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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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52
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Qian Cutrone J(J, Huang X(S, Kozlowski ES, Bao Y, Wang Y, Poronsky CS, Drexler DM, Tymiak AA. Tiered analytics for purity assessment of macrocyclic peptides in drug discovery: Analytical consideration and method development. J Pharm Biomed Anal 2017; 138:166-174. [DOI: 10.1016/j.jpba.2017.01.056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 01/22/2017] [Accepted: 01/29/2017] [Indexed: 10/20/2022]
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53
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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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Molesini B, Treggiari D, Dalbeni A, Minuz P, Pandolfini T. Plant cystine-knot peptides: pharmacological perspectives. Br J Clin Pharmacol 2017; 83:63-70. [PMID: 26987851 PMCID: PMC5338163 DOI: 10.1111/bcp.12932] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/07/2016] [Accepted: 03/09/2016] [Indexed: 12/29/2022] Open
Abstract
Cystine-knot miniproteins are a class of 30-50 amino acid long peptides widespread in eukaryotic organisms. Due to their very peculiar three-dimensional structure, they exhibit high resistance to heat and peptidase attack. The cystine-knot peptides are well represented in several plant species including medicinal herbs and crops. The pharmacological interest in plant cystine-knot peptides derives from their broad biological activities, mainly cytotoxic, antimicrobial and peptidase inhibitory and in the possibility to engineer them to incorporate pharmacophoric information for oral delivery or disease biomonitoring. The mechanisms of action of plant cystine-knot peptides are still largely unknown, although the capacity to interfere with plasma membranes seems a feature common to several cystine-knot peptides. In some cases, such as potato carboxypetidase inhibitor (PCI) and tomato cystine-knot miniproteins (TCMPs), the cystine-knot peptides target human growth factor receptors either by acting as growth factor antagonist or by altering their signal transduction pathway. The possibility to identify specific molecular targets of plant cystine-knot peptides in human cells opens novel possibilities for the pharmacological use of these peptides besides their use as scaffold to develop stable disease molecular markers and therapeutic agents.
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Affiliation(s)
| | - Davide Treggiari
- Department of Medicine, Section of Internal MedicineUniversity of VeronaVeronaItaly
| | - Andrea Dalbeni
- Department of Medicine, Section of Internal MedicineUniversity of VeronaVeronaItaly
| | - Pietro Minuz
- Department of Medicine, Section of Internal MedicineUniversity of VeronaVeronaItaly
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55
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Thomas AS, Saravanakumar R, Gupta PV. Evaluation of cytotoxic activity of protein extracts from the leaves of Morinda pubescens on human cancer cell lines. REVISTA BRASILEIRA DE FARMACOGNOSIA-BRAZILIAN JOURNAL OF PHARMACOGNOSY 2017. [DOI: 10.1016/j.bjp.2016.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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56
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Park S, Yoo KO, Marcussen T, Backlund A, Jacobsson E, Rosengren KJ, Doo I, Göransson U. Cyclotide Evolution: Insights from the Analyses of Their Precursor Sequences, Structures and Distribution in Violets ( Viola). FRONTIERS IN PLANT SCIENCE 2017; 8:2058. [PMID: 29326730 PMCID: PMC5741643 DOI: 10.3389/fpls.2017.02058] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/17/2017] [Indexed: 05/20/2023]
Abstract
Cyclotides are a family of plant proteins that are characterized by a cyclic backbone and a knotted disulfide topology. Their cyclic cystine knot (CCK) motif makes them exceptionally resistant to thermal, chemical, and enzymatic degradation. By disrupting cell membranes, the cyclotides function as host defense peptides by exhibiting insecticidal, anthelmintic, antifouling, and molluscicidal activities. In this work, we provide the first insight into the evolution of this family of plant proteins by studying the Violaceae, in particular species of the genus Viola. We discovered 157 novel precursor sequences by the transcriptomic analysis of six Viola species: V. albida var. takahashii, V. mandshurica, V. orientalis, V. verecunda, V. acuminata, and V. canadensis. By combining these precursor sequences with the phylogenetic classification of Viola, we infer the distribution of cyclotides across 63% of the species in the genus (i.e., ~380 species). Using full precursor sequences from transcriptomes, we show an evolutionary link to the structural diversity of the cyclotides, and further classify the cyclotides by sequence signatures from the non-cyclotide domain. Also, transcriptomes were compared to cyclotide expression on a peptide level determined using liquid chromatography-mass spectrometry. Furthermore, the novel cyclotides discovered were associated with the emergence of new biological functions.
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Affiliation(s)
- Sungkyu Park
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Ki-Oug Yoo
- Department of Biological Sciences, Kangwon National University, Chuncheon, South Korea
| | - Thomas Marcussen
- Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, Oslo, Norway
| | - Anders Backlund
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Erik Jacobsson
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - K. Johan Rosengren
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Inseok Doo
- Biotech Research Team, Biotech Research Center of Dong-A Pharm Co Ltd., Seoul, South Korea
| | - Ulf Göransson
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
- *Correspondence: Ulf Göransson
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57
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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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58
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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: 75] [Impact Index Per Article: 9.4] [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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59
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Camarero JA, Kimura RH, Woo YH, Shekhtman A, Cantor J. Biosynthesis of a fully functional cyclotide inside living bacterial cells. Chembiochem 2016; 8:1363-6. [PMID: 17590879 DOI: 10.1002/cbic.200700183] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Julio A Camarero
- Lawrence Livermore National Laboratory, University of California, 7000 East Avenue, L-231, Livermore, CA 94550, USA.
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60
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Rosengren KJ, Daly NL, Harvey PJ, Craik DJ. The self-association of the cyclotide kalata B2 in solution is guided by hydrophobic interactions. Biopolymers 2016; 100:453-60. [PMID: 23893463 DOI: 10.1002/bip.22269] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 04/17/2013] [Accepted: 04/19/2013] [Indexed: 01/28/2023]
Abstract
The cyclotides are a family of small head-to-tail cyclic plant defense proteins. In addition to their cyclic backbone, cyclotides comprise three disulfide bonds in a knotted arrangement, resulting in a highly cross-braced structure that provides exceptional chemical and proteolytic stability. A number of bioactivities have been associated with cyclotides, including insecticidal, antimicrobial, anti-viral and cytotoxic, and these activities are related to an ability to target and disrupt biological membranes. Kalata B2 and to a lesser extent kalata B1, isolated from Oldenlandia affinis, self-associate to tetramers and octamers in aqueous buffers, and this oligomerization has been suggested to be relevant for their ability to form pores in membranes. Here we demonstrate by solution NMR spectroscopy analysis that the oligomerization of kalata B2 is concentration dependent and that it involves the packing of hydrophobic residues normally exposed on the surface of kalata B2 into a multimeric hydrophobic core. Interestingly, the hydrophobic surface that is "quenched" has previously been shown to be responsible for the ability of kalata B2 to insert into membranes. Thus, it seems unlikely that the oligomers observed in aqueous solution are related to any multimeric state present in a membrane environment, and responsible for the formation of pores. The ability to self-associate might alternatively provide a mechanism for preventing self-toxicity when stored at high concentrations in intracellular compartments.
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Affiliation(s)
- K Johan Rosengren
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia; Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
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61
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Poth AG, Chan LY, Craik DJ. Cyclotides as grafting frameworks for protein engineering and drug design applications. Biopolymers 2016; 100:480-91. [PMID: 23893608 DOI: 10.1002/bip.22284] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 04/30/2013] [Accepted: 05/07/2013] [Indexed: 11/08/2022]
Abstract
Cyclotides are a family of naturally occurring backbone-cyclized macrocyclic mini-proteins from plants that have a knotted trio of intramolecular disulfide bonds. Their structural features imbue cyclotides with extraordinary stability against degradation at elevated temperatures or in the presence of proteolytic enzymes. The plasticity of their intracysteine loop sequences is exemplified by the more than 250 natural cyclotides sequenced to date, and this tolerance to sequence variation, along with their diverse bioactivities, underpins the suitability of the cyclic cystine knot motif as a valuable drug design scaffold and research tool for protein engineering studies. Here, we review the recent literature on applications of cyclotides for the stabilization of peptide epitopes and related protein engineering studies. Possible future directions in this field are also described.
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Affiliation(s)
- Aaron G Poth
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, 4072, Australia
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62
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Gilding EK, Jackson MA, Poth AG, Henriques ST, Prentis PJ, Mahatmanto T, Craik DJ. Gene coevolution and regulation lock cyclic plant defence peptides to their targets. THE NEW PHYTOLOGIST 2016; 210:717-30. [PMID: 26668107 DOI: 10.1111/nph.13789] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 10/28/2015] [Indexed: 05/20/2023]
Abstract
Plants have evolved many strategies to protect themselves from attack, including peptide toxins that are ribosomally synthesized and thus adaptable directly by genetic polymorphisms. Certain toxins in Clitoria ternatea (butterfly pea) are cyclic cystine-knot peptides of c. 30 residues, called cyclotides, which have co-opted the plant's albumin-1 gene family for their production. How butterfly pea albumin-1 genes were commandeered and how these cyclotides are utilized in defence remain unclear. The role of cyclotides in host plant ecology and biotechnological applications requires exploration. We characterized the sequence diversity and expression dynamics of precursor and processing proteins implicated in butterfly pea cyclotide biosynthesis by expression profiling through RNA-sequencing (RNA-seq). Peptide-enriched extracts from various organs were tested for activity against insect-like membranes and the model nematode Caenorhabditis elegans. We found that the evolution and deployment of cyclotides involved their diversification to exhibit different chemical properties and expression between organs facing different defensive challenges. Cyclotide-enriched fractions from soil-contacting organs were effective at killing nematodes, whereas similar enriched fractions from aerial organs contained cyclotides that exhibited stronger interactions with insect-like membrane lipids. Cyclotides are employed as versatile and combinatorial mediators of defence in C. ternatea and have specialized to affect different classes of attacking organisms.
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Affiliation(s)
- Edward K Gilding
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - Mark A Jackson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - Aaron G Poth
- 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
| | - Peter J Prentis
- Earth, Environment, and Biological Sciences, Queensland University of Technology, Brisbane, Qld, 4000, Australia
| | - Tunjung Mahatmanto
- 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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63
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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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Synthetic Cystine-Knot Miniproteins - Valuable Scaffolds for Polypeptide Engineering. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 917:121-44. [PMID: 27236555 DOI: 10.1007/978-3-319-32805-8_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Peptides with the cystine-knot architecture, often termed knottins, are promising scaffolds for biomolecular engineering. These unique molecules combine diverse bioactivities with excellent structural, thermal, and proteolytical stability. Being different in the composition and structure of their amino acid backbone, knottins share the same core element, namely cystine knot, which is built by six cysteine residues forming three disulfides upon oxidative folding. This motif ensures a notably rigid framework that highly tolerates both rational and combinatorial changes in the primary structure. Being accessible through recombinant production and total chemical synthesis, cystine-knot miniproteins can be endowed with novel bioactivities by variation of surface-exposed loops and incorporation of non-natural elements within their non-conserved regions towards the generation of tailor-made peptidic compounds. In this chapter the topology of cystine-knot peptides, their synthesis and applications for diagnostics and therapy is discussed.
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Farhadpour M, Hashempour H, Talebpour Z, A-Bagheri N, Shushtarian MS, Gruber CW, Ghassempour A. Microwave-assisted extraction of cyclotides from Viola ignobilis. Anal Biochem 2015; 497:83-9. [PMID: 26706804 DOI: 10.1016/j.ab.2015.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 11/10/2015] [Accepted: 12/03/2015] [Indexed: 01/15/2023]
Abstract
Cyclotides are an interesting family of circular plant peptides. Their unique three-dimensional structure, comprising a head-to-tail circular backbone chain and three disulfide bonds, confers them stability against thermal, chemical, and enzymatic degradation. Their unique stability under extreme conditions creates an idea about the possibility of using harsh extraction methods such as microwave-assisted extraction (MAE) without affecting their structures. MAE has been introduced as a potent extraction method for extraction of natural compounds, but it is seldom used for peptide and protein extraction. In this work, microwave irradiation was applied to the extraction of cyclotides. The procedure was performed in various steps using a microwave instrument under different conditions. High-performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) results show stability of cyclotide structures on microwave radiation. The influential parameters, including time, temperature, and the ratio of solvents that are affecting the MAE potency, were optimized. Optimal conditions were obtained at 20 min of irradiation time, 1200 W of system power in 60 °C, and methanol/water at the ratio of 90:10 (v/v) as solvent. The comparison of MAE results with maceration extraction shows that there are similarities between cyclotide sequences and extraction yields.
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Affiliation(s)
- Mohsen Farhadpour
- Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Evin, Tehran, Iran
| | - Hossein Hashempour
- Department of Chemistry, Faculty of Basic Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran
| | - Zahra Talebpour
- Department of Chemistry, Alzahra University, Vanac, Tehran, Iran
| | - Nazanin A-Bagheri
- Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Evin, Tehran, Iran
| | | | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Alireza Ghassempour
- Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Evin, Tehran, Iran.
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66
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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: 30] [Impact Index Per Article: 3.3] [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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67
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Sangphukieo A, Nawae W, Laomettachit T, Supasitthimethee U, Ruengjitchatchawalya M. Computational Design of Hypothetical New Peptides Based on a Cyclotide Scaffold as HIV gp120 Inhibitor. PLoS One 2015; 10:e0139562. [PMID: 26517259 PMCID: PMC4627658 DOI: 10.1371/journal.pone.0139562] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 09/15/2015] [Indexed: 11/19/2022] Open
Abstract
Cyclotides are a family of triple disulfide cyclic peptides with exceptional resistance to thermal/chemical denaturation and enzymatic degradation. Several cyclotides have been shown to possess anti-HIV activity, including kalata B1 (KB1). However, the use of cyclotides as anti-HIV therapies remains limited due to the high toxicity in normal cells. Therefore, grafting anti-HIV epitopes onto a cyclotide might be a promising approach for reducing toxicity and simultaneously improving anti-HIV activity. Viral envelope glycoprotein gp120 is required for entry of HIV into CD4+ T cells. However, due to a high degree of variability and physical shielding, the design of drugs targeting gp120 remains challenging. We created a computational protocol in which molecular modeling techniques were combined with a genetic algorithm (GA) to automate the design of new cyclotides with improved binding to HIV gp120. We found that the group of modified cyclotides has better binding scores (23.1%) compared to the KB1. By using molecular dynamic (MD) simulation as a post filter for the final candidates, we identified two novel cyclotides, GA763 and GA190, which exhibited better interaction energies (36.6% and 22.8%, respectively) when binding to gp120 compared to KB1. This computational design represents an alternative tool for modifying peptides, including cyclotides and other stable peptides, as therapeutic agents before the synthesis process.
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Affiliation(s)
- Apiwat Sangphukieo
- Bioinformatics and Systems Biology program, King Mongkut’s University of Technology Thonburi (KMUTT), Bang Khun Thian, Bangkok, 10150, Thailand
| | - Wanapinun Nawae
- Pilot Plant Development and Training Institute, KMUTT (Bang Khun Thian), Bangkok, 10150, Thailand
| | - Teeraphan Laomettachit
- Bioinformatics and Systems Biology program, King Mongkut’s University of Technology Thonburi (KMUTT), Bang Khun Thian, Bangkok, 10150, Thailand
| | | | - Marasri Ruengjitchatchawalya
- Bioinformatics and Systems Biology program, King Mongkut’s University of Technology Thonburi (KMUTT), Bang Khun Thian, Bangkok, 10150, Thailand
- Biotechnology program, School of Bioresources and Technology, KMUTT (Bang Khun Thian), Bangkok, 10150, Thailand
- * E-mail:
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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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Zhang J, Hua Z, Huang Z, Chen Q, Long Q, Craik DJ, Baker AJM, Shu W, Liao B. Two Blast-independent tools, CyPerl and CyExcel, for harvesting hundreds of novel cyclotides and analogues from plant genomes and protein databases. PLANTA 2015; 241:929-940. [PMID: 25528148 DOI: 10.1007/s00425-014-2229-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 12/10/2014] [Indexed: 06/04/2023]
Abstract
Two high-throughput tools harvest hundreds of novel cyclotides and analogues in plants. Cyclotides are gene-encoded backbone-cyclized polypeptides displaying a diverse range of bioactivities associated with plant defense. However, genome-scale or database-scale evaluations of cyclotides have been rare so far. Here, a novel time-efficient Perl program, CyPerl, was developed for searching cyclotides from predicted ORFs of 34 available plant genomes and existing plant protein sequences from Genbank databases. CyPerl-isolated sequences were further analyzed by removing repeats, evaluating their cysteine-distributed regions (CDRs) and comparing with CyBase-collected cyclotides in a user-friendly Excel (Microsoft Office) template, CyExcel. After genome-screening, 186 ORFs containing 145 unique cyclotide analogues were identified by CyPerl and CyExcel from 30 plant genomes tested from 10 plant families. Phaseolus vulgaris and Zea mays were the richest two species containing cyclotide analogues in the plants tested. After screening protein databases, 266 unique cyclotides and analogues were identified from seven plant families. By merging with 288 unique CyBase-listed cyclotides, 510 unique cyclotides and analogues were obtained from 13 plant families. In total, seven novel plant families containing cyclotide analogues and 202 novel cyclotide analogues were identified in this study. This study has established two Blast-independent tools for screening cyclotides from plant genomes and protein databases, and has also significantly widened the plant distribution and sequence diversity of cyclotides and their analogues.
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Affiliation(s)
- Jun Zhang
- School of Biosciences and Biopharmaceutics, Guangdong Province Key Laboratory for Biotechnology Drug Candidates, Guangdong Pharmaceutical University, Guangzhou, 510006, China,
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70
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Tarasava K, Freisinger E. An optimized intein-mediated protein ligation approach for the efficient cyclization of cysteine-rich proteins. Protein Eng Des Sel 2014; 27:481-8. [PMID: 25335928 DOI: 10.1093/protein/gzu048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Head-to-tail backbone cyclization of proteins is a widely used approach for the improvement of protein stability. One way to obtain cyclic proteins via recombinant expression makes use of engineered Intein tags, which are self-cleaving protein domains. In this approach, pH-induced self-cleavage of the N-terminal Intein tag generates an N-terminal cysteine residue at the target protein, which then attacks in an intramolecular reaction the C-terminal thioester formed by the second C-terminal Intein tag resulting in the release of the cyclic target protein. In the current work we aimed to produce a cyclic analog of the small γ-Ec-1 domain of the wheat metallothionein, which contains six cysteine residues. During the purification process we faced several challenges, among them premature cleavage of one or the other Intein tag resulting in decreasing yields and contamination with linear species. To improve efficiency of the system we applied a number of optimizations such as the introduction of a Tobacco etch virus cleavage site and an additional poly-histidine tag. Our efforts resulted in the production of a cyclic protein in moderate yields without any contamination with linear protein species.
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Affiliation(s)
- Katsiaryna Tarasava
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Eva Freisinger
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
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71
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Cyclotide structure-activity relationships: qualitative and quantitative approaches linking cytotoxic and anthelmintic activity to the clustering of physicochemical forces. PLoS One 2014; 9:e91430. [PMID: 24682019 PMCID: PMC3969350 DOI: 10.1371/journal.pone.0091430] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 02/11/2014] [Indexed: 11/19/2022] Open
Abstract
Cyclotides are a family of plant-derived proteins that are characterized by a cyclic backbone and a knotted disulfide topology. Their cyclic cystine knot (CCK) motif makes them exceptionally resistant to thermal, chemical, and enzymatic degradation. Cyclotides exert much of their biological activity via interactions with cell membranes. In this work, we qualitatively and quantitatively analyze the cytotoxic and anthelmintic membrane activities of cyclotides. The qualitative and quantitative models describe the potency of cyclotides using four simple physicochemical terms relevant to membrane contact. Specifically, surface areas of the cyclotides representing lipophilic and hydrogen bond donating properties were quantified and their distribution across the molecular surface was determined. The resulting quantitative structure-activity relation (QSAR) models suggest that the activity of the cyclotides is proportional to their lipophilic and positively charged surface areas, provided that the distribution of these surfaces is asymmetric. In addition, we qualitatively analyzed the physicochemical differences between the various cyclotide subfamilies and their effects on the cyclotides' orientation on the membrane and membrane activity.
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72
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Burman R, Gunasekera S, Strömstedt AA, Göransson U. Chemistry and biology of cyclotides: circular plant peptides outside the box. JOURNAL OF NATURAL PRODUCTS 2014; 77:724-36. [PMID: 24527877 DOI: 10.1021/np401055j] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Cyclotides stand out as the largest family of circular proteins of plant origin hitherto known, with more than 280 sequences isolated at peptide level and many more predicted from gene sequences. Their unusual stability resulting from the signature cyclic cystine knot (CCK) motif has triggered a broad interest in these molecules for potential therapeutic and agricultural applications. Since the time of the first cyclotide discovery, our laboratory in Uppsala has been engaged in cyclotide discovery as well as the development of protocols to isolate and characterize these seamless peptides. We have also developed methods to chemically synthesize cyclotides by Fmoc-SPPS, which are useful in protein grafting applications. In this review, experience in cyclotide research over two decades and the recent literature related to their structures, synthesis, and folding as well the recent proof-of-concept findings on their use as "epitope" stabilizing scaffolds are summarized.
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Affiliation(s)
- Robert Burman
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala University , Biomedical Centre, Box 574, SE-751 23 Uppsala, Sweden
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73
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Mahatmanto T, Poth AG, Mylne JS, Craik DJ. A comparative study of extraction methods reveals preferred solvents for cystine knot peptide isolation from Momordica cochinchinensis seeds. Fitoterapia 2014; 95:22-33. [PMID: 24613804 DOI: 10.1016/j.fitote.2014.02.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 02/21/2014] [Accepted: 02/25/2014] [Indexed: 11/16/2022]
Abstract
MCoTI-I and MCoTI-II (short for Momordica cochinchinensis Trypsin Inhibitor-I and -II, respectively) are attractive candidates for developing novel intracellular-targeting drugs because both are exceptionally stable and can internalize into cells. These seed-derived cystine knot peptides are examples of how natural product discovery efforts can lead to biomedical applications. However, discovery efforts are sometimes hampered by the limited availability of seed materials, highlighting the need for efficient extraction methods. In this study, we assessed five extraction methods using M. cochinchinensis seeds, a source of well-characterized cystine knot peptides. The most efficient extraction of nine known cystine knot peptides was achieved by a method based on acetonitrile/water/formic acid (25:24:1), followed by methods based on sodium acetate (20 mM, pH 5.0), ammonium bicarbonate (5 mM, pH 8.0), and boiling water. On average, the yields obtained by these four methods were more than 250-fold higher than that obtained using dichloromethane/methanol (1:1) extraction, a previously applied standard method. Extraction using acetonitrile/water/formic acid (25:24:1) yielded the highest number of reconstructed masses within the majority of plant-derived cystine knot peptide mass range but only accounted for around 50% of the total number of masses, indicating that any single method may result in under-sampling. Applying acetonitrile/water/formic acid (25:24:1), boiling water, and ammonium bicarbonate (5 mM, pH 8.0) extractions either successively or discretely significantly increased the sampling number. Overall, acetonitrile/water/formic acid (25:24:1) can facilitate efficient extraction of cystine-knot peptides from M. cochinchinensis seeds but for discovery purposes the use of a combination of extraction methods is recommended where practical.
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Affiliation(s)
- Tunjung Mahatmanto
- 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.
| | - Joshua S Mylne
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia; School of Chemistry and Biochemistry & ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Perth, Western Australia 6009, Australia.
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.
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74
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Jia X, Kwon S, Wang CIA, Huang YH, Chan LY, Tan CC, Rosengren KJ, Mulvenna JP, Schroeder CI, Craik DJ. Semienzymatic cyclization of disulfide-rich peptides using Sortase A. J Biol Chem 2014; 289:6627-6638. [PMID: 24425873 DOI: 10.1074/jbc.m113.539262] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Disulfide-rich cyclic peptides have generated great interest in the development of peptide-based therapeutics due to their exceptional stability toward chemical, enzymatic, or thermal attack. In particular, they have been used as scaffolds onto which bioactive epitopes can be grafted to take advantage of the favorable biophysical properties of disulfide-rich cyclic peptides. To date, the most commonly used method for the head-to-tail cyclization of peptides has been native chemical ligation. In recent years, however, enzyme-mediated cyclization has become a promising new technology due to its efficiency, safety, and cost-effectiveness. Sortase A (SrtA) is a bacterial enzyme with transpeptidase activity. It recognizes a C-terminal penta-amino acid motif, LPXTG, and cleaves the amide bond between Thr and Gly to form a thioacyl-linked intermediate. This intermediate undergoes nucleophilic attack by an N-terminal poly-Gly sequence to form an amide bond between the Thr and N-terminal Gly. Here, we demonstrate that sortase A can successfully be used to cyclize a variety of small disulfide-rich peptides, including the cyclotide kalata B1, α-conotoxin Vc1.1, and sunflower trypsin inhibitor 1. These peptides range in size from 14 to 29 amino acids and contain three, two, or one disulfide bond, respectively, within their head-to-tail cyclic backbones. Our findings provide proof of concept for the potential broad applicability of enzymatic cyclization of disulfide-rich peptides with therapeutic potential.
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Affiliation(s)
- Xinying Jia
- From QIMR Berghofer Medical Research, Brisbane 4000, Queensland, Australia; Institute for Molecular Bioscience, University of Queensland, Brisbane 4072, Queensland, Australia
| | - Soohyun Kwon
- Institute for Molecular Bioscience, University of Queensland, Brisbane 4072, Queensland, Australia
| | - Ching-I Anderson Wang
- Institute for Molecular Bioscience, University of Queensland, Brisbane 4072, Queensland, Australia
| | - Yen-Hua Huang
- Institute for Molecular Bioscience, University of Queensland, Brisbane 4072, Queensland, Australia
| | - Lai Y Chan
- Institute for Molecular Bioscience, University of Queensland, Brisbane 4072, Queensland, Australia
| | - Chia Chia Tan
- Institute for Molecular Bioscience, University of Queensland, Brisbane 4072, Queensland, Australia
| | - K Johan Rosengren
- School of Biomedical Sciences, University of Queensland, Brisbane 4072, Queensland, Australia
| | - Jason P Mulvenna
- From QIMR Berghofer Medical Research, Brisbane 4000, Queensland, Australia
| | - Christina I Schroeder
- Institute for Molecular Bioscience, University of Queensland, Brisbane 4072, Queensland, Australia.
| | - David J Craik
- Institute for Molecular Bioscience, University of Queensland, Brisbane 4072, Queensland, Australia.
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75
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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: 220] [Impact Index Per Article: 20.0] [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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76
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Gerlach SL, Yeshak M, Göransson U, Roy U, Izadpanah R, Mondal D. Cycloviolacin O2 (CyO2) suppresses productive infection and augments the antiviral efficacy of nelfinavir in HIV-1 infected monocytic cells. Biopolymers 2013; 100:471-9. [DOI: 10.1002/bip.22325] [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: 04/02/2013] [Accepted: 05/28/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Samantha L. Gerlach
- Department of Pharmacology; Tulane University Health Sciences Center; 1430 Tulane Avenue New Orleans LA 70112
| | - Mariamawit Yeshak
- Division of Pharmacognosy; Department of Medicinal Chemistry, Uppsala University, Biomedical Centre; 574 S-751 23 Uppsala Sweden
| | - Ulf Göransson
- Division of Pharmacognosy; Department of Medicinal Chemistry, Uppsala University, Biomedical Centre; 574 S-751 23 Uppsala Sweden
| | - Upal Roy
- Department of Immunology; Florida International University; 11200 SW 8 Street AHC2 Miami FL 33199
| | - Reza Izadpanah
- Heart and Vascular Institute; Tulane University Health Sciences Center; 1430 Tulane Avenue New Orleans LA 70112
| | - Debasis Mondal
- Department of Pharmacology; Tulane University Health Sciences Center; 1430 Tulane Avenue New Orleans LA 70112
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77
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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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78
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Solution NMR studies on the orientation of membrane-bound peptides and proteins by paramagnetic probes. Molecules 2013; 18:7407-35. [PMID: 23799448 PMCID: PMC6269851 DOI: 10.3390/molecules18077407] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 06/13/2013] [Accepted: 06/20/2013] [Indexed: 12/24/2022] Open
Abstract
Many peptides and proteins are attached to or immersed in a biological membrane. In order to understand their function not only the structure but also their topology in the membrane is important. Solution NMR spectroscopy is one of the most often used approaches to determine the orientation and localization of membrane-bound peptides and proteins. Here we give an application-oriented overview on the use of paramagnetic probes for the investigation of membrane-bound peptides and proteins. The examples discussed range from the large pool of antimicrobial peptides, bacterial toxins, cell penetrating peptides to domains of larger proteins or the calcium regulating protein phospholamban. Topological information is obtained in all these examples by the use of either attached or freely mobile paramagnetic tags. For some examples information obtained from the paramagnetic probes was included in the structure determination.
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79
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Gassericin A: a circular bacteriocin produced by Lactic acid bacteria Lactobacillus gasseri. World J Microbiol Biotechnol 2013; 29:1977-87. [DOI: 10.1007/s11274-013-1368-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/03/2013] [Indexed: 10/26/2022]
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80
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Kaas Q, Craik DJ. NMR of plant proteins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 71:1-34. [PMID: 23611313 DOI: 10.1016/j.pnmrs.2013.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 01/21/2013] [Indexed: 06/02/2023]
Affiliation(s)
- Quentin Kaas
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland 4072, Australia
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81
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Nguyen GKT, Lian Y, Pang EWH, Nguyen PQT, Tran TD, Tam JP. Discovery of linear cyclotides in monocot plant Panicum laxum of Poaceae family provides new insights into evolution and distribution of cyclotides in plants. J Biol Chem 2012. [PMID: 23195955 DOI: 10.1074/jbc.m112.415356] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclotides are disulfide-rich macrocyclic peptides that display a wide range of bioactivities and represent an important group of plant defense peptide biologics. A few linear variants of cyclotides have recently been identified. They share a high sequence homology with cyclotides but are biosynthetically unable to cyclize from their precursors. All hitherto reported cyclotides and their acyclic variants were isolated from dicot plants of the Rubiaceae, Violaceae, Cucurbitaceae, and recently the Fabaceae and Solanaceae families. Although several cyclotide-like genes in the Poaceae family were known from the data mining of the National Center for Biotechnology Information (NCBI) nucleotide database, their expression at the protein level has yet to be proven. Here, we report the discovery and characterization of nine novel linear cyclotides, designated as panitides L1-9, from the Panicum laxum of the Poaceae family and provide the first evidence of linear cyclotides at the protein level in a monocot plant. Disulfide mapping of panitide L3 showed that it possesses a cystine knot arrangement similar to cyclotides. Several panitides were shown to be active against Escherichia coli and cytotoxic to HeLa cells. They also displayed a high stability against heat and proteolytic degradation. Oxidative folding of the disulfide-reduced panitide L1 showed that it can fold efficiently into its native form. The presence of linear cyclotides in both dicots and monocots suggests their ancient origin and existence before the divergence of these two groups of flowering plants. Moreover, the Poaceae family contains many important food crops, and our discovery may open up new avenues of research using cyclotides and their acyclic variants in crop protection.
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82
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Chemical synthesis, backbone cyclization and oxidative folding of cystine-knot peptides: promising scaffolds for applications in drug design. Molecules 2012; 17:12533-52. [PMID: 23095896 PMCID: PMC6268209 DOI: 10.3390/molecules171112533] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 09/19/2012] [Accepted: 10/22/2012] [Indexed: 02/03/2023] Open
Abstract
Cystine-knot peptides display exceptional structural, thermal, and biological stability. Their eponymous motif consists of six cysteine residues that form three disulfide bonds, resulting in a notably rigid structural core. Since they highly tolerate either rational or combinatorial changes in their primary structure, cystine knots are considered to be promising frameworks for the development of peptide-based pharmaceuticals. Despite their relatively small size (two to three dozens amino acid residues), the chemical synthesis route is challenging since it involves critical steps such as head-to-tail cyclization and oxidative folding towards the respective bioactive isomer. Herein we describe the topology of cystine-knot peptides, their synthetic availability and briefly discuss potential applications of engineered variants in diagnostics and therapy.
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83
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Eliasen R, Daly NL, Wulff BS, Andresen TL, Conde-Frieboes KW, Craik DJ. Design, synthesis, structural and functional characterization of novel melanocortin agonists based on the cyclotide kalata B1. J Biol Chem 2012; 287:40493-501. [PMID: 23012369 DOI: 10.1074/jbc.m112.395442] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Cyclotides are useful scaffolds to stabilize bioactive peptides. RESULTS Four melanocortin analogues of kalata B1 were synthesized. One is a selective MC4R agonist. CONCLUSION The analogues retain the native kalata B1 scaffold and introduce a designed pharmacological activity, validating cyclotides as protein engineering scaffolds. SIGNIFICANCE A novel type of melanocortin agonist has been developed, with potential as a drug lead for treating obesity. Obesity is an increasingly important global health problem that lacks current treatment options. The melanocortin receptor 4 (MC4R) is a target for obesity therapies because its activation triggers appetite suppression and increases energy expenditure. Cyclotides have been suggested as scaffolds for the insertion and stabilization of pharmaceutically active peptides. In this study, we explored the development of appetite-reducing peptides by synthesizing MC4R agonists based on the insertion of the His-Phe-Arg-Trp sequence into the cyclotide kalata B1. The ability of the analogues to fold similarly to kalata B1 but display MC4R activity were investigated. Four peptides were synthesized using t-butoxycarbonyl peptide chemistry with a C-terminal thioester to facilitate backbone cyclization. The structures of the peptides were found to be similar to kalata B1, evaluated by Hα NMR chemical shifts. KB1(GHFRWG;23-28) had a K(i) of 29 nm at the MC4R and was 107 or 314 times more selective over this receptor than MC1R or MC5R, respectively, and had no detectable binding to MC3R. The peptide had higher affinity for the MC4R than the endogenous agonist, α-melanocyte stimulation hormone, but it was less potent at the MC4R, with an EC(50) of 580 nm for activation of the MC4R. In conclusion, we synthesized melanocortin analogues of kalata B1 that preserve the structural scaffold and display receptor binding and functional activity. KB1(GHFRWG;23-28) is potent and selective for the MC4R. This compound validates the use of cyclotides as scaffolds and has the potential to be a new lead for the treatment of obesity.
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84
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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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85
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Gly6 of kalata B1 is critical for the selective binding to phosphatidylethanolamine membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2354-61. [DOI: 10.1016/j.bbamem.2012.04.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 03/29/2012] [Accepted: 04/10/2012] [Indexed: 11/18/2022]
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86
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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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87
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88
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Poth AG, Mylne JS, Grassl J, Lyons RE, Millar AH, Colgrave ML, Craik DJ. Cyclotides associate with leaf vasculature and are the products of a novel precursor in petunia (Solanaceae). J Biol Chem 2012; 287:27033-46. [PMID: 22700981 DOI: 10.1074/jbc.m112.370841] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclotides are a large family of plant peptides that are structurally defined by their cyclic backbone and a trifecta of disulfide bonds, collectively known as the cyclic cystine knot (CCK) motif. Structurally similar cyclotides have been isolated from plants within the Rubiaceae, Violaceae, and Fabaceae families and share the CCK motif with trypsin-inhibitory knottins from a plant in the Cucurbitaceae family. Cyclotides have previously been reported to be encoded by dedicated genes or as a domain within a knottin-encoding PA1-albumin-like gene. Here we report the discovery of cyclotides and related non-cyclic peptides we called "acyclotides" from petunia of the agronomically important Solanaceae plant family. Transcripts for petunia cyclotides and acyclotides encode the shortest known cyclotide precursors. Despite having a different precursor structure, their sequences suggest that petunia cyclotides mature via the same biosynthetic route as other cyclotides. We assessed the spatial distribution of cyclotides within a petunia leaf section by MALDI imaging and observed that the major cyclotide component Phyb A was non-uniformly distributed. Dissected leaf midvein extracts contained significantly higher concentrations of this cyclotide compared with the lamina and outer margins of leaves. This is the third distinct type of cyclotide precursor, and Solanaceae is the fourth phylogenetically disparate plant family to produce these structurally conserved cyclopeptides, suggesting either convergent evolution upon the CCK structure or movement of cyclotide-encoding sequences within the plant kingdom.
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Affiliation(s)
- Aaron G Poth
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
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89
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Choi SJ, Jeong WJ, Kang SK, Lee M, Kim E, Ryu DY, Lim YB. Differential Self-Assembly Behaviors of Cyclic and Linear Peptides. Biomacromolecules 2012; 13:1991-5. [DOI: 10.1021/bm3005947] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Sung-ju Choi
- Translational Research Center for Protein Function Control and Department of Materials Science & Engineering and§Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 120-749, Korea
| | - Woo-jin Jeong
- Translational Research Center for Protein Function Control and Department of Materials Science & Engineering and§Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 120-749, Korea
| | - Seong-Kyun Kang
- Center for Bio-Responsive Assembly
and Department of Chemistry, Seoul National University, Seoul 151-747, Korea
| | - Myongsoo Lee
- Center for Bio-Responsive Assembly
and Department of Chemistry, Seoul National University, Seoul 151-747, Korea
| | | | | | - Yong-beom Lim
- Translational Research Center for Protein Function Control and Department of Materials Science & Engineering and§Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 120-749, Korea
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90
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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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91
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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: 61] [Impact Index Per Article: 5.1] [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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92
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Craik DJ, Swedberg JE, Mylne JS, Cemazar M. Cyclotides as a basis for drug design. Expert Opin Drug Discov 2012; 7:179-94. [PMID: 22468950 DOI: 10.1517/17460441.2012.661554] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Cyclotides are plant-made defence proteins with a head-to-tail cyclic backbone combined with a conserved, six cystine knot. They have a range of biological activities, including uterotonic and anti-HIV activity, which have attracted attention to their potential pharmaceutical applications. Furthermore, their unique structures and high stability make them appealing as peptide-based templates for drug design applications. Methods have been developed for their production, including solid phase peptide synthesis as well as recombinant methods. AREAS COVERED This article reviews the recent literature associated with therapeutic applications of naturally occurring and synthetically modified cyclotides. It includes applications of cyclotides and cyclotide-like molecules as peptide-based drug leads and diagnostic agents. EXPERT OPINION The ultra-stable cyclotides are promising templates for drug development applications and are currently being assessed for the potential breadth of their applications. For synthetic versions of cyclotides to enter human clinical trials further studies to examine their biopharmaceutical properties and toxicities are required. However, several promising proof-of-concept studies have established that pharmaceutically relevant bioactive peptide sequences can be grafted into cyclotide frameworks and thereby stabilised, while maintaining biological activity. These studies include examples directed at cancer, cardiovascular disease and infectious diseases. Solid phase peptide synthesis has been the preferred approach for making pharmaceutically modified cyclotides so far, but promising progress is being made in biological approaches to cyclotide production.
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Affiliation(s)
- David J Craik
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Australia.
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93
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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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94
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Romuald C, Coutrot F. Combining coordination chemistry and catalysis to tie a knot by an active-metal template strategy. Angew Chem Int Ed Engl 2012; 51:2544-5. [PMID: 22238238 DOI: 10.1002/anie.201107112] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Indexed: 11/07/2022]
Abstract
Collar and tie men: the smallest trefoil knot reported to date has been prepared by an active metal template synthesis. Copper(I) ions are able to constrain the well-designed structure so that it can form the loops by complexing to the bipyridine moieties in the core of the thread and the two ends of the entangled lace on opposite faces of the loop, before acting as a catalyst to close the lace.
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Affiliation(s)
- Camille Romuald
- Institut des Biomolécules Max Mousseron -UMR CNRS Supramolecular Machines and ARchitectures Team, Universités Montpellier, Bâtiment de Recherche Max Mousseron, Ecole Nationale Supérieure de Chimie de Montpellier, France
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95
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Romuald C, Coutrot F. Bildung von Knoten mithilfe aktiver Metalltemplate: Zusammenspiel von Koordinationschemie und Katalyse. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201107112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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96
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Bowers AA. Biochemical and biosynthetic preparation of natural product-like cyclic peptide libraries. MEDCHEMCOMM 2012. [DOI: 10.1039/c2md20068f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Natural product gene clusters are increasingly being used to compliment biochemical methods for production of cyclic peptide libraries.
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Affiliation(s)
- Albert A. Bowers
- Purdue University
- Dept. of Medicinal Chemistry and Molecular Pharmacology
- West Lafayette
- USA
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97
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Romuald C, Ardá A, Clavel C, Jiménez-Barbero J, Coutrot F. Tightening or loosening a pH-sensitive double-lasso molecular machine readily synthesized from an ends-activated [c2]daisy chain. Chem Sci 2012. [DOI: 10.1039/c2sc20072d] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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98
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Sagar S, Gehring C, Minneman KP. Methods to Isolate and Identify New Plant Signaling Peptides. SIGNALING AND COMMUNICATION IN PLANTS 2012. [DOI: 10.1007/978-3-642-27603-3_12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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99
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100
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Conlan BF, Gillon AD, Barbeta BL, Anderson MA. Subcellular targeting and biosynthesis of cyclotides in plant cells. AMERICAN JOURNAL OF BOTANY 2011; 98:2018-26. [PMID: 22081413 DOI: 10.3732/ajb.1100382] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
PREMISE OF THE STUDY The cyclotide kalata B1 is found in the leaves of Oldenlandia affinis and is a potent insecticidal and nematocidal molecule. This peptide is cleaved from a precursor protein, Oak1, and ligation of the N- and C-termini occurs to form a continuous peptide backbone. The subcellular location of the excision and cyclization reactions is unknown, and there is debate as to which enzyme catalyzes the event. To determine where in the plant cell Oak1 is processed, we prepared constructs encoding GFP (green fluorescent protein) linked to the cyclotide precursor Oak1. METHODS The GFP constructs were transiently expressed in the leaves of Nicotiana benthamiana, and GFP fluorescence was observed in living cells using confocal microscopy. A Fei Mao (FM) styryl dye was infiltrated into whole leaves that were still growing and expressing GFP constructs, enabling the plasma membrane and the tonoplast to be highlighted for visualization of the vacuole in living cells. KEY RESULTS The full length Oak1 precursor directed GFP to the vacuole, suggesting that excision and cyclization of the cyclotide domain occurs in the vacuole where the cyclotides are then stored. The N-terminal propeptide and N-terminal repeat of Oak1 were both sufficient to target GFP to the vacuole, although the C-terminal propeptide, which is essential for cyclization, was not a targeting signal. CONCLUSIONS The vacuolar location of cyclotides supports our hypothesis that the vacuolar processing enzyme, asparaginyl endoproteinase, has a pivotal role in excision and cyclization from cyclotide precursors.
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Affiliation(s)
- Brendon F Conlan
- Department of Biochemistry, La Trobe University, Melbourne, Victoria, Australia
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