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Aslam L, Kaur R, Hussain S, Kapoor N, Mahajan R. LC-MS/MS identification and structural characterization of isolated cyclotides from precursor sequences of Viola odorata L. petiole tissue using computational approach. J Biosci 2022. [DOI: 10.1007/s12038-022-00283-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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2
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Falanga CM, Steinborn C, Muratspahić E, Zimmermann-Klemd AM, Winker M, Krenn L, Huber R, Gruber CW, Gründemann C. Ipecac root extracts and isolated circular peptides differentially suppress inflammatory immune response characterised by proliferation, activation and degranulation capacity of human lymphocytes in vitro. Biomed Pharmacother 2022; 152:113120. [PMID: 35653889 PMCID: PMC7614192 DOI: 10.1016/j.biopha.2022.113120] [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: 03/30/2022] [Accepted: 05/10/2022] [Indexed: 11/02/2022] Open
Abstract
Circular peptides are attractive lead compounds for drug development; this study investigates the immunomodulatory effects of defined root powder extracts and isolated peptides (called cyclotides) from Carapichea ipecacuanha (Brot.) L. Andersson ('ipecac'). Changes in the viability, proliferation and function of activated human primary T cells were analysed using flow cytometry-based assays. Three distinct peptide-enriched extracts of pulverised ipecac root material were prepared via C18 solid-phase extraction and analysed by reversed-phase HPLC and mass spectrometry. These extracts induced caspase 3/7 dependent apoptosis, thus leading to a suppressed proliferation of activated T cells and a reduction of the number of cells in the G2 phase. Furthermore, the stimulated T cells had a lower activation potential and a reduced degranulation capacity after treatment with ipecac extracts. Six different cyclotides were isolated from C. ipecacuanha and an T cell proliferation inhibiting effect was determined. Furthermore, the degranulation capacity of the T cells was diminished specifically by some cyclotides. In contrast to kalata B1 and its analog T20K, secretion of IL-2 and IFN- γ was not affected by any of the caripe cyclotides. The findings add to our increased understanding of the immunomodulating effects of cyclotides, and may provide a basis for the use of ipecac extracts for immunomodulation in conditions associated with an exessive immune responses.
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Affiliation(s)
- Chiara Madlen Falanga
- Center for Complementary Medicine, Department of Internal Medicine II, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Carmen Steinborn
- Center for Complementary Medicine, Department of Internal Medicine II, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Edin Muratspahić
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Amy Marisa Zimmermann-Klemd
- Translational Complementary Medicine, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Moritz Winker
- Translational Complementary Medicine, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Liselotte Krenn
- Department of Pharmacognosy, University of Vienna, Vienna, Austria
| | - Roman Huber
- Center for Complementary Medicine, Department of Internal Medicine II, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christian W. Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Carsten Gründemann
- Translational Complementary Medicine, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland.
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3
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Pandey A, Yadav R, Sanyal I. Evaluating the pesticidal impact of plant protease inhibitors: lethal weaponry in the co-evolutionary battle. PEST MANAGEMENT SCIENCE 2022; 78:855-868. [PMID: 34570437 DOI: 10.1002/ps.6659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/23/2021] [Accepted: 09/27/2021] [Indexed: 06/13/2023]
Abstract
In the arsenal of plant defense, protease inhibitors (PIs) are well-designed defensive products to counter field pests. PIs are produced in plant tissues by means of 'stable defense metabolite' and triggered on demand as the perception of the signal and well established as a part of plant active defense. PIs have been utilized for approximately four decades, initially as a gene-alone approach that was later replaced by multiple gene pyramiding/gene stacking due to insect adaptability towards the PI alone. By considering the adaptive responses of the pest to the single insecticidal gene, the concept of gene pyramiding gained continuous appreciation for the development of transgenic crops to deal with co-evolving pests. Gene pyramiding approaches are executed to bypass the insect's adaptive responses against PIs. Stacking PIs with additional insecticidal proteins, plastid engineering, recombinant proteinase inhibitors, RNAi-based methods and CRISPR/Cas9-mediated genome editing are the advanced tools and methods for next-generation pest management. Undoubtedly, the domain associated with the mechanism of PIs in the course of plant-pest interactions will occupy a central role for the advancement of more efficient and sustainable pest control strategies. © 2021 Society of Chemical Industry.
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Affiliation(s)
- Ankesh Pandey
- CSIR-National Botanical Research Institute, Lucknow, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Reena Yadav
- CSIR-National Botanical Research Institute, Lucknow, India
- Department of Biotechnology, Kumaun University, Nainital, India
| | - Indraneel Sanyal
- CSIR-National Botanical Research Institute, Lucknow, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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4
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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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5
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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: 39] [Impact Index Per Article: 9.8] [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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6
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Genome Mining as New Challenge in Natural Products Discovery. Mar Drugs 2020; 18:md18040199. [PMID: 32283638 PMCID: PMC7230286 DOI: 10.3390/md18040199] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 12/17/2022] Open
Abstract
Drug discovery is based on bioactivity screening of natural sources, traditionally represented by bacteria fungi and plants. Bioactive natural products and their secondary metabolites have represented the main source for new therapeutic agents, used as drug leads for new antibiotics and anticancer agents. After the discovery of the first biosynthetic genes in the last decades, the researchers had in their hands the tool to understand the biosynthetic logic and genetic basis leading to the production of these compounds. Furthermore, in the genomic era, in which the number of available genomes is increasing, genome mining joined to synthetic biology are offering a significant help in drug discovery. In the present review we discuss the importance of genome mining and synthetic biology approaches to identify new natural products, also underlining considering the possible advantages and disadvantages of this technique. Moreover, we debate the associated techniques that can be applied following to genome mining for validation of data. Finally, we review on the literature describing all novel natural drugs isolated from bacteria, fungi, and other living organisms, not only from the marine environment, by a genome-mining approach, focusing on the literature available in the last ten years.
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7
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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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8
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Reporting a Transcript from Iranian Viola Tricolor, Which May Encode a Novel Cyclotide-Like Precursor: Molecular and in silico Studies. Comput Biol Chem 2019; 84:107168. [PMID: 31791808 DOI: 10.1016/j.compbiolchem.2019.107168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/09/2019] [Accepted: 11/18/2019] [Indexed: 11/21/2022]
Abstract
The cyclotides are the largest known family of cyclic proteins, which are found in several plant families including Violaceae. They are circular bioactive peptides consisting of 28-37 amino acids, which possess a cyclic cystine knot (CCK) motif and could be useful in biotechnology and drug design as scaffolds for peptide-based drugs. This study describes our finding of a potentially novel gene transcript from the petals of the Iranian Viola tricolor (V. tricolor) flowers. This study is based on the cDNA screening method employed for isolation of cyclotide precursor genes and in silico analysis. Our study resulted in the finding of a novel cyclotide-like precursor from V. tricolor, which is documented in the NCBI by GenBank accession number: KP065812. The in silico analysis revealed that there are lots of similar sequences in many other plant families and they all exhibit some different features from previously discovered cyclotide precursors. The differences occur particularly in the main cyclotide domain that exists without the usual CCK structure. All of these hypothetical precursors have a conserved ER-signal sequence, a Cysteine (C)-rich sequence forming two zinc finger motifs and a cyclotide-like region containing several conserved elements including two highly conserved C residues. In conclusion, using the cDNA screening method we found a potentially new cyclotide-like precursor gene and in silico studies revealed its significant characteristics that may open up a new research line on the distribution and evolution of cyclotides.
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9
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Das K, Datta K, Karmakar S, Datta SK. Antimicrobial Peptides - Small but Mighty Weapons for Plants to Fight Phytopathogens. Protein Pept Lett 2019; 26:720-742. [PMID: 31215363 DOI: 10.2174/0929866526666190619112438] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 03/27/2019] [Accepted: 04/25/2019] [Indexed: 11/22/2022]
Abstract
Antimicrobial Peptides (AMPs) have diverse structures, varied modes of actions, and can inhibit the growth of a wide range of pathogens at low concentrations. Plants are constantly under attack by a wide range of phytopathogens causing massive yield losses worldwide. To combat these pathogens, nature has armed plants with a battery of defense responses including Antimicrobial Peptides (AMPs). These peptides form a vital component of the two-tier plant defense system. They are constitutively expressed as part of the pre-existing first line of defense against pathogen entry. When a pathogen overcomes this barrier, it faces the inducible defense system, which responds to specific molecular or effector patterns by launching an arsenal of defense responses including the production of AMPs. This review emphasizes the structural and functional aspects of different plant-derived AMPs, their homology with AMPs from other organisms, and how their biotechnological potential could generate durable resistance in a wide range of crops against different classes of phytopathogens in an environmentally friendly way without phenotypic cost.
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Affiliation(s)
- Kaushik Das
- Laboratory of Translational Research on Transgenic Crops, Department of Botany, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, West Bengal, India
| | - Karabi Datta
- Laboratory of Translational Research on Transgenic Crops, Department of Botany, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, West Bengal, India
| | - Subhasis Karmakar
- Laboratory of Translational Research on Transgenic Crops, Department of Botany, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, West Bengal, India
| | - Swapan K Datta
- Laboratory of Translational Research on Transgenic Crops, Department of Botany, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, West Bengal, India
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10
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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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11
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Hellinger R, Gruber CW. Peptide-based protease inhibitors from plants. Drug Discov Today 2019; 24:1877-1889. [PMID: 31170506 PMCID: PMC6753016 DOI: 10.1016/j.drudis.2019.05.026] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/03/2019] [Accepted: 05/29/2019] [Indexed: 02/08/2023]
Abstract
Proteases have an important role in homeostasis, and dysregulation of protease function can lead to pathogenesis. Therefore, proteases are promising drug targets in cancer, inflammation, and neurodegenerative disease research. Although there are well-established pharmaceuticals on the market, drug development for proteases is challenging. This is often caused by the limited selectivity of currently available lead compounds. Proteinaceous plant protease inhibitors are a diverse family of (poly)peptides that are important to maintain physiological homeostasis and to serve the innate defense machinery of the plant. In this review, we provide an overview of the diversity of plant peptide- and protein-based protease inhibitors (PIs), provide examples of such compounds that target human proteases, and discuss opportunities for these molecules in protease drug discovery and development.
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Affiliation(s)
- Roland Hellinger
- Center for Pharmacology and Physiology, Medical University of Vienna, Schwarzspanierstr. 17, 1090 Vienna, Austria
| | - Christian W Gruber
- Center for Pharmacology and Physiology, Medical University of Vienna, Schwarzspanierstr. 17, 1090 Vienna, Austria.
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12
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Fahradpour M, Keov P, Tognola C, Perez-Santamarina E, McCormick PJ, Ghassempour A, Gruber CW. Cyclotides Isolated from an Ipecac Root Extract Antagonize the Corticotropin Releasing Factor Type 1 Receptor. Front Pharmacol 2017; 8:616. [PMID: 29033832 PMCID: PMC5627009 DOI: 10.3389/fphar.2017.00616] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 08/23/2017] [Indexed: 12/22/2022] Open
Abstract
Cyclotides are plant derived, cystine-knot stabilized peptides characterized by their natural abundance, sequence variability and structural plasticity. They are abundantly expressed in Rubiaceae, Psychotrieae in particular. Previously the cyclotide kalata B7 was identified to modulate the human oxytocin and vasopressin G protein-coupled receptors (GPCRs), providing molecular validation of the plants' uterotonic properties and further establishing cyclotides as valuable source for GPCR ligand design. In this study we screened a cyclotide extract derived from the root powder of the South American medicinal plant ipecac (Carapichea ipecacuanha) for its GPCR modulating activity of the corticotropin-releasing factor type 1 receptor (CRF1R). We identified and characterized seven novel cyclotides. One cyclotide, caripe 8, isolated from the most active fraction, was further analyzed and found to antagonize the CRF1R. A nanomolar concentration of this cyclotide (260 nM) reduced CRF potency by ∼4.5-fold. In contrast, caripe 8 did not inhibit forskolin-, or vasopressin-stimulated cAMP responses at the vasopressin V2 receptor, suggesting a CRF1R-specific mode-of-action. These results in conjunction with our previous findings establish cyclotides as modulators of both classes A and B GPCRs. Given the diversity of cyclotides, our data point to other cyclotide-GPCR interactions as potentially important sources of drug-like molecules.
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Affiliation(s)
- Mohsen Fahradpour
- Center for Physiology and Pharmacology, Medical University of ViennaVienna, Austria.,Medicinal Plants and Drugs Research Institute, Shahid Beheshti UniversityTehran, Iran
| | - Peter Keov
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, BrisbaneQLD, Australia
| | - Carlotta Tognola
- Center for Physiology and Pharmacology, Medical University of ViennaVienna, Austria
| | | | - Peter J McCormick
- School of Veterinary Medicine, University of SurreyGuildford, United Kingdom
| | - Alireza Ghassempour
- Medicinal Plants and Drugs Research Institute, Shahid Beheshti UniversityTehran, Iran
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of ViennaVienna, Austria.,Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, BrisbaneQLD, Australia
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Abstract
Cyclotides are globular microproteins with a unique head-to-tail cyclized backbone, stabilized by three disulfide bonds forming a cystine knot. This unique circular backbone topology and knotted arrangement of three disulfide bonds makes them exceptionally stable to chemical, thermal, and biological degradation compared to other peptides of similar size. In addition, cyclotides have been shown to be highly tolerant to sequence variability, aside from the conserved residues forming the cystine knot. Cyclotides can also cross cellular membranes and are able to modulate intracellular protein-protein interactions, both in vitro and in vivo. All of these features make cyclotides highly promising as leads or frameworks for the design of peptide-based diagnostic and therapeutic tools. This article provides an overview on cyclotides and their applications as molecular imaging agents and peptide-based therapeutics.
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Affiliation(s)
- Andrew Gould
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90089-9121, USA
| | - Julio A. Camarero
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90089-9121, USA
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089-9121, USA
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14
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Abstract
Urease from Canavalia ensiformis seeds was the first enzyme ever to be crystallized, in 1926. These proteins, found in plants, bacteria and fungi, present different biological properties including catalytic hydrolysis of urea, and also enzyme-independent activities, such as induction of exocytosis, pro-inflammatory effects, neurotoxicity, antifungal and insecticidal properties. Urease is toxic to insects and fungi per se but part of this toxicity relies on an internal peptide (~11 kDa), which is released upon digestion of the protein by insect enzymes. A recombinant form of this peptide, called jaburetox (JBTX), was constructed using jbureII gene as a template. The peptide exhibits liposome disruption properties, and insecticidal and fungicidal activities. Here we review the known biological properties activities of JBTX, and comment on new ones not yet fully characterized. JBTX was able to cause mortality of Aedes aegypti larvae in a feeding assay whereas in a dose as low as of 0.1 μg it provoked death of Triatoma infestans bugs. JBTX (10−5–10−6 M) inhibits the growth of E. coli, P. aeruginosa and B. cereus after 24 h incubation. Multilamellar liposomes interacting with JBTX undergo reorganization of the membrane’s lipids as detected by small angle X-ray scattering (SAXS) studies. Encapsulating JBTX into lipid nanoparticles led to an increase of the peptide’s antifungal activity. Transgenic tobacco and sugarcane plants expressing the insecticidal peptide JBTX, showed increased resistance to attack of the insect pests Spodoptera frugiperda, Diatraea saccharalis and Telchin licus licus. Many questions remain unanswered; however, so far, JBTX has shown to be a versatile peptide that can be used against various insect and fungus species, and in new bacterial control strategies.
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Affiliation(s)
- Arlete Beatriz Becker-Ritt
- Graduate Program in Cellular and Molecular Biology Applied to Health, Lutheran University of Brazil (ULBRA), Canoas, RS Brazil
| | - Camila Saretta Portugal
- Graduate Program in Cellular and Molecular Biology Applied to Health, Lutheran University of Brazil (ULBRA), Canoas, RS Brazil
| | - Célia Regina Carlini
- Brain Institute (Instituto do Cérebro-INSCER), Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, RS Brazil
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15
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Ravipati AS, Poth AG, Troeira Henriques S, Bhandari M, Huang YH, Nino J, Colgrave ML, Craik DJ. Understanding the Diversity and Distribution of Cyclotides from Plants of Varied Genetic Origin. JOURNAL OF NATURAL PRODUCTS 2017; 80:1522-1530. [PMID: 28471681 DOI: 10.1021/acs.jnatprod.7b00061] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Cyclotides are a large family of naturally occurring plant-derived macrocyclic cystine-knot peptides, with more than 400 having been identified in species from the Violaceae, Rubiaceae, Cucurbitaceae, Fabaceae, and Solanaceae families. Nevertheless, their specialized distribution within the plant kingdom remains poorly understood. In this study, the diversity of cyclotides was explored through the screening of 197 plants belonging to 43 different families. In total, 28 cyclotides were sequenced from 15 plant species, one of which belonged to the Rubiaceae and 14 to the Violaceae. Every Violaceae species screened contained cyclotides, but they were only sparsely represented in Rubiaceae and nonexistent in other families. The study thus supports the hypothesis that cyclotides are ubiquitous in the Violaceae, and it adds to the list of plants found to express kalata S and cycloviolacin O12. Finally, previous studies suggested the existence of cyclotide isoforms with either an Asn or an Asp at the C-terminal processing site of the cyclotide domain within the precursor proteins. Here we found that despite the discovery of a few cyclotides genuinely containing an Asp in loop 6 as evidenced by gene sequencing, deamidation of Asn during enzymatic digestion resulted in the artifactual presence of Asp isoforms. This result is consistent with studies suggesting that peptides can undergo deamidation after being subjected to external factors, including pH, temperature, and enzymatic digestion.
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Affiliation(s)
- Anjaneya S Ravipati
- Institute for Molecular Bioscience, The University of Queensland , Brisbane 4072, Queensland Australia
| | - Aaron G Poth
- Institute for Molecular Bioscience, The University of Queensland , Brisbane 4072, Queensland Australia
| | - Sónia Troeira Henriques
- Institute for Molecular Bioscience, The University of Queensland , Brisbane 4072, Queensland Australia
| | - Murari Bhandari
- Institute for Molecular Bioscience, The University of Queensland , Brisbane 4072, Queensland Australia
| | - Yen-Hua Huang
- Institute for Molecular Bioscience, The University of Queensland , Brisbane 4072, Queensland Australia
| | - Jaime Nino
- Universidad Tecnológica de Pereira , Cra 27 No 10-02-Los Álamos, Pereira, Risaralda, Colombia
| | - Michelle L Colgrave
- Commonwealth Scientific and Industrial Research Organization, Agriculture and Food, St Lucia 4067, Queensland, Australia
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland , Brisbane 4072, Queensland Australia
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16
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Maestri E, Marmiroli M, Marmiroli N. Bioactive peptides in plant-derived foodstuffs. J Proteomics 2016; 147:140-155. [DOI: 10.1016/j.jprot.2016.03.048] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/14/2016] [Accepted: 03/29/2016] [Indexed: 01/07/2023]
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17
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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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18
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Attah AF, Hellinger R, Sonibare MA, Moody JO, Arrowsmith S, Wray S, Gruber CW. Ethnobotanical survey of Rinorea dentata (Violaceae) used in South-Western Nigerian ethnomedicine and detection of cyclotides. JOURNAL OF ETHNOPHARMACOLOGY 2016; 179:83-91. [PMID: 26721222 PMCID: PMC5858781 DOI: 10.1016/j.jep.2015.12.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 12/18/2015] [Accepted: 12/21/2015] [Indexed: 05/23/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE People living in the tropical rain forest of South-Western Nigeria use Rinorea dentata (P. Beauv.) Kuntze (Violaceae) in ethno-veterinary medicine to facilitate parturition. There are no evidence-based pharmacological investigations for the uterotonic activity of this plant. AIMS OF STUDY (i) Collection of data about the ethnopharmacological uses of R. dentata and evaluation of its uses and applications in health care; (ii) determining potential uterotonic effects in vitro, and (iii) chemical characterization of R. dentata, which is a member of the Violaceae family known to express circular cystine-knot peptides, called cyclotides. MATERIALS AND METHODS The ethnopharmacological use of R. dentata in settlement camps within the area J4 of Omo forest has been investigated by semi-structured questionnaires and open interviews. Use index analysis has been performed by seven quantitative statistical models. Respondents' claim on the beneficial ethno-veterinary application of the plant to aid parturition has been investigated in vitro by myometrial contractility organ bath assays. The bioactive plant extract was screened by chemical derivatization and mass spectrometry-based peptidomics using reversed-phase HPLC fractionation and MALDI-TOF/TOF analysis. RESULTS Based on the survey analysis, medicinal preparations of R. dentata have been used for anti-microbial and anti-malaria purpose in humans, and for aiding parturition in farm animals. The latter application was mentioned by one out of six respondents who claimed to use this plant for any medicinal purpose. The plant extract exhibited a weak uterotonic effect using organ bath studies. The plant contains cyclotides and the peptide riden A has been identified by de novo amino acid sequencing using mass spectrometry. CONCLUSION Few dwellers around the settlement camps of the tropical forest of Omo (Nigeria) use R. dentata for various health problems in traditional veterinary and human medicine. The weak uterotonic effect of the cyclotide-rich extract is in agreement with the low use value index obtained for this plant. Cyclotides have been reported in the genus Rinorea confirming the ubiquitous expression of these stable bioactive plant peptides within the family of Violaceae.
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Affiliation(s)
- Alfred F Attah
- Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria; Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstr. 17, A-1090 Vienna, Austria
| | - Roland Hellinger
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstr. 17, A-1090 Vienna, Austria
| | - Mubo A Sonibare
- Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria
| | - Jones O Moody
- Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria
| | - Sarah Arrowsmith
- Department of Cellular and Molecular Physiology, Harris-Wellbeing Preterm Birth Centre, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Susan Wray
- Department of Cellular and Molecular Physiology, Harris-Wellbeing Preterm Birth Centre, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstr. 17, A-1090 Vienna, Austria; School of Biomedical Sciences, The University of Queensland, Brisbane, Qld 4072, Australia.
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19
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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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20
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Koehbach J, Gruber CW. From ethnopharmacology to drug design. Commun Integr Biol 2014; 6:e27583. [PMID: 24567782 DOI: 10.4161/cib.27583] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 12/19/2013] [Indexed: 12/25/2022] Open
Abstract
Nature's diversity is one of the biggest resources of therapeutic lead compounds. Traditionally-used herbal remedies harbor a variety of bioactive compounds providing researchers with starting points for drug development. Ethnopharmacological investigations of uterotonic plant preparations identified a class of circular and disulfide-rich peptides, called cyclotides, to exhibit strong uterine contractions. In humans one of the physiological regulators of the myometrial contractility is the nonapeptide oxytocin acting on its cognate G protein-coupled receptors. They are considered to represent one of the most promising drug targets with ~30% of all currently marketed drugs acting on these transmembrane receptors. Based on observed similarities regarding the activity and structure of plant cyclotides with human oxytocin we analyzed the pharmacological principle of their action and identified the oxytocin and vasopressin 1a receptors as molecular targets of cyclotides from the Rubiaceae plant Oldenlandia affinis. Using a synthetic approach, the sequence of the native cyclotide kalata B7 was used to design oxytocin-like nonapeptides with nanomolar affinity and selectivity for the oxytocin receptor. This provides formal proof for the use of cyclotides as templates in peptide ligand design. At a more general level, mining of naturally-occurring peptides is a promising tool for the identification and the design of novel G protein-coupled receptor ligands.
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Affiliation(s)
- Johannes Koehbach
- Center for Physiology and Pharmacology; Medical University of Vienna; Vienna, Austria
| | - Christian W Gruber
- Center for Physiology and Pharmacology; Medical University of Vienna; Vienna, Austria
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21
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Nawrot R, Barylski J, Nowicki G, Broniarczyk J, Buchwald W, Goździcka-Józefiak A. Plant antimicrobial peptides. Folia Microbiol (Praha) 2013; 59:181-96. [PMID: 24092498 PMCID: PMC3971460 DOI: 10.1007/s12223-013-0280-4] [Citation(s) in RCA: 219] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 09/17/2013] [Indexed: 12/27/2022]
Abstract
Plant antimicrobial peptides (AMPs) are a component of barrier defense system of plants. They have been isolated from roots, seeds, flowers, stems, and leaves of a wide variety of species and have activities towards phytopathogens, as well as against bacteria pathogenic to humans. Thus, plant AMPs are considered as promising antibiotic compounds with important biotechnological applications. Plant AMPs are grouped into several families and share general features such as positive charge, the presence of disulfide bonds (which stabilize the structure), and the mechanism of action targeting outer membrane structures.
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Affiliation(s)
- Robert Nawrot
- Department of Molecular Virology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University in Poznan, Umultowska 89, 61-614, Poznan, Poland,
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22
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Gerlach SL, Göransson U, Kaas Q, Craik DJ, Mondal D, Gruber CW. A systematic approach to document cyclotide distribution in plant species from genomic, transcriptomic, and peptidomic analysis. Biopolymers 2013; 100:433-7. [DOI: 10.1002/bip.22258] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 03/26/2013] [Accepted: 04/08/2013] [Indexed: 01/15/2023]
Affiliation(s)
- Samantha L. Gerlach
- Department of Pharmacology; School of Medicine; Tulane University; 1430 Tulane Ave New Orleans LA 70112
| | - Ulf Göransson
- Division of Pharmacognosy, Department of Medicinal Chemistry; Uppsala University; Biomedical Centre 574 S-75123 Uppsala Sweden
| | - Quentin Kaas
- Division of Chemistry and Structural Biology; Institute for Molecular Bioscience; University of Queensland; Brisbane Queensland 4072 Australia
| | - David J. Craik
- Division of Chemistry and Structural Biology; Institute for Molecular Bioscience; University of Queensland; Brisbane Queensland 4072 Australia
| | - Debasis Mondal
- Department of Pharmacology; School of Medicine; Tulane University; 1430 Tulane Ave New Orleans LA 70112
| | - Christian W. Gruber
- Center for Physiology and Pharmacology; Medical University of Vienna; Schwarzspanierstr. 17 1090 Vienna Austria
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23
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Koehbach J, Attah AF, Berger A, Hellinger R, Kutchan TM, Carpenter EJ, Rolf M, Sonibare MA, Moody JO, Ka-Shu Wong G, Dessein S, Greger H, Gruber CW. Cyclotide discovery in Gentianales revisited--identification and characterization of cyclic cystine-knot peptides and their phylogenetic distribution in Rubiaceae plants. Biopolymers 2013; 100:438-52. [PMID: 23897543 PMCID: PMC3816352 DOI: 10.1002/bip.22328] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 06/07/2013] [Indexed: 11/06/2022]
Abstract
Cyclotides are a unique class of ribosomally synthesized cysteine-rich miniproteins characterized by a head-to-tail cyclized backbone and three conserved disulfide-bonds in a knotted arrangement. Originally they were discovered in the coffee-family plant Oldenlandia affinis (Rubiaceae) and have since been identified in several species of the violet, cucurbit, pea, potato, and grass families. However, the identification of novel cyclotide-containing plant species still is a major challenge due to the lack of a rapid and accurate analytical workflow in particular for large sampling numbers. As a consequence, their phylogeny in the plant kingdom remains unclear. To gain further insight into the distribution and evolution of plant cyclotides, we analyzed ∼300 species of >40 different families, with special emphasis on plants from the order Gentianales. For this purpose, we have developed a refined screening methodology combining chemical analysis of plant extracts and bioinformatic analysis of transcript databases. Using mass spectrometry and transcriptome-mining, we identified nine novel cyclotide-containing species and their related cyclotide precursor genes in the tribe Palicoureeae. The characterization of novel peptide sequences underlines the high variability and plasticity of the cyclotide framework, and a comparison of novel precursor proteins from Carapichea ipecacuanha illustrated their typical cyclotide gene architectures. Phylogenetic analysis of their distribution within the Psychotria alliance revealed cyclotides to be restricted to Palicourea, Margaritopsis, Notopleura, Carapichea, Chassalia, and Geophila. In line with previous reports, our findings confirm cyclotides to be one of the largest peptide families within the plant kingdom and suggest that their total number may exceed tens of thousands.
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Affiliation(s)
- Johannes Koehbach
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria
| | - Alfred F. Attah
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria
- Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria
| | - Andreas Berger
- Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Roland Hellinger
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria
| | | | - Eric J. Carpenter
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
- Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Megan Rolf
- Donald Danforth Plant Science Center, St. Louis, MO
| | - Mubo A. Sonibare
- Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria
| | - Jones O. Moody
- Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria
| | - Gane Ka-Shu Wong
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
- Department of Medicine, University of Alberta, Edmonton, AB, Canada
- BGI-Shenzhen, Bei Shan Industrial Zone, Yantian District, Shenzhen, China
| | - Steven Dessein
- National Botanic Garden of Belgium, Domein van Bouchout, 1860 Meise, Belgium
| | - Harald Greger
- Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Christian W. Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria
- Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
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24
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Gründemann C, Thell K, Lengen K, Garcia-Käufer M, Huang YH, Huber R, Craik DJ, Schabbauer G, Gruber CW. Cyclotides Suppress Human T-Lymphocyte Proliferation by an Interleukin 2-Dependent Mechanism. PLoS One 2013; 8:e68016. [PMID: 23840803 PMCID: PMC3694003 DOI: 10.1371/journal.pone.0068016] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 05/24/2013] [Indexed: 02/07/2023] Open
Abstract
Cyclotides are a diverse and abundant group of ribosomally synthesized plant peptides containing a unique cyclic cystine-knotted topology that confers them with remarkable stability. Kalata B1, a representative member of this family of mini-proteins, has been found to inhibit the proliferation of human peripheral blood mononuclear cells. Analysis of T-cell proliferation upon treatment with chemically synthesized kalata B1 mutants revealed a region comprising inter-cysteine loops 1 and 2 of the cyclotide framework to be important for biological activity. Cytokine signaling analysis using an 'active' kalata B1 mutant [T20K], and the reference drug cyclosporin A (CsA) demonstrated that treatment of activated T-lymphocytes with these compounds decreased the expression of the interleukin-2 (IL-2) surface receptor as well as IL-2 cytokine secretion and IL-2 gene expression, whereas the 'inactive' kalata B1 mutant [V10K] did not cause any effects. The anti-proliferative activity of [T20K] kalata B1 was antagonized by addition of exogenous IL-2. Furthermore, treatment with [T20K] kalata B1 led to an initial reduction of the effector function, as indicated by the reduced IFN-γ and TNF-α production, but the levels of both cytokines stabilized over time and returned to their normal levels. On the other hand, the degranulation activity remained reduced. This indicated that cyclotides interfere with T-cell polyfunctionality and arrest the proliferation of immune-competent cells through inhibiting IL-2 biology at more than one site. The results open new avenues to utilize native and synthetically-optimized cyclotides for applications in immune-related disorders and as immunosuppressant peptides.
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Affiliation(s)
- Carsten Gründemann
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- Center for Complementary Medicine, Department of Environmental Health Sciences, University Medical Center Freiburg, Freiburg, Germany
| | - Kathrin Thell
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Karin Lengen
- Center for Complementary Medicine, Department of Environmental Health Sciences, University Medical Center Freiburg, Freiburg, Germany
| | - Manuel Garcia-Käufer
- Center for Complementary Medicine, Department of Environmental Health Sciences, University Medical Center Freiburg, Freiburg, Germany
| | - Yen-Hua Huang
- Institute for Molecular Bioscience, the University of Queensland, Brisbane, Queensland, Australia
| | - Roman Huber
- Center for Complementary Medicine, Department of Environmental Health Sciences, University Medical Center Freiburg, Freiburg, Germany
| | - David J. Craik
- Institute for Molecular Bioscience, the University of Queensland, Brisbane, Queensland, Australia
| | - Gernot Schabbauer
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Christian W. Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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25
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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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26
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Craik DJ. Joseph Rudinger memorial lecture: discovery and applications of cyclotides. J Pept Sci 2013; 19:393-407. [PMID: 23737440 DOI: 10.1002/psc.2523] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 05/02/2013] [Indexed: 12/31/2022]
Abstract
Cyclotides are plant-derived peptides of approximately 30 amino acids that have the characteristic structural features of a head-to-tail cyclized backbone and a cystine knot arrangement of their three conserved disulfide bonds. This article gives a personal account of the discovery of cyclotides, their characterization and their applications, based on work carried out in my laboratory over the last 20 years. It describes some of the background to their discovery and focuses on how their unique structural features lead to exceptional stability. This stability and their amenability to chemical synthesis have made it possible to use cyclotides as templates in protein engineering and drug design applications. These applications complement the interest in cyclotides deriving from their unique structures and natural function as host defense molecules.
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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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27
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Conibear AC, Daly NL, Craik DJ. Quantification of small cyclic disulfide-rich peptides. Biopolymers 2012. [DOI: 10.1002/bip.22121] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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28
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Hashempour H, Koehbach J, Daly NL, Ghassempour A, Gruber CW. Characterizing circular peptides in mixtures: sequence fragment assembly of cyclotides from a violet plant by MALDI-TOF/TOF mass spectrometry. Amino Acids 2012; 44:581-95. [PMID: 22890611 PMCID: PMC3549257 DOI: 10.1007/s00726-012-1376-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 07/20/2012] [Indexed: 11/29/2022]
Abstract
Cyclotides are a very abundant class of plant peptides that display significant sequence variability around a conserved cystine-knot motif and a head-to-tail cyclized backbone conferring them with remarkable stability. Their intrinsic bioactivities combined with tools of peptide engineering make cyclotides an interesting template for the design of novel agrochemicals and pharmaceuticals. However, laborious isolation and purification prior to de novo sequencing limits their discovery and hence their use as scaffolds for peptide-based drug development. Here we extend the knowledge about their sequence diversity by analysing the cyclotide content of a violet species native to Western Asia and the Caucasus region. Using an experimental approach, which was named sequence fragment assembly by MALDI-TOF/TOF, it was possible to characterize 13 cyclotides from Viola ignobilis, whereof ten (vigno 1–10) display previously unknown sequences. Amino acid sequencing of various enzymatic digests of cyclotides allowed the accurate assembly and alignment of smaller fragments to elucidate their primary structure, even when analysing mixtures containing multiple peptides. As a model to further dissect the combinatorial nature of the cyclotide scaffold, we employed in vitro oxidative refolding of representative vigno cyclotides and confirmed the high dependency of folding yield on the inter-cysteine loop sequences. Overall this work highlights the immense structural diversity and plasticity of the unique cyclotide framework. The presented approach for the sequence analysis of peptide mixtures facilitates and accelerates the discovery of novel plant cyclotides.
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Affiliation(s)
- Hossein Hashempour
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria
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29
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Gruber CW, Muttenthaler M. Discovery of defense- and neuropeptides in social ants by genome-mining. PLoS One 2012; 7:e32559. [PMID: 22448224 PMCID: PMC3308954 DOI: 10.1371/journal.pone.0032559] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 01/29/2012] [Indexed: 11/18/2022] Open
Abstract
Natural peptides of great number and diversity occur in all organisms, but analyzing their peptidome is often difficult. With natural product drug discovery in mind, we devised a genome-mining approach to identify defense- and neuropeptides in the genomes of social ants from Atta cephalotes (leaf-cutter ant), Camponotus floridanus (carpenter ant) and Harpegnathos saltator (basal genus). Numerous peptide-encoding genes of defense peptides, in particular defensins, and neuropeptides or regulatory peptide hormones, such as allatostatins and tachykinins, were identified and analyzed. Most interestingly we annotated genes that encode oxytocin/vasopressin-related peptides (inotocins) and their putative receptors. This is the first piece of evidence for the existence of this nonapeptide hormone system in ants (Formicidae) and supports recent findings in Tribolium castaneum (red flour beetle) and Nasonia vitripennis (parasitoid wasp), and therefore its confinement to some basal holometabolous insects. By contrast, the absence of the inotocin hormone system in Apis mellifera (honeybee), another closely-related member of the eusocial Hymenoptera clade, establishes the basis for future studies on the molecular evolution and physiological function of oxytocin/vasopressin-related peptides (vasotocin nonapeptide family) and their receptors in social insects. Particularly the identification of ant inotocin and defensin peptide sequences will provide a basis for future pharmacological characterization in the quest for potent and selective lead compounds of therapeutic value.
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Affiliation(s)
- Christian W Gruber
- Medical University of Vienna, Center for Physiology and Pharmacology, Vienna, Austria.
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30
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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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Poth AG, Colgrave ML, Philip R, Kerenga B, Daly NL, Anderson MA, Craik DJ. Discovery of cyclotides in the fabaceae plant family provides new insights into the cyclization, evolution, and distribution of circular proteins. ACS Chem Biol 2011; 6:345-55. [PMID: 21194241 DOI: 10.1021/cb100388j] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclotides are plant proteins whose defining structural features are a head-to-tail cyclized backbone and three interlocking disulfide bonds, which in combination are known as a cyclic cystine knot. This unique structural motif confers cyclotides with exceptional resistance to proteolysis. Their endogenous function is thought to be as plant defense agents, associated with their insecticidal and larval growth-inhibitory properties. However, in addition, an array of pharmaceutically relevant biological activities has been ascribed to cyclotides, including anti-HIV, anthelmintic, uterotonic, and antimicrobial effects. So far, >150 cyclotides have been elucidated from members of the Rubiaceae, Violaceae, and Cucurbitaceae plant families, but their wider distribution among other plant families remains unclear. Clitoria ternatea (Butterfly pea) is a member of plant family Fabaceae and through its usage in traditional medicine to aid childbirth bears similarity to Oldenlandia affinis, from which many cyclotides have been isolated. Using a combination of nanospray and matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) analyses, we examined seed extracts of C. ternatea and discovered cyclotides in the Fabaceae, the third-largest family of flowering plants. We characterized 12 novel cyclotides, thus expanding knowledge of cyclotide distribution and evolution within the plant kingdom. The discovery of cyclotides containing novel sequence motifs near the in planta cyclization site has provided new insights into cyclotide biosynthesis. In particular, MS analyses of the novel cyclotides from C. ternatea suggest that Asn to Asp variants at the cyclization site are more common than previously recognized. Moreover, this study provides impetus for the examination of other economically and agriculturally significant species within Fabaceae, now the largest plant family from which cyclotides have been described.
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Affiliation(s)
- Aaron G. Poth
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia
- CSIRO Livestock Industries, St. Lucia, QLD, Australia
| | | | - Reynold Philip
- Department of Chemistry, University of Papua New Guinea, Port Moresby, Papua New Guinea
| | - Bomai Kerenga
- Department of Chemistry, University of Papua New Guinea, Port Moresby, Papua New Guinea
| | - Norelle L. Daly
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia
| | | | - David J. Craik
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia
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Abstract
Abnormalities in the process of uterine muscle contractility during pregnancy and birth can have major clinical implications, including preterm labour, which is the single largest cause of maternal and prenatal mortality in the Western world and a major contributor to childhood developmental problems. In contrast, induction of labour may be necessary in certain conditions. Currently used interventional therapies to suppress (tocolytic agents) or to induce (uterotonic agents) uterine contractions lack potency and/or selectivity and can have harmful side effects for mother and baby. Nature's diversity has always been, and still is, one of the biggest resources of therapeutic lead compounds. Many natural products exhibit biological activity against unrelated targets, thus providing researchers with starting points for drug development. In this review we will provide an overview of uterine muscle physiology, describe currently available biological screening procedures for testing of uterotonic plant compounds and will summarise traditionally-used uterotonic plants, their active components and their mechanisms, primarily focusing on uterotonic active circular plant peptides called cyclotides. Finally we will comment on the discovery of novel cyclotide-producing plant species and the possibility for the development of novel plant-derived uterotonic and tocolytic drugs.
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Conlan BF, Gillon AD, Craik DJ, Anderson MA. Circular proteins and mechanisms of cyclization. Biopolymers 2010; 94:573-83. [DOI: 10.1002/bip.21422] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Kaas Q, Craik DJ. Analysis and classification of circular proteins in CyBase. Biopolymers 2010; 94:584-91. [DOI: 10.1002/bip.21424] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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