- Pharmacognosy, Department of Pharmaceutical Biosciences, Uppsala University, 751 23, Uppsala, Sweden; W. Szafer Institute of Botany, Polish Academy of Science, 46 Lubicz St., 31-512, Cracow, Poland
| | - Supun Mohotti
- Department of Chemistry, Faculty of Science, University of Colombo, Thurston Rd, Colombo 03, Sri Lanka
| | - Adam A Strömstedt
- Pharmacognosy, Department of Pharmaceutical Biosciences, Uppsala University, 751 23, Uppsala, Sweden
| | - Ulf Göransson
- Pharmacognosy, Department of Pharmaceutical Biosciences, Uppsala University, 751 23, Uppsala, Sweden
| | - Chamari M Hettiarachchi
- Department of Chemistry, Faculty of Science, University of Colombo, Thurston Rd, Colombo 03, Sri Lanka
| | - Sunithi Gunasekera
- Pharmacognosy, Department of Pharmaceutical Biosciences, Uppsala University, 751 23, Uppsala, Sweden.
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8
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Iannetta AA, Rogers HT, Al-Mohanna T, O'Brien JN, Wommack AJ, Popescu SC, Hicks LM. Profiling thimet oligopeptidase-mediated proteolysis in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:336-350. [PMID: 33481299 DOI: 10.1111/tpj.15165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
Protein homeostasis (proteostasis) is crucial for proper cellular function, including the production of peptides with biological functions through controlled proteolysis. Proteostasis has roles in maintenance of cellular functions and plant interactions with the environment under physiological conditions. Plant stress continues to reduce agricultural yields causing substantial economic losses; thus, it is critical to understand how plants perceive stress signals to elicit responses for survival. As previously shown in Arabidopsis thaliana, thimet oligopeptidases (TOPs) TOP1 (also referred to as organellar oligopeptidase) and TOP2 (also referred to as cytosolic oligopeptidase) are essential components in plant response to pathogens, but further characterization of TOPs and their peptide substrates is required to understand their contributions to stress perception and defense signaling. Herein, label-free peptidomics via liquid chromatography-tandem mass spectrometry was used to differentially quantify 1111 peptides, originating from 369 proteins, between the Arabidopsis Col-0 wild type and top1top2 knock-out mutant. This revealed 350 peptides as significantly more abundant in the mutant, representing accumulation of these potential TOP substrates. Ten direct substrates were validated using in vitro enzyme assays with recombinant TOPs and synthetic candidate peptides. These TOP substrates are derived from proteins involved in photosynthesis, glycolysis, protein folding, biogenesis, and antioxidant defense, implicating TOP involvement in processes aside from defense signaling. Sequence motif analysis revealed TOP cleavage preference for non-polar residues in the positions surrounding the cleavage site. Identification of these substrates provides a framework for TOP signaling networks, through which the interplay between proteolytic pathways and defense signaling can be further characterized.
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Affiliation(s)
- Anthony A Iannetta
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Holden T Rogers
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Thualfeqar Al-Mohanna
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi, MS, USA
| | | | - Andrew J Wommack
- Department of Chemistry, High Point University, High Point, NC, USA
| | - Sorina C Popescu
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi, MS, USA
| | - Leslie M Hicks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Grahl MVC, Lopes FC, Martinelli AHS, Carlini CR, Fruttero LL. Structure-Function Insights of Jaburetox and Soyuretox: Novel Intrinsically Disordered Polypeptides Derived from Plant Ureases. Molecules 2020; 25:molecules25225338. [PMID: 33207637 PMCID: PMC7696265 DOI: 10.3390/molecules25225338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/05/2020] [Accepted: 11/06/2020] [Indexed: 12/24/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs) do not have a stable 3D structure but still have important biological activities. Jaburetox is a recombinant peptide derived from the jack bean (Canavalia ensiformis) urease and presents entomotoxic and antimicrobial actions. The structure of Jaburetox was elucidated using nuclear magnetic resonance which reveals it is an IDP with small amounts of secondary structure. Different approaches have demonstrated that Jaburetox acquires certain folding upon interaction with lipid membranes, a characteristic commonly found in other IDPs and usually important for their biological functions. Soyuretox, a recombinant peptide derived from the soybean (Glycine max) ubiquitous urease and homologous to Jaburetox, was also characterized for its biological activities and structural properties. Soyuretox is also an IDP, presenting more secondary structure in comparison with Jaburetox and similar entomotoxic and fungitoxic effects. Moreover, Soyuretox was found to be nontoxic to zebra fish, while Jaburetox was innocuous to mice and rats. This profile of toxicity affecting detrimental species without damaging mammals or the environment qualified them to be used in biotechnological applications. Both peptides were employed to develop transgenic crops and these plants were active against insects and nematodes, unveiling their immense potentiality for field applications.
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Affiliation(s)
- Matheus V. Coste Grahl
- Graduate Program in Medicine and Health Sciences, Brain Institute of Rio Grande do Sul (InsCer), Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre CEP 90610-000, Brazil;
| | - Fernanda Cortez Lopes
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, Building 43431, Porto Alegre CEP 91501-970, RS, Brazil;
| | - Anne H. Souza Martinelli
- Department of Biophysics & Deparment of Molecular Biology and Biotechnology-Biosciences Institute (IB), Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre 91501-970, RS, Brazil;
| | - Celia R. Carlini
- Graduate Program in Medicine and Health Sciences, Brain Institute of Rio Grande do Sul (InsCer), Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre CEP 90610-000, Brazil;
- Brain Institute and School of Medicine, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre 90610-000, RS, Brazil
- Correspondence: (C.R.C.); (L.L.F.); Tel.: +55-51-3320-3485 (C.R.C.); +54-351-535-3850 (L.L.F.)
| | - Leonardo L. Fruttero
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba CP 5000, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba CP 5000, Argentina
- Correspondence: (C.R.C.); (L.L.F.); Tel.: +55-51-3320-3485 (C.R.C.); +54-351-535-3850 (L.L.F.)
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Srivastava S, Dashora K, Ameta KL, Singh NP, El-Enshasy HA, Pagano MC, Hesham AEL, Sharma GD, Sharma M, Bhargava A. Cysteine-rich antimicrobial peptides from plants: The future of antimicrobial therapy. Phytother Res 2020; 35:256-277. [PMID: 32940412 DOI: 10.1002/ptr.6823] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/26/2020] [Accepted: 07/03/2020] [Indexed: 12/13/2022]
Abstract
There has been a spurt in the spread of microbial resistance to antibiotics due to indiscriminate use of antimicrobial agents in human medicine, agriculture, and animal husbandry. It has been realized that conventional antibiotic therapy would be less effective in the coming decades and more emphasis should be given for the development of novel antiinfective therapies. Cysteine rich peptides (CRPs) are broad-spectrum antimicrobial agents that modulate the innate immune system of different life forms such as bacteria, protozoans, fungi, plants, insects, and animals. These are also expressed in several plant tissues in response to invasion by pathogens, and play a crucial role in the regulation of plant growth and development. The present work explores the importance of CRPs as potent antimicrobial agents, which can supplement and/or replace the conventional antibiotics. Different plant parts of diverse plant species showed the presence of antimicrobial peptides (AMPs), which had significant structural and functional diversity. The plant-derived AMPs exhibited potent activity toward a range of plant and animal pathogens, protozoans, insects, and even against cancer cells. The cysteine-rich AMPs have opened new avenues for the use of plants as biofactories for the production of antimicrobials and can be considered as promising antimicrobial drugs in biotherapeutics.
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Affiliation(s)
- Shilpi Srivastava
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow Campus, Lucknow, India
| | - Kavya Dashora
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi, India
| | - Keshav Lalit Ameta
- Department of Chemistry, School of Liberal Arts and Sciences, Mody University of Science and Technology, Lakshmangarh, Rajasthan, India
| | | | - Hesham Ali El-Enshasy
- Institute of Bioproduct Development (IBD), School of Chemical and Energy Engineering, Universiti Teknologi Malaysia (UTM), Skudai, Johor Bahru, Malaysia.,City of Scientific Research and Technology Applications (SRTA), New Burg Al Arab, Alexandria, Egypt
| | | | - Abd El-Latif Hesham
- Genetics Department, Faculty of Agriculture, Beni-Suef University, Beni-Suef, Egypt
| | | | - Minaxi Sharma
- Department of Food Technology, Akal College of Agriculture, Eternal University, Baru Sahib, India
| | - Atul Bhargava
- Department of Botany, Mahatma Gandhi Central University, Motihari, India
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Tammineni R, Gulati P, Kumar S, Mohanty A. An overview of acyclotides: Past, present and future. PHYTOCHEMISTRY 2020; 170:112215. [PMID: 31812106 DOI: 10.1016/j.phytochem.2019.112215] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 06/10/2023]
Abstract
Acyclotides are plant-based, acyclic miniproteins with cystine knot motif formed by three conserved disulfide linkages and lack head to tail ligation. Acyclotides may not necessarily be less stable, even though they lack cyclic backbone, as the conserved cystine knot feature provides the required stability. Violacin A was the first acyclotide, isolated from Viola odorata in 2006. Until now, acyclotides have been reported from five dicot families (Violaceae, Rubiaceae, Cucurbitaceae, Solanaceae, Fabaceae) and one monocot family (Poaceae). In Poaceae, only acyclotides have been found whereas in dicot families both cyclotides and acyclotides have been isolated. In last 15 years, several acyclotides with antimicrobial, cytotoxic and hemolytic bioactivities have been discovered. Thus, although many naturally expressed acyclotides do exhibit bioactivities, the linearization of the cyclic peptides may result in loss of bioactivities. Although, bioactivities of acyclotides are comparable to their cyclic counterparts, the numbers of isolated acyclotides are still few. Further, those discovered, have the scope to be screened for agriculturally important activities (insecticidal, anti-helminthic, molluscicidal) and pharmaceutical properties (anticancer, anti-HIV, immuno-stimulant). The feasibility of application of acyclotides is because of their relatively less complex biological synthesis compared to cyclotides, as the cyclization step is not needed. This attribute facilitates the production of transgenic crops and/or its expression in heterologous organisms, lacking cyclization machinery. Keeping in view the bioactivities and the wide array of emerging potential applications of acyclotides, the present review discusses their distribution in plants, gene and protein structure, biosynthesis, bioactivities and mechanism of action. Further, their potential applications and future perspectives to exploit them in agriculture and pharmaceutical industries have been highlighted.
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Affiliation(s)
- Ramya Tammineni
- Bioinformatics Infrastructure Facility, Gargi College, University of Delhi, India
| | - Pooja Gulati
- Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana, India
| | - Sanjay Kumar
- Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana, India
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Abstract
This Review explores the class of plant-derived macrocyclic peptides called cyclotides. We include an account of their discovery, characterization, and distribution in the plant kingdom as well as a detailed analysis of their sequences and structures, biosynthesis and chemical synthesis, biological functions, and applications. These macrocyclic peptides are around 30 amino acids in size and are characterized by their head-to-tail cyclic backbone and cystine knot motif, which render them to be exceptionally stable, with resistance to thermal or enzymatic degradation. Routes to their chemical synthesis have been developed over the past two decades, and this capability has facilitated a wide range of mutagenesis and structure-activity relationship studies. In turn, these studies have both led to an increased understanding of their mechanisms of action as well as facilitated a range of applications in agriculture and medicine, as ecofriendly crop protection agents, and as drug leads or scaffolds for pharmaceutical design. Our overall objective in this Review is to provide readers with a comprehensive overview of cyclotides that we hope will stimulate further work on this fascinating family of peptides.
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Affiliation(s)
- Simon J de Veer
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - Meng-Wei Kan
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - David J Craik
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
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13
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Henriques ST, Peacock H, Benfield AH, Wang CK, Craik DJ. Is the Mirror Image a True Reflection? Intrinsic Membrane Chirality Modulates Peptide Binding. J Am Chem Soc 2019; 141:20460-20469. [PMID: 31765148 DOI: 10.1021/jacs.9b11194] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Peptides with pharmaceutical activities are attractive drug leads, and knowledge of their mode-of-action is essential for translation into the clinic. Comparison of native and enantiomeric peptides has long been used as a powerful approach to discriminate membrane- or receptor-mediated modes-of-action on the basis of the assumption that interactions with cell membranes are independent of peptide chirality. Here, we revisit this paradigm with the cyclotide kalata B1, a drug scaffold with intrinsic membrane-binding activity whose enantiomer is less potent than native peptide. To investigate this chirality dependence, we compared peptide-lipid binding using mirror image model membranes. We synthesized phospholipids with non-natural chirality and demonstrate that native kalata B1 binds with higher affinity to phospholipids with chirality found in eukaryotic membranes. This study shows for the first time that the chiral environment of lipid bilayers can modulate the function of membrane-active peptides and challenges the view that peptide-lipid interactions are achiral.
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Affiliation(s)
- Sónia Troeira Henriques
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia.,School of Biomedical Sciences, Faculty of Health, Institute of Health & Biomedical Innovation , Queensland University of Technology , Translational Research Institute , Brisbane , Queensland 4102 , Australia
| | - Hayden Peacock
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - Aurélie H Benfield
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia.,School of Biomedical Sciences, Faculty of Health, Institute of Health & Biomedical Innovation , Queensland University of Technology , Translational Research Institute , Brisbane , Queensland 4102 , Australia
| | - Conan K Wang
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - David J Craik
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
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14
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Huang YH, Du Q, Craik DJ. Cyclotides: Disulfide-rich peptide toxins in plants. Toxicon 2019; 172:33-44. [DOI: 10.1016/j.toxicon.2019.10.244] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 10/30/2019] [Accepted: 10/30/2019] [Indexed: 12/27/2022]
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15
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A suite of kinetically superior AEP ligases can cyclise an intrinsically disordered protein. Sci Rep 2019; 9:10820. [PMID: 31346249 PMCID: PMC6658665 DOI: 10.1038/s41598-019-47273-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 07/11/2019] [Indexed: 11/29/2022] Open
Abstract
Asparaginyl endopeptidases (AEPs) are a class of enzymes commonly associated with proteolysis in the maturation of seed storage proteins. However, a subset of AEPs work preferentially as peptide ligases, coupling release of a leaving group to formation of a new peptide bond. These “ligase-type” AEPs require only short recognition motifs to ligate a range of targets, making them useful tools in peptide and protein engineering for cyclisation of peptides or ligation of separate peptides into larger products. Here we report the recombinant expression, ligase activity and cyclisation kinetics of three new AEPs from the cyclotide producing plant Oldenlandia affinis with superior kinetics to the prototypical recombinant AEP ligase OaAEP1b. These AEPs work preferentially as ligases at both acidic and neutral pH and we term them “canonical AEP ligases” to distinguish them from other AEPs where activity preferences shift according to pH. We show that these ligases intrinsically favour ligation over hydrolysis, are highly efficient at cyclising two unrelated peptides and are compatible with organic co-solvents. Finally, we demonstrate the broad scope of recombinant AEPs in biotechnology by the backbone cyclisation of an intrinsically disordered protein, the 25 kDa malarial vaccine candidate Plasmodium falciparum merozoite surface protein 2 (MSP2).
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16
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Oguis GK, Gilding EK, Jackson MA, Craik DJ. Butterfly Pea ( Clitoria ternatea), a Cyclotide-Bearing Plant With Applications in Agriculture and Medicine. FRONTIERS IN PLANT SCIENCE 2019; 10:645. [PMID: 31191573 PMCID: PMC6546959 DOI: 10.3389/fpls.2019.00645] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 04/29/2019] [Indexed: 05/16/2023]
Abstract
The perennial leguminous herb Clitoria ternatea (butterfly pea) has attracted significant interest based on its agricultural and medical applications, which range from use as a fodder and nitrogen fixing crop, to applications in food coloring and cosmetics, traditional medicine and as a source of an eco-friendly insecticide. In this article we provide a broad multidisciplinary review that includes descriptions of the physical appearance, distribution, taxonomy, habitat, growth and propagation, phytochemical composition and applications of this plant. Notable amongst its repertoire of chemical components are anthocyanins which give C. ternatea flowers their characteristic blue color, and cyclotides, ultra-stable macrocyclic peptides that are present in all tissues of this plant. The latter are potent insecticidal molecules and are implicated as the bioactive agents in a plant extract used commercially as an insecticide. We include a description of the genetic origin of these peptides, which interestingly involve the co-option of an ancestral albumin gene to produce the cyclotide precursor protein. The biosynthesis step in which the cyclic peptide backbone is formed involves an asparaginyl endopeptidase, of which in C. ternatea is known as butelase-1. This enzyme is highly efficient in peptide ligation and has been the focus of many recent studies on peptide ligation and cyclization for biotechnological applications. The article concludes with some suggestions for future studies on this plant, including the need to explore possible synergies between the various peptidic and non-peptidic phytochemicals.
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Affiliation(s)
| | | | | | - David J. Craik
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
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17
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Niyomploy P, Chan LY, Harvey PJ, Poth AG, Colgrave ML, Craik DJ. Discovery and Characterization of Cyclotides from Rinorea Species. JOURNAL OF NATURAL PRODUCTS 2018; 81:2512-2520. [PMID: 30387611 DOI: 10.1021/acs.jnatprod.8b00572] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cyclotides are macrocyclic cystine-knotted peptides most commonly found in the Violaceae plant family. Although Rinorea is the second-largest genera within the Violaceae family, few studies have examined whether or not they contain cyclotides. To further our understanding of cyclotide diversity and evolution, we examined the cyclotide content of two Rinorea species found in Southeast Asia: R. virgata and R. bengalensis. Seven cyclotides were isolated from R. virgata (named Rivi1-7), and a known cyclotide (cT10) was found in R. bengalensis. Loops 2, 5, and 6 of Rivi1-4 contained sequences not previously seen in corresponding loops of known cyclotides, thereby expanding our understanding of the diversity of cyclotides. In addition, the sequence of loop 2 of Rivi3 and Rivi4 were identical to some related noncyclic "acyclotides" from the Poaceae plant family. As only acyclotides, but not cyclotides, have been reported in monocotyledons thus far, our findings support an evolutionary link between monocotyledon-derived ancestral cyclotide precursors and dicotyledon-derived cyclotides. Furthermore, Rivi2 and Rivi3 had comparable cytotoxic activities to the most cytotoxic cyclotide known to date: cycloviolacin O2 from Viola odorata; yet, unlike cycloviolacin O2, they did not show hemolytic activity. Therefore, these cyclotides represent novel scaffolds for use in future anticancer drug design.
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Affiliation(s)
- Ploypat Niyomploy
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
- Department of Chemistry, Faculty of Science , Chulalongkorn University , Bangkok 10330 , Thailand
| | - Lai Yue Chan
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - Peta J Harvey
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - Aaron G Poth
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - Michelle L Colgrave
- CSIRO Agriculture and Food , 306 Carmody Road , St. Lucia , Queensland 4067 , Australia
- School of Science , Edith Cowan University , 270 Joondalup Drive , Joondalup , WA 6027 , Australia
| | - David J Craik
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
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18
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Parsley NC, Kirkpatrick CL, Crittenden CM, Rad JG, Hoskin DW, Brodbelt JS, Hicks LM. PepSAVI-MS reveals anticancer and antifungal cycloviolacins in Viola odorata. PHYTOCHEMISTRY 2018; 152:61-70. [PMID: 29734037 PMCID: PMC6003877 DOI: 10.1016/j.phytochem.2018.04.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/12/2018] [Accepted: 04/24/2018] [Indexed: 05/07/2023]
Abstract
Widespread resistance to antimicrobial and cancer therapeutics is evolving in every country worldwide and has a direct impact on global health, agriculture and the economy. The specificity and selectivity of bioactive peptide natural products present a possible stopgap measure to address the ongoing deficit of new therapeutic compounds. PepSAVI-MS (Statistically-guided bioActive Peptides prioritized VIa Mass Spectrometry) is an adaptable method for the analysis of natural product libraries to rapidly identify bioactive peptides. This pipeline was validated via screening of the cyclotide-rich botanical species Viola odorata and identification of the known antimicrobial and anticancer cyclotide cycloviolacin O2. Herein we present and validate novel bioactivities of the anthelmintic V. odorata cyclotide, cycloviolacin O8 (cyO8), including micromolar anticancer activity against PC-3 prostate, MDA-MB-231 breast, and OVCAR-3 ovarian cancer cell lines and antifungal activity against the agricultural pathogen Fusarium graminearum. A reduction/alkylation strategy in tandem with PepSAVI-MS analysis also revealed several previously uncharacterized putatively bioactive cyclotides. Downstream implementation of ultraviolet photodissociation (UVPD) tandem mass spectrometry is demonstrated for cyO8 as a method to address traditionally difficult-to-sequence cyclotide species. This work emphasizes the therapeutic and agricultural potential of natural product bioactive peptides and the necessity of developing robust analytical tools to deconvolute nature's complexity.
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Affiliation(s)
- Nicole C Parsley
- Department of Chemistry, University of North Carolina at Chapel Hill, NC, USA
| | | | | | | | - David W Hoskin
- Department of Pathology, Dalhousie University, Nova Scotia, Canada; Department of Microbiology and Immunology, Dalhousie University, Nova Scotia, Canada; Department of Surgery, Dalhousie University, Nova Scotia, Canada
| | | | - Leslie M Hicks
- Department of Chemistry, University of North Carolina at Chapel Hill, NC, USA.
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19
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Craik DJ, Lee MH, Rehm FBH, Tombling B, Doffek B, Peacock H. Ribosomally-synthesised cyclic peptides from plants as drug leads and pharmaceutical scaffolds. Bioorg Med Chem 2017; 26:2727-2737. [PMID: 28818463 DOI: 10.1016/j.bmc.2017.08.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/12/2017] [Accepted: 08/06/2017] [Indexed: 12/28/2022]
Abstract
Owing to their exceptional stability and favourable pharmacokinetic properties, plant-derived cyclic peptides have recently attracted significant attention in the field of peptide-based drug design. This article describes the three major classes of ribosomally-synthesised plant peptides - the cyclotides, the PawS-derived peptides and the orbitides - and reviews their applications as leads or scaffolds in drug design. These ribosomally-produced peptides have a range of biological activities, including anti-HIV, cytotoxic and immunomodulatory activity. In addition, recent interest has focused on their use as scaffolds to stabilise bioactive peptide sequences, thereby enhancing their biopharmaceutical properties. There are now more than 30 published papers on such 'grafting' applications, most of which have been reported only in the last few years, and several such studies have reported in vivo activity of orally delivered cyclic peptides. In this article, we describe approaches to the synthesis of cyclic peptides and their pharmaceutically-grafted derivatives as well as outlining their biosynthetic routes. Finally, we describe possible bioproduction routes for pharmaceutically active cyclic peptides, involving plants and plant suspension cultures.
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Affiliation(s)
- David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.
| | - Meng-Han Lee
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Fabian B H Rehm
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Benjamin Tombling
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Benjamin Doffek
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Hayden Peacock
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
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20
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Cranfield CG, Henriques ST, Martinac B, Duckworth P, Craik DJ, Cornell B. Kalata B1 and Kalata B2 Have a Surfactant-Like Activity in Phosphatidylethanolomine-Containing Lipid Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:6630-6637. [PMID: 28605904 DOI: 10.1021/acs.langmuir.7b01642] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Cyclotides are cyclic disulfide-rich peptides that are chemically and thermally stable and possess pharmaceutical and insecticidal properties. The activities reported for cyclotides correlate with their ability to target phosphatidylethanolamine (PE)-phospholipids and disrupt cell membranes. However, the mechanism by which this disruption occurs remains unclear. In the current study we examine the effect of the prototypic cyclotides, kalata B1 (kB1) and kalata B2 (kB2), on tethered lipid bilayer membranes (tBLMs) using swept frequency electrical impedance spectroscopy. We confirmed that kB1 and kB2 bind to bilayers only if they contain PE-phospholipids. We hypothesize that the increase in membrane conduction and capacitance observed upon addition of kB1 or kB2 is unlikely to result from ion channel like pores but is consistent with the formation of lipidic toroidal pores. This hypothesis is supported by the concentration dependence of effects of kB1 and kB2 being suggestive of a critical micelle concentration event rather than a progressive increase in conduction arising from increased channel insertion. Additionally, conduction behavior is readily reversible when the peptide is rinsed from the bilayer. Our results support a mechanism by which kB1 and kB2 bind to and disrupt PE-containing membranes by decreasing the overall membrane critical packing parameter, as would a surfactant, which then opens or increases the size of existing membrane defects. The cyclotides need not participate directly in the conductive pore but might exert their effect indirectly through altering membrane packing constraints and inducing purely lipidic conductive pores.
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Affiliation(s)
- Charles G Cranfield
- School of Life Sciences, University of Technology Sydney , Ultimo, NSW 2007, Australia
| | - Sónia Troeira Henriques
- Institute for Molecular Bioscience, University of Queensland , Brisbane, Queensland 4072, Australia
| | - Boris Martinac
- Victor Chang Cardiac Research Institute , Darlinghurst, NSW 2010, Australia
- St Vincent's Clinical School, The University of New South Wales , Darlinghurst, NSW 2010, Australia
| | - Paul Duckworth
- SDx Tethered Membranes Pty Ltd , Unit 6 30-32 Barcoo Street, Roseville NSW 2069, Australia
| | - David J Craik
- Institute for Molecular Bioscience, University of Queensland , Brisbane, Queensland 4072, Australia
| | - Bruce Cornell
- School of Life Sciences, University of Technology Sydney , Ultimo, NSW 2007, Australia
- SDx Tethered Membranes Pty Ltd , Unit 6 30-32 Barcoo Street, Roseville NSW 2069, Australia
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21
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Grage SL, Sani MA, Cheneval O, Henriques ST, Schalck C, Heinzmann R, Mylne JS, Mykhailiuk PK, Afonin S, Komarov IV, Separovic F, Craik DJ, Ulrich AS. Orientation and Location of the Cyclotide Kalata B1 in Lipid Bilayers Revealed by Solid-State NMR. Biophys J 2017; 112:630-642. [PMID: 28256223 PMCID: PMC5340158 DOI: 10.1016/j.bpj.2016.12.040] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 12/23/2016] [Accepted: 12/29/2016] [Indexed: 02/04/2023] Open
Abstract
Cyclotides are ultra-stable cyclic disulfide-rich peptides from plants. Their biophysical effects and medically interesting activities are related to their membrane-binding properties, with particularly high affinity for phosphatidylethanolamine lipids. In this study we were interested in understanding the molecular details of cyclotide-membrane interactions, specifically with regard to the spatial orientation of the cyclotide kalata B1 from Oldenlandia affinis when embedded in a lipid bilayer. Our experimental approach was based on the use of solid-state 19F-NMR of oriented bilayers in conjunction with the conformationally restricted amino acid L-3-(trifluoromethyl)bicyclopent-[1.1.1]-1-ylglycine as an orientation-sensitive 19F-NMR probe. Its rigid connection to the kalata B1 backbone scaffold, together with the well-defined structure of the cyclotide, allowed us to calculate the protein alignment in the membrane directly from the orientation-sensitive 19F-NMR signal. The hydrophobic and polar residues on the surface of kalata B1 form well-separated patches, endowing this cyclotide with a pronounced amphipathicity. The peptide orientation, as determined by NMR, showed that this amphipathic structure matches the polar/apolar interface of the lipid bilayer very well. A location in the amphiphilic headgroup region of the bilayer was supported by 15N-NMR of uniformly labeled protein, and confirmed using solid-state 31P- and 2H-NMR. 31P-NMR relaxation data indicated a change in lipid headgroup dynamics induced by kalata B1. Changes in the 2H-NMR order parameter profile of the acyl chains suggest membrane thinning, as typically observed for amphiphilic peptides embedded near the polar/apolar bilayer interface. Furthermore, from the 19F-NMR analysis two important charged residues, E7 and R28, were found to be positioned equatorially. The observed location thus would be favorable for the postulated binding of E7 to phosphatidylethanolamine lipid headgroups. Furthermore, it may be speculated that this pair of side chains could promote oligomerization of kalata B1 through electrostatic intermolecular contacts via their complementary charges.
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Affiliation(s)
- Stephan L Grage
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Olivier Cheneval
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Sónia Troeira Henriques
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Constantin Schalck
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Ralf Heinzmann
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Joshua S Mylne
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Pavel K Mykhailiuk
- Chemistry Department, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine; Enamine Ltd., Kyiv, Ukraine
| | - Sergii Afonin
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Igor V Komarov
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Anne S Ulrich
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology, Karlsruhe, Germany; Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany.
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22
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Daly NL, Gunasekera S, Clark RJ, Lin F, Wade JD, Anderson MA, Craik DJ. The N-terminal pro-domain of the kalata B1 cyclotide precursor is intrinsically unstructured. Biopolymers 2017; 106:825-833. [PMID: 27564841 DOI: 10.1002/bip.22977] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 08/23/2016] [Accepted: 08/25/2016] [Indexed: 11/09/2022]
Abstract
Cyclotides are plant-derived, gene-encoded, circular peptides with a range of host-defense functions, including insecticidal activity. They also have potential as pharmaceutical scaffolds and understanding their biosynthesis is important to facilitate their large-scale production. Insights into the biosynthesis of cyclotides are emerging but there are still open questions, particularly regarding the influence of the structure of the precursor proteins on processing/biosynthetic pathways. The precursor protein of kalata B1, encoded by the plant Oldenlandia affinis, contains N- and C-terminal propeptides that flank the mature cyclotide domain. The C-terminal region (ctr) is important for the cyclization process, whereas the N-terminal repeat (ntr) has been implicated in vacuolar targeting. In this study we examined the structure and folding of various truncated constructs of the ntr coupled to the mature domain of kalata B1. Despite the ntr having a well-defined helical structure in isolation, once coupled to the natively folded mature domain there is no evidence of an ordered structure. Surprisingly, the ntr appears to be highly disordered and induces self-association of the precursor. This self-association might be associated with the role of the ntr as a vacuolar-targeting signal, as previously shown for unrelated storage proteins.
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Affiliation(s)
- Norelle L Daly
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Sunithi Gunasekera
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Richard J Clark
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Feng Lin
- Howard Florey Institute, University of Melbourne, Victoria, 3010, Australia
| | - John D Wade
- Howard Florey Institute, University of Melbourne, Victoria, 3010, Australia
| | - Marilyn A Anderson
- Department of Biochemistry, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
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23
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Abdul Ghani H, Henriques ST, Huang YH, Swedberg JE, Schroeder CI, Craik DJ. Structural and functional characterization of chimeric cyclotides from the Möbius and trypsin inhibitor subfamilies. Biopolymers 2017; 108. [DOI: 10.1002/bip.22927] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/22/2016] [Accepted: 07/27/2016] [Indexed: 01/22/2023]
Affiliation(s)
- Hafiza Abdul Ghani
- Institute for Molecular Bioscience, The University of Queensland; Brisbane Queensland 4072 Australia
| | - Sónia Troeira Henriques
- Institute for Molecular Bioscience, The University of Queensland; Brisbane Queensland 4072 Australia
| | - Yen-Hua Huang
- Institute for Molecular Bioscience, The University of Queensland; Brisbane Queensland 4072 Australia
| | - Joakim E. Swedberg
- Institute for Molecular Bioscience, The University of Queensland; Brisbane Queensland 4072 Australia
| | - Christina I. Schroeder
- Institute for Molecular Bioscience, The University of Queensland; Brisbane Queensland 4072 Australia
| | - David J. Craik
- Institute for Molecular Bioscience, The University of Queensland; Brisbane Queensland 4072 Australia
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24
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Troeira Henriques S, Craik DJ. Cyclotide Structure and Function: The Role of Membrane Binding and Permeation. Biochemistry 2017; 56:669-682. [DOI: 10.1021/acs.biochem.6b01212] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sónia Troeira Henriques
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, 4072 QLD, Australia
| | - David J. Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, 4072 QLD, Australia
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25
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Koehbach J, Clark RJ. Unveiling the diversity of cyclotides by combining peptidome and transcriptome analysis. Biopolymers 2016; 106:774-783. [DOI: 10.1002/bip.22858] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/05/2016] [Accepted: 04/11/2016] [Indexed: 01/11/2023]
Affiliation(s)
- Johannes Koehbach
- School of Biomedical Sciences; The University of Queensland; 4072 St. Lucia QLD Australia
| | - Richard J. Clark
- School of Biomedical Sciences; The University of Queensland; 4072 St. Lucia QLD Australia
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26
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Niyomploy P, Chan LY, Poth AG, Colgrave ML, Sangvanich P, Craik DJ. Discovery, isolation, and structural characterization of cyclotides from
Viola sumatrana
Miq. Pept Sci (Hoboken) 2016; 106:796-805. [DOI: 10.1002/bip.22914] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/21/2016] [Accepted: 06/29/2016] [Indexed: 01/18/2023]
Affiliation(s)
- Ploypat Niyomploy
- Institute for Molecular Bioscience, The University of QueenslandBrisbane QLD4072 Australia
- Department of Chemistry, Faculty of ScienceChulalongkorn UniversityBangkok10330 Thailand
| | - Lai Yue Chan
- Institute for Molecular Bioscience, The University of QueenslandBrisbane QLD4072 Australia
| | - Aaron G. Poth
- Institute for Molecular Bioscience, The University of QueenslandBrisbane QLD4072 Australia
| | | | - Polkit Sangvanich
- Department of Chemistry, Faculty of ScienceChulalongkorn UniversityBangkok10330 Thailand
| | - David J. Craik
- Institute for Molecular Bioscience, The University of QueenslandBrisbane QLD4072 Australia
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27
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28
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Weidmann J, Craik DJ. Discovery, structure, function, and applications of cyclotides: circular proteins from plants. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:4801-12. [PMID: 27222514 DOI: 10.1093/jxb/erw210] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Cyclotides are plant-derived cyclic peptides that have a head-to-tail cyclic backbone and three conserved disulphide bonds that form a cyclic cystine knot motif. They occur in plants from the Violaceae, Rubiaceae, Cucurbitaceae, Fabaceae, and Solanaceae families, typically with 10-100 cyclotides in a given plant species, in a wide range of tissues, including flowers, leaves, stems, and roots. Some cyclotides are expressed in large amounts (up to 1g kg(-1) wet plant weight) and their natural function appears to be to protect plants from pests or pathogens. This article provides a brief overview of their discovery, distribution in plants, and applications. In particular, their exceptional stability has led to their use as peptide-based scaffolds in drug design applications. They also have potential as natural 'ecofriendly' insecticides, and as protein engineering frameworks.
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Affiliation(s)
- Joachim Weidmann
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
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29
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Nguyen KNT, Nguyen GKT, Nguyen PQT, Ang KH, Dedon PC, Tam JP. Immunostimulating and Gram-negative-specific antibacterial cyclotides from the butterfly pea (Clitoria ternatea). FEBS J 2016; 283:2067-90. [DOI: 10.1111/febs.13720] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 02/05/2016] [Accepted: 03/22/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Kim Ngan T. Nguyen
- School of Biological Sciences; Nanyang Technological University; Singapore City Singapore
| | - Giang Kien Truc Nguyen
- School of Biological Sciences; Nanyang Technological University; Singapore City Singapore
| | | | - Koon Hwee Ang
- School of Biological Sciences; Nanyang Technological University; Singapore City Singapore
| | - Peter C. Dedon
- Department of Biological Engineering; Massachusetts Institute of Technology; Cambridge MA USA
| | - James P. Tam
- School of Biological Sciences; Nanyang Technological University; Singapore City Singapore
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30
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Serra A, Hemu X, Nguyen GKT, Nguyen NTK, Sze SK, Tam JP. A high-throughput peptidomic strategy to decipher the molecular diversity of cyclic cysteine-rich peptides. Sci Rep 2016; 6:23005. [PMID: 26965458 PMCID: PMC4786859 DOI: 10.1038/srep23005] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 02/25/2016] [Indexed: 01/03/2023] Open
Abstract
Cyclotides are plant cyclic cysteine-rich peptides (CRPs). The cyclic nature is reported to be gene-determined with a precursor containing a cyclization-competent domain which contains an essential C-terminal Asn/Asp (Asx) processing signal recognized by a cyclase. Linear forms of cyclotides are rare and are likely uncyclizable because they lack this essential C-terminal Asx signal (uncyclotide). Here we show that in the cyclotide-producing plant Clitoria ternatea, both cyclic and acyclic products, collectively named cliotides, can be bioprocessed from the same cyclization-competent precursor. Using an improved peptidomic strategy coupled with the novel Asx-specific endopeptidase butelase 2 to linearize cliotides at a biosynthetic ligation site for transcriptomic analysis, we characterized 272 cliotides derived from 38 genes. Several types of post-translational modifications of the processed cyclotides were observed, including deamidation, oxidation, hydroxylation, dehydration, glycosylation, methylation, and truncation. Taken together, our results suggest that cyclotide biosynthesis involves 'fuzzy' processing of precursors into both cyclic and linear forms as well as post-translational modifications to achieve molecular diversity, which is a commonly found trait of natural product biosynthesis.
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Affiliation(s)
- Aida Serra
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Xinya Hemu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Giang K. T. Nguyen
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Ngan T. K. Nguyen
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Siu Kwan Sze
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - James P. Tam
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
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31
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Ravipati AS, Henriques ST, Poth AG, Kaas Q, Wang CK, Colgrave ML, Craik DJ. Lysine-rich Cyclotides: A New Subclass of Circular Knotted Proteins from Violaceae. ACS Chem Biol 2015; 10:2491-500. [PMID: 26322745 DOI: 10.1021/acschembio.5b00454] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyclotides are macrocyclic proteins produced by plants for host defense. Although they occur sparsely in other plant families, cyclotides have been detected in every Violaceae plant species so far screened. Many of the Violaceae species examined until now have been from closely related geographical regions or habitats. To test the hypothesis that cyclotides are ubiquitous in this family, two geographically isolated (and critically endangered) species of Australasian Violaceae, namely Melicytus chathamicus and M. latifolius, were examined. Surprisingly, we discovered a suite of cyclotides possessing novel sequence features, including a lysine-rich nature, distinguishing them from "conventional" cyclotides and suggesting that they might have different physiological activities in plants to those reported to date. The newly discovered cyclotides were found to bind to lipid membranes and were cytotoxic against cancer cell lines but had low toxicity against red blood cells, which is advantageous for potential therapeutic applications. This suite of novel Lys-rich cyclotides emphasizes the broad diversity of cyclotides in Violaceae species.
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Affiliation(s)
- Anjaneya S. Ravipati
- Institute
for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Sónia Troeira Henriques
- Institute
for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Aaron G. Poth
- Institute
for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Quentin Kaas
- Institute
for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Conan K. Wang
- Institute
for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Michelle L. Colgrave
- Commonwealth Scientific and Industrial Research Organization, Agriculture Flagship, St. Lucia, Queensland 4067, Australia
| | - David J. Craik
- Institute
for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
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Hellinger R, Koehbach J, Soltis DE, Carpenter EJ, Wong GKS, Gruber CW. Peptidomics of Circular Cysteine-Rich Plant Peptides: Analysis of the Diversity of Cyclotides from Viola tricolor by Transcriptome and Proteome Mining. J Proteome Res 2015; 14:4851-62. [PMID: 26399495 PMCID: PMC4642221 DOI: 10.1021/acs.jproteome.5b00681] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
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Cyclotides are plant-derived mini proteins. They are genetically
encoded as precursor proteins that become post-translationally modified
to yield circular cystine-knotted molecules. Because of this structural
topology cyclotides resist enzymatic degradation in biological fluids,
and hence they are considered as promising lead molecules for pharmaceutical
applications. Despite ongoing efforts to discover novel cyclotides
and analyze their biodiversity, it is not clear how many individual
peptides a single plant specimen can express. Therefore, we investigated
the transcriptome and cyclotide peptidome of Viola tricolor. Transcriptome mining enabled the characterization of cyclotide
precursor architecture and processing sites important for biosynthesis
of mature peptides. The cyclotide peptidome was explored by mass spectrometry
and bottom-up proteomics using the extracted peptide sequences as
queries for database searching. In total 164 cyclotides were discovered
by nucleic acid and peptide analysis in V. tricolor. Therefore, violaceous plants at a global scale may be the source
to as many as 150 000 individual cyclotides. Encompassing the
diversity of V. tricolor as a combinatorial library
of bioactive peptides, this commercially available medicinal herb
may be a suitable starting point for future bioactivity-guided screening
studies.
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Affiliation(s)
- Roland Hellinger
- Center for Physiology and Pharmacology, Medical University of Vienna , Schwarzspanierstrasse 17, 1090 Vienna, Austria
| | - Johannes Koehbach
- Center for Physiology and Pharmacology, Medical University of Vienna , Schwarzspanierstrasse 17, 1090 Vienna, Austria.,School of Biomedical Sciences, The University of Queensland , St. Lucia, Queensland 4072, Australia
| | - Douglas E Soltis
- Florida Museum of Natural History, University of Florida , Gainesville, Florida 32611, United States
| | - Eric J Carpenter
- Department of Biological Sciences, University of Alberta , Edmonton, Alberta T6G 2E9, Canada
| | - Gane Ka-Shu Wong
- Department of Biological Sciences, University of Alberta , Edmonton, Alberta T6G 2E9, Canada.,Department of Medicine, University of Alberta , Edmonton, Alberta T6G 2E1, Canada.,BGI-Shenzhen, Beishan Industrial Zone, Yantian District, Shenzhen 518083, China
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna , Schwarzspanierstrasse 17, 1090 Vienna, Austria.,School of Biomedical Sciences, The University of Queensland , St. Lucia, Queensland 4072, Australia
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33
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Henriques S, Huang YH, Chaousis S, Sani MA, Poth A, Separovic F, Craik D. The Prototypic Cyclotide Kalata B1 Has a Unique Mechanism of Entering Cells. ACTA ACUST UNITED AC 2015; 22:1087-97. [DOI: 10.1016/j.chembiol.2015.07.012] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 06/20/2015] [Accepted: 07/08/2015] [Indexed: 12/29/2022]
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Zhang J, Li J, Huang Z, Yang B, Zhang X, Li D, Craik DJ, Baker AJM, Shu W, Liao B. Transcriptomic screening for cyclotides and other cysteine-rich proteins in the metallophyte Viola baoshanensis. JOURNAL OF PLANT PHYSIOLOGY 2015; 178:17-26. [PMID: 25756919 DOI: 10.1016/j.jplph.2015.01.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 01/01/2015] [Accepted: 01/28/2015] [Indexed: 06/04/2023]
Abstract
Cysteine (Cys)-rich proteins (CRPs) are frequently associated with plant defense and stress resistance. Viola baoshanensis is a cadmium (Cd) hyper-accumulating plant whose CRPs-based defense systems are so far poorly understood. Next generation sequencing (NGS) techniques and a specialist searching tool, CrpExcel, were employed for identifying CRPs in V. baoshanensis. The transcriptome sequences of V. baoshanensis were assembled primarily from 454FLX/Hiseq2000 reads of plant cDNA sequencing libraries. CrpExcel was then used to search the ORFs and 9687 CRPs were identified, and included zinc finger (ZF) proteins, lipid transfer proteins, thaumatins and cyclotide precursors. Real-time PCR results showed that all CRP genes tested are constitutively expressed, but the genes of defensive peptides showed greater up-regulated expression than those of ZF-proteins in Cd- and/or wounding (Wd) treatments of V. baoshanensis seedlings. The NGS-derived sequences of cyclotide precursor genes were verified by RT-PCR and ABI3730 sequencing studies, and 32 novel cyclotides were identified in V. baoshanensis. In general, the metal-binding sites of ZF-containing CRPs also represented the potential vulnerable targets of toxic metals. This study provides broad insights into CRPs-based defense systems and stress-vulnerable targets in V. baoshanensis. It now brings the number of cyclotide sequences in V. baoshanensis to 53 and based on projections from this work, the number of cyclotides in the Violaceae is now conservatively estimated to be >30000.
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Affiliation(s)
- Jun Zhang
- Guangdong Pharmaceutical University, School of Biosciences and Biopharmaceutics, Guangdong Province Key Laboratory for Biotechnology Drug Candidates, Guangzhou 510006, China; Sun Yat-sen University, School of Life Sciences, State Key Laboratory of Biocontrol, Guangzhou 510006, China.
| | - Jintian Li
- Sun Yat-sen University, School of Life Sciences, State Key Laboratory of Biocontrol, Guangzhou 510006, China.
| | - Zebo Huang
- Guangdong Pharmaceutical University, School of Biosciences and Biopharmaceutics, Guangdong Province Key Laboratory for Biotechnology Drug Candidates, Guangzhou 510006, China.
| | - Bing Yang
- Sun Yat-sen University, School of Life Sciences, State Key Laboratory of Biocontrol, Guangzhou 510006, China.
| | - Xiaojie Zhang
- Guangdong Pharmaceutical University, School of Biosciences and Biopharmaceutics, Guangdong Province Key Laboratory for Biotechnology Drug Candidates, Guangzhou 510006, China.
| | - Dehua Li
- Guangdong Pharmaceutical University, School of Biosciences and Biopharmaceutics, Guangdong Province Key Laboratory for Biotechnology Drug Candidates, Guangzhou 510006, China.
| | - David J Craik
- The University of Queensland, Institute for Molecular Bioscience, Brisbane 4072, QLD, Australia.
| | - Alan J M Baker
- The University of Melbourne, School of Botany, Parkville 3010, VIC, Australia.
| | - Wensheng Shu
- Sun Yat-sen University, School of Life Sciences, State Key Laboratory of Biocontrol, Guangzhou 510006, China.
| | - Bin Liao
- Sun Yat-sen University, School of Life Sciences, State Key Laboratory of Biocontrol, Guangzhou 510006, China.
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35
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Burman R, Yeshak MY, Larsson S, Craik DJ, Rosengren KJ, Göransson U. Distribution of circular proteins in plants: large-scale mapping of cyclotides in the Violaceae. FRONTIERS IN PLANT SCIENCE 2015; 6:855. [PMID: 26579135 PMCID: PMC4621522 DOI: 10.3389/fpls.2015.00855] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/28/2015] [Indexed: 05/02/2023]
Abstract
During the last decade there has been increasing interest in small circular proteins found in plants of the violet family (Violaceae). These so-called cyclotides consist of a circular chain of approximately 30 amino acids, including six cysteines forming three disulfide bonds, arranged in a cyclic cystine knot (CCK) motif. In this study we map the occurrence and distribution of cyclotides throughout the Violaceae. Plant material was obtained from herbarium sheets containing samples up to 200 years of age. Even the oldest specimens contained cyclotides in the preserved leaves, with no degradation products observable, confirming their place as one of the most stable proteins in nature. Over 200 samples covering 17 of the 23-31 genera in Violaceae were analyzed, and cyclotides were positively identified in 150 species. Each species contained a unique set of between one and 25 cyclotides, with many exclusive to individual plant species. We estimate the number of different cyclotides in the Violaceae to be 5000-25,000, and propose that cyclotides are ubiquitous among all Violaceae species. Twelve new cyclotides from six phylogenetically dispersed genera were sequenced. Furthermore, the first glycosylated derivatives of cyclotides were identified and characterized, further increasing the diversity and complexity of this unique protein family.
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Affiliation(s)
- Robert Burman
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala UniversityUppsala, Sweden
| | - Mariamawit Y. Yeshak
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala UniversityUppsala, Sweden
- Department of Pharmacognosy, School of Pharmacy, Addis Ababa UniversityAddis Ababa, Ethiopia
| | - Sonny Larsson
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala UniversityUppsala, Sweden
| | - David J. Craik
- Craik Lab, Chemistry and Structural Biology Division, Institute for Molecular Bioscience, The University of QueenslandBrisbane, QLD, Australia
| | - K. Johan Rosengren
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala UniversityUppsala, Sweden
- Laboratory for Peptide Structural Biology, School of Biomedical Sciences, The University of QueenslandBrisbane, QLD, Australia
| | - Ulf Göransson
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala UniversityUppsala, Sweden
- *Correspondence: Ulf Göransson
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36
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Structural parameters modulating the cellular uptake of disulfide-rich cyclic cell-penetrating peptides: MCoTI-II and SFTI-1. Eur J Med Chem 2014; 88:10-8. [DOI: 10.1016/j.ejmech.2014.06.047] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 06/17/2014] [Accepted: 06/18/2014] [Indexed: 01/13/2023]
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37
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Troeira Henriques S, Huang YH, Chaousis S, Wang CK, Craik DJ. Anticancer and toxic properties of cyclotides are dependent on phosphatidylethanolamine phospholipid targeting. Chembiochem 2014; 15:1956-65. [PMID: 25099014 DOI: 10.1002/cbic.201402144] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Indexed: 11/11/2022]
Abstract
Cyclotides, ultrastable disulfide-rich cyclic peptides, can be engineered to bind and inhibit specific cancer targets. In addition, some cyclotides are toxic to cancer cells, though not much is known about their mechanisms of action. Here we delineated the potential mode of action of cyclotides towards cancer cells. A novel set of analogues of kalata B1 (the prototypic cyclotide) and kalata B2 and cycloviolacin O2 were examined for their membrane-binding affinity and selectivity towards cancer cells. By using solution-state NMR, surface plasmon resonance, flow cytometry and bioassays we show that cyclotides are toxic against cancer and non-cancerous cells and their toxicity correlates with their ability to target and disrupt lipid bilayers that contain phosphatidylethanolamine phospholipids. Our results suggest that the potential of cyclotides as anticancer therapeutics might best be realised by combining their amenability to epitope engineering with their ability to bind cancer cell membranes.
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Affiliation(s)
- Sónia Troeira Henriques
- The University of Queensland, Institute for Molecular Bioscience, Carmody Road, St. Lucia, Brisbane, QLD 4072 (Australia).
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38
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de Souza Cândido E, e Silva Cardoso MH, Sousa DA, Viana JC, de Oliveira-Júnior NG, Miranda V, Franco OL. The use of versatile plant antimicrobial peptides in agribusiness and human health. Peptides 2014; 55:65-78. [PMID: 24548568 DOI: 10.1016/j.peptides.2014.02.003] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 02/05/2014] [Accepted: 02/07/2014] [Indexed: 12/11/2022]
Abstract
Plant immune responses involve a wide diversity of physiological reactions that are induced by the recognition of pathogens, such as hypersensitive responses, cell wall modifications, and the synthesis of antimicrobial molecules including antimicrobial peptides (AMPs). These proteinaceous molecules have been widely studied, presenting peculiar characteristics such as conserved domains and a conserved disulfide bond pattern. Currently, many AMP classes with diverse modes of action are known, having been isolated from a large number of organisms. Plant AMPs comprise an interesting source of studies nowadays, and among these there are reports of different classes, including defensins, albumins, cyclotides, snakins and several others. These peptides have been widely used in works that pursue human disease control, including nosocomial infections, as well as for agricultural purposes. In this context, this review will focus on the relevance of the structural-function relations of AMPs derived from plants and their proper use in applications for human health and agribusiness.
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Affiliation(s)
- Elizabete de Souza Cândido
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil; Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil
| | - Marlon Henrique e Silva Cardoso
- Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil
| | - Daniel Amaro Sousa
- Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil; Programa de Pós-Graduação em Patologia Molecular, Universidade de Brasília, Brasília, DF, Brazil
| | - Juliane Cançado Viana
- Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil; Programa de Pós-Graduação em Patologia Molecular, Universidade de Brasília, Brasília, DF, Brazil
| | - Nelson Gomes de Oliveira-Júnior
- Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil; Programa de Pós-Graduação em Biologia Animal, Universidade de Brasília, Brasília, DF, Brazil
| | - Vívian Miranda
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil; Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil
| | - Octávio Luiz Franco
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil; Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil; Programa de Pós-Graduação em Patologia Molecular, Universidade de Brasília, Brasília, DF, Brazil.
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39
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Craik DJ, Malik U. Cyclotide biosynthesis. Curr Opin Chem Biol 2013; 17:546-54. [PMID: 23809361 DOI: 10.1016/j.cbpa.2013.05.033] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 05/28/2013] [Indexed: 10/26/2022]
Abstract
Cyclotides are bioactive macrocyclic peptides from plants that are characterized by their exceptional stability and potential applications as protein engineering or drug design frameworks. Their stability arises from their unique cyclic cystine knot structure, which combines a head-to-tail cyclic peptide backbone with three conserved disulfide bonds having a knotted topology. Cyclotides are ribosomally synthesized by plants and expressed in a wide range of tissues, including leaves, flowers, stems and roots. Here we describe recent studies that have examined the biosynthesis of cyclotides and in particular the mechanism associated with post-translational backbone cyclization.
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Affiliation(s)
- David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
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40
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Yeshak MY, Göransson U, Burman R, Hellman B. Genotoxicity and cellular uptake of cyclotides: Evidence for multiple modes of action. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2012; 747:176-81. [DOI: 10.1016/j.mrgentox.2012.05.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 03/20/2012] [Accepted: 05/02/2012] [Indexed: 10/28/2022]
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41
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Henriques ST, Huang YH, Castanho MARB, Bagatolli LA, Sonza S, Tachedjian G, Daly NL, Craik DJ. Phosphatidylethanolamine binding is a conserved feature of cyclotide-membrane interactions. J Biol Chem 2012; 287:33629-43. [PMID: 22854971 DOI: 10.1074/jbc.m112.372011] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Cyclotides are bioactive cyclic peptides isolated from plants that are characterized by a topologically complex structure and exceptional resistance to enzymatic or thermal degradation. With their sequence diversity, ultra-stable core structural motif, and range of bioactivities, cyclotides are regarded as a combinatorial peptide template with potential applications in drug design. The mode of action of cyclotides remains elusive, but all reported biological activities are consistent with a mechanism involving membrane interactions. In this study, a diverse set of cyclotides from the two major subfamilies, Möbius and bracelet, and an all-d mirror image form, were examined to determine their mode of action. Their lipid selectivity and membrane affinity were determined, as were their toxicities against a range of targets (red blood cells, bacteria, and HIV particles). Although they had different membrane-binding affinities, all of the tested cyclotides targeted membranes through binding to phospholipids containing phosphatidylethanolamine headgroups. Furthermore, the biological potency of the tested cyclotides broadly correlated with their ability to target and disrupt cell membranes. The finding that a broad range of cyclotides target a specific lipid suggests their categorization as a new lipid-binding protein family. Knowledge of their membrane specificity has the potential to assist in the design of novel drugs based on the cyclotide framework, perhaps allowing the targeting of peptide drugs to specific cell types.
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Affiliation(s)
- Sónia Troeira Henriques
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, 4072 Queensland, Australia
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42
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Henriques ST, Craik DJ. Importance of the cell membrane on the mechanism of action of cyclotides. ACS Chem Biol 2012; 7:626-36. [PMID: 22260456 DOI: 10.1021/cb200395f] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Their distinctive structures, diverse range of bioactivities, and potential for pharmaceutical or agricultural applications make cyclotides an intriguing family of cyclic peptides. Together with the physiological role in plant host defense, cyclotides possess antimicrobial, anticancer, and anti-HIV activities. In all of the reported activities, cell membranes seem to be the primary target for cyclotide binding. This article examines recent literature on cyclotide-membrane studies and highlights the hypothesis that the activity of cyclotides is dependent on their affinity for lipid bilayers and enhanced by the presence of specific lipids, i.e., phospholipids containing phosphatidylethanolamine headgroups. There is growing evidence that the lipid composition of target cell membranes dictates the amount of cyclotides bound to the cell and the extent of their activity. After membrane targeting and insertion in the bilayer core, cyclotides induce disruption of membranes by a pore formation mechanism. This proposed mechanism of action is supported by biophysical studies with model membranes and by studies on natural biological membranes of known lipid compositions.
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Affiliation(s)
- Sónia Troeira Henriques
- Institute
for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
- Institute of Molecular Medicine,
Medical School, University of Lisbon, 1649-028
Lisbon, Portugal
| | - David J. Craik
- Institute
for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
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43
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Nguyen GKT, Lim WH, Nguyen PQT, Tam JP. Novel cyclotides and uncyclotides with highly shortened precursors from Chassalia chartacea and effects of methionine oxidation on bioactivities. J Biol Chem 2012; 287:17598-17607. [PMID: 22467870 DOI: 10.1074/jbc.m111.338970] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclotides are a new class of plant biologics that display a diverse range of bioactivities with therapeutic potentials. They possess an unusual end-to-end cyclic backbone combined with a cystine knot arrangement, making them exceptionally stable to heat, chemical and enzymatic degradation. Currently, >200 cyclotides have been discovered but only three naturally occurring linear variants (also known as uncyclotides) have been isolated. In this study, we report the discovery of 18 novel peptides, chassatides C1 to C18, composed of 14 new cyclotides and four uncyclotides from Chassalia chartacea (Rubiaceae family). Thus far, this is the largest number of uncyclotides being reported in a single species. Activity testing showed that the uncyclotides not only retain the effectiveness but also are the most potent chassatides in the assays for antimicrobial, cytotoxic, and hemolytic activities. Genetic characterization of novel chassatides revealed that they have the shortest precursors of all known cyclotides hitherto isolated, which represents a new class of cyclotide precursors. This is the first report of cyclotide genes in a second genus, the Chassalia, other than the Hedyotis (Oldenlandia) of the Rubiaceae family. In addition, we also report the characterization of two Met-oxidized derivatives of chassatides C2 and C11. The oxidation of Met residue causes loss of bioactivities, strengthening the importance of the hydrophobic patch for membrane interaction.
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Affiliation(s)
| | - Wei Han Lim
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | | | - James P Tam
- School of Biological Sciences, Nanyang Technological University, Singapore 637551.
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44
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Gründemann C, Koehbach J, Huber R, Gruber CW. Do plant cyclotides have potential as immunosuppressant peptides? JOURNAL OF NATURAL PRODUCTS 2012; 75:167-74. [PMID: 22272797 PMCID: PMC3399773 DOI: 10.1021/np200722w] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Cyclotides are an abundant and diverse group of ribosomally synthesized plant peptides containing a cyclic cystine-knotted structure that confers them with remarkable stability. They are explored for their distribution in plants, although little is known about the individual peptide content of a single species. Therefore, we chemically analyzed the crude extract of the coffee-family plant Oldenlandia affinis using a rapid peptidomics workflow utilizing nano-LC-MS, peptide reconstruct with database identification, and MS/MS automated sequence analysis to determine its cyclotide content. Biologically, cyclotides are mainly explored for applications in agriculture and drug design; here we report their growth-inhibiting effects on primary cells of the human immune system using biological and immunological end points in cell-based test systems. LC-MS quantification of the active O. affinis plant extract triggered the characterization of the antiproliferative activity of kalata B1, one of the most abundant cyclotides in this extract, on primary activated human lymphocytes. The effect has a defined concentration range and was not due to cytotoxicity, thus opening a new avenue to utilize native and synthetically optimized plant cyclotides for applications in immune-related disorders and as immunosuppressant peptides.
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Affiliation(s)
- Carsten Gründemann
- Center for Complementary Medicine, Department of Environmental Health Sciences, University Medical Center Freiburg, Breisacher Straße 115B, D-79111 Freiburg, Germany
| | - Johannes Koehbach
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstraße 17, A-1090 Vienna, Austria
| | - Roman Huber
- Center for Complementary Medicine, Department of Environmental Health Sciences, University Medical Center Freiburg, Breisacher Straße 115B, D-79111 Freiburg, Germany
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstraße 17, A-1090 Vienna, Austria
- Corresponding Author: Tel: +43-(0)1-4277-62511. Fax: +43-(0)1-4277-9623.
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Craik DJ. Host-defense activities of cyclotides. Toxins (Basel) 2012; 4:139-56. [PMID: 22474571 PMCID: PMC3317112 DOI: 10.3390/toxins4020139] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 01/25/2012] [Accepted: 01/31/2012] [Indexed: 11/27/2022] Open
Abstract
Cyclotides are plant mini-proteins whose natural function is thought to be to protect plants from pest or pathogens, particularly insect pests. They are approximately 30 amino acids in size and are characterized by a cyclic peptide backbone and a cystine knot arrangement of three conserved disulfide bonds. This article provides an overview of the reported pesticidal or toxic activities of cyclotides, discusses a possible common mechanism of action involving disruption of biological membranes in pest species, and describes methods that can be used to produce cyclotides for potential applications as novel pesticidal agents.
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Affiliation(s)
- David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
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Wang G. Post-translational Modifications of Natural Antimicrobial Peptides and Strategies for Peptide Engineering. ACTA ACUST UNITED AC 2012; 1:72-79. [PMID: 24511461 DOI: 10.2174/2211550111201010072] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Natural antimicrobial peptides (AMPs) are gene-coded defense molecules discovered in all the three life domains: Eubacteria, Archaea, and Eukarya. The latter covers protists, fungi, plants, and animals. It is now recognized that amino acid composition, peptide sequence, and post-translational modifications determine to a large extent the structure and function of AMPs. This article systematically describes post-translational modifications of natural AMPs annotated in the antimicrobial peptide database (http://aps.unmc.edu/AP). Currently, 1147 out of 1755 AMPs in the database are modified and classified into more than 17 types. Through chemical modifications, the peptides fold into a variety of structural scaffolds that target bacterial surfaces or molecules within cells. Chemical modifications also confer desired functions to a particular peptide. Meanwhile, these modifications modulate other peptide properties such as stability. Elucidation of the relationship between AMP property and chemical modification inspires peptide engineering. Depending on the objective of our design, peptides may be modified in various ways so that the desired features can be enhanced whereas unwanted properties can be minimized. Therefore, peptide design plays an essential role in developing natural AMPs into a new generation of therapeutic molecules.
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Affiliation(s)
- Guangshun Wang
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, 986495 Nebraska Medical Center, Omaha, NE 68198-6495, USA,
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Sando L, Henriques ST, Foley F, Simonsen SM, Daly NL, Hall KN, Gustafson KR, Aguilar MI, Craik DJ. A Synthetic mirror image of kalata B1 reveals that cyclotide activity is independent of a protein receptor. Chembiochem 2011; 12:2456-62. [PMID: 21928440 PMCID: PMC6364095 DOI: 10.1002/cbic.201100450] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Indexed: 11/08/2022]
Abstract
Featuring a circular, knotted structure and diverse bioactivities, cyclotides are a fascinating family of peptides that have inspired applications in drug design. Most likely evolved to protect plants against pests and herbivores, cyclotides also exhibit anti-cancer, anti-HIV, and hemolytic activities. In all of these activities, cell membranes appear to play an important role. However, the question of whether the activity of cyclotides depends on the recognition of chiral receptors or is primarily modulated by the lipid-bilayer environment has remained unknown. To determine the importance of lipid membranes on the activity of the prototypic cyclotide, kalata B1, we synthesized its all-D enantiomer and assessed its bioactivities. After the all-D enantiomer had been confirmed by (1)H NMR to be the structural mirror image of the native kalata B1, it was tested for anti-HIV activity, cytotoxicity, and hemolytic properties. The all-D peptide is active in these assays, albeit with less efficiency; this reveals that kalata B1 does not require chiral recognition to be active. The lower activity than the native peptide correlates with a lower affinity for phospholipid bilayers in model membranes. These results exclude a chiral receptor mechanism and support the idea that interaction with phospholipid membranes plays a role in the activity of kalata B1. In addition, studies with mixtures of L and D enantiomers of kalata B1 suggested that biological activity depends on peptide oligomerization at the membrane surface, which determines affinity for membranes by modulating the association-dissociation equilibrium.
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Affiliation(s)
- Lillian Sando
- Institute for Molecular Bioscience, The University of Queensland Brisbane, QLD, 4072 (Australia),
| | - Sónia Troeira Henriques
- Institute for Molecular Bioscience, The University of Queensland Brisbane, QLD, 4072 (Australia),
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa Av. Egas Moniz, 1649-028 Lisbon (Portugal)
| | - Fiona Foley
- Institute for Molecular Bioscience, The University of Queensland Brisbane, QLD, 4072 (Australia),
| | - Shane M. Simonsen
- Institute for Molecular Bioscience, The University of Queensland Brisbane, QLD, 4072 (Australia),
| | - Norelle L. Daly
- Institute for Molecular Bioscience, The University of Queensland Brisbane, QLD, 4072 (Australia),
| | - Kristopher N. Hall
- Department of Biochemistry and Molecular Biology, Monash University Victoria, 3800 Clayton (Australia)
| | - Kirk R. Gustafson
- Molecular Targets Laboratory, Center for Cancer Research National Cancer Institute at Frederick, Frederick, MD 21702 (USA)
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology, Monash University Victoria, 3800 Clayton (Australia)
| | - David J. Craik
- Institute for Molecular Bioscience, The University of Queensland Brisbane, QLD, 4072 (Australia),
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Nguyen GKT, Zhang S, Wang W, Wong CTT, Nguyen NTK, Tam JP. Discovery of a linear cyclotide from the bracelet subfamily and its disulfide mapping by top-down mass spectrometry. J Biol Chem 2011; 286:44833-44. [PMID: 21979955 DOI: 10.1074/jbc.m111.290296] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclotides are heat-stable macrocyclic peptides from plants that display a wide range of biological activities. They can be divided into two subfamilies: Möbius or bracelet, based on the presence or absence of a cis-proline residue in loop 5, respectively. Currently, over 150 cyclotides have been discovered, but only four linear variants of the Möbius subfamily have been hitherto isolated. In this study, we report the discovery of two novel cyclotides, hedyotide B1 and hedyotide B2, from the aerial parts of Hedyotis biflora. Hedyotide B1 has a cyclic cystine knot structure typical of cyclotides. Interestingly, hedyotide B2 possesses a linear backbone and is the first linear representative of the bracelet subfamily. Disulfide mapping of hedyotide B2 by a top-down MS/MS approach showed that it shares the same knotted disulfide arrangement as conventional cyclotides. Its unfolding pathway also showed that the penetrating disulfide bond Cys III-VI is the most stable disulfide linkage. Cloning of the gene encoding hedyotide B2 revealed a nonsense mutation that introduces a premature stop codon at the conserved Asn residue position, which is essential for an end-to-end backbone ligation. Biophysical characterization showed that hedyotide B2 was more susceptible to exopeptidase degradation as compared with hedyotide B1. Hedyotide B2 was also inactive against all four tested bacterial strains, whereas hedyotide B1 was bactericidal to Escherichia coli and Streptococcus salivarius at low micromolar concentration. Our results provide a deeper understanding of the structures, functions, and biosynthetic processing of cyclotides and uncyclotides in plants.
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Affiliation(s)
- Giang Kien Truc Nguyen
- From the School of Biological Sciences, Nanyang Technological University, Singapore 637551
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Cascales L, Henriques ST, Kerr MC, Huang YH, Sweet MJ, Daly NL, Craik DJ. Identification and characterization of a new family of cell-penetrating peptides: cyclic cell-penetrating peptides. J Biol Chem 2011; 286:36932-43. [PMID: 21873420 DOI: 10.1074/jbc.m111.264424] [Citation(s) in RCA: 138] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cell-penetrating peptides can translocate across the plasma membrane of living cells and thus are potentially useful agents in drug delivery applications. Disulfide-rich cyclic peptides also have promise in drug design because of their exceptional stability, but to date only one cyclic peptide has been reported to penetrate cells, the Momordica cochinchinensis trypsin inhibitor II (MCoTI-II). MCoTI-II belongs to the cyclotide family of plant-derived cyclic peptides that are characterized by a cyclic cystine knot motif. Previous studies in fixed cells showed that MCoTI-II could penetrate cells but kalata B1, a prototypic cyclotide from a separate subfamily of cyclotides, was bound to the plasma membrane and did not translocate into cells. Here, we show by live cell imaging that both MCoTI-II and kalata B1 can enter cells. Kalata B1 has the same cyclic cystine knot structural motif as MCoTI-II but differs significantly in sequence, and the mechanism by which these two peptides enter cells also differs. MCoTI-II appears to enter via macropinocytosis, presumably mediated by interaction of positively charged residues with phosphoinositides in the cell membrane, whereas kalata B1 interacts directly with the membrane by targeting phosphatidylethanolamine phospholipids, probably leading to membrane bending and vesicle formation. We also show that another plant-derived cyclic peptide, SFTI-1, can penetrate cells. SFTI-1 includes just 14 amino acids and, with the exception of its cyclic backbone, is structurally very different from the cyclotides, which are twice the size. Intriguingly, SFTI-1 does not interact with any of the phospholipids tested, and its mechanism of penetration appears to be distinct from MCoTI-II and kalata B1. The ability of diverse disulfide-rich cyclic peptides to penetrate cells enhances their potential in drug design, and we propose a new classification for them, i.e. cyclic cell-penetrating peptides.
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Affiliation(s)
- Laura Cascales
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
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