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Batiha GES, Lukman HY, Shaheen HM, Wasef L, Hafiz AA, Conte-Junior CA, Al-Farga A, Chamba MVM, Lawal B. A Systematic Review of Phytochemistry, Nutritional Composition, and Pharmacologic Application of Species of the Genus Viola in Noncommunicable Diseases (NCDs). EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2023; 2023:5406039. [PMID: 37941895 PMCID: PMC10630019 DOI: 10.1155/2023/5406039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 06/03/2023] [Accepted: 10/11/2023] [Indexed: 11/10/2023]
Abstract
Viola L. is the largest genus of the Violaceae family with more than 500 species across the globe. The present extensive literature survey revealed Viola species to be a group of important nutritional and medicinal plants used for the ethnomedicinal treatment of noncommunicable diseases (NCDs) such as diabetes, asthma, lung diseases, and fatigue. Many plant species of this genus have also received scientific validation of their pharmacological activities including neuroprotective, immunomodulatory, anticancer, antihypertensive, antidyslipidemic, analgesic, antipyretic, diuretic, anti-inflammatory, anthelmintic, and antioxidant. Viola is highly rich in different natural products some of which have been isolated and identified in the past few decades; these include flavonoids terpenoids and phenylpropanoids of different pharmacological activities. The pharmacokinetics and clinical studies on this genus are lacking, and the present review is aimed at summarizing the current understanding of the ethnopharmacology, phytochemistry, nutritional composition, and pharmacological profile of medicinal plants from the Viola genus to reveal its therapeutic potentials, gaps, and subsequently open a new window for future pharmacological research.
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Affiliation(s)
- Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22511, AlBeheira, Egypt
| | - Halimat Yusuf Lukman
- Department of Chemical Sciences, Biochemistry Unit, College of Natural and Applied Sciences, Summit University Offa, Offa PMB 4412, Nigeria
| | - Hazem M. Shaheen
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22511, AlBeheira, Egypt
| | - Lamiaa Wasef
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22511, AlBeheira, Egypt
| | - Amin A. Hafiz
- Department of Clinical Nutrition, Faculty of Applied Medical Sciences, Umm Al-Qura University, Mecca, Saudi Arabia
| | - Carlos Adam Conte-Junior
- Laboratory of Advanced Analysis in Biochemistry and Molecular Biology (LAABBM), Department of Biochemistry, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro RJ 21941-909, Brazil
| | - Ammar Al-Farga
- Biochemistry Department, Faculty of Science, University of Jeddah, Jeddah 21577, Saudi Arabia
| | - Moses V. M. Chamba
- Department of Physics and Biochemical Sciences, Malawi University of Business and Applied Sciences, Private Bag 303, Chichiri, Blantyre 3, Malawi
| | - Bashir Lawal
- Faculty of Medical Science, New Gate University, Minna, Nigeria
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2
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Sahu N, Khire SS, Gadre SR. Combining fragmentation method and high-performance computing: Geometry optimization and vibrational spectra of proteins. J Chem Phys 2023; 159:044309. [PMID: 37522406 DOI: 10.1063/5.0149572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 07/12/2023] [Indexed: 08/01/2023] Open
Abstract
Exploring the structures and spectral features of proteins with advanced quantum chemical methods is an uphill task. In this work, a fragment-based molecular tailoring approach (MTA) is appraised for the CAM-B3LYP/aug-cc-pVDZ-level geometry optimization and vibrational infrared (IR) spectra calculation of ten real proteins containing up to 407 atoms and 6617 basis functions. The use of MTA and the inherently parallel nature of the fragment calculations enables a rapid and accurate calculation of the IR spectrum. The applicability of MTA to optimize the protein geometry and evaluate its IR spectrum employing a polarizable continuum model with water as a solvent is also showcased. The typical errors in the total energy and IR frequencies computed by MTA vis-à-vis their full calculation (FC) counterparts for the studied protein are 5-10 millihartrees and 5 cm-1, respectively. Moreover, due to the independent execution of the fragments, large-scale parallelization can also be achieved. With increasing size and level of theory, MTA shows an appreciable advantage in computer time as well as memory and disk space requirement over the corresponding FCs. The present study suggests that the geometry optimization and IR computations on the biomolecules containing ∼1000 atoms and/or ∼15 000 basis functions using MTA and HPC facility can be clearly envisioned in the near future.
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Affiliation(s)
- Nityananda Sahu
- Theoretische Chemie, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Subodh S Khire
- RIKEN Center for Computational Science, Kobe 650-0047, Japan
| | - Shridhar R Gadre
- Departments of Scientific Computing, Modelling & Simulation and Chemistry, Savitribai Phule Pune University, Pune 411007, India
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3
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Dang TT, Huang YH, Ott S, Harvey PJ, Gilding EK, Tombling BJ, Chan LY, Kaas Q, Claridge-Chang A, Craik DJ. The acyclotide ribe 31 from Rinorea bengalensis has selective cytotoxicity and potent insecticidal properties in Drosophila. J Biol Chem 2022; 298:102413. [PMID: 36007611 PMCID: PMC9513267 DOI: 10.1016/j.jbc.2022.102413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022] Open
Abstract
Cyclotides and acyclic versions of cyclotides (acyclotides) are peptides involved in plant defense. These peptides contain a cystine knot motif formed by three interlocked disulfide bonds, with the main difference between the two classes being the presence or absence of a cyclic backbone, respectively. The insecticidal activity of cyclotides is well documented, but no study to date explores the insecticidal activity of acyclotides. Here, we present the first in vivo evaluation of the insecticidal activity of acyclotides from Rinorea bengalensis on the vinegar fly Drosophila melanogaster. Of a group of structurally comparable acyclotides, ribe 31 showed the most potent toxicity when fed to D. melanogaster. We screened a range of acyclotides and cyclotides and found their toxicity toward human red blood cells was substantially lower than toward insect cells, highlighting their selectivity and potential for use as bioinsecticides. Our confocal microscopy experiments indicated their cytotoxicity is likely mediated via membrane disruption. Furthermore, our surface plasmon resonance studies suggested ribe 31 preferentially binds to membranes containing phospholipids with phosphatidyl-ethanolamine headgroups. Despite having an acyclic backbone, we determined the three-dimensional NMR solution structure of ribe 31 is similar to that of cyclotides. In summary, our results suggest that, with further optimization, ribe 31 could have applications as an insecticide due to its potent in vivo activity against D. melanogaster. More broadly, this work advances the field by demonstrating that acyclotides are more common than previously thought, have potent insecticidal activity, and have the advantage of potentially being more easily manufactured than cyclotides.
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Affiliation(s)
- Tien T Dang
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Yen-Hua Huang
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Stanislav Ott
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, 169857
| | - Peta J Harvey
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Edward K Gilding
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Benjamin J Tombling
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Lai Y Chan
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Adam Claridge-Chang
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, 169857; Institute for Molecular and Cell Biology, A*STAR, Singapore, 138673; Department of Physiology, National University of Singapore, Singapore, 117593
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia.
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4
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Wu WH, Guo J, Zhang L, Zhang WB, Gao W. Peptide/protein-based macrocycles: from biological synthesis to biomedical applications. RSC Chem Biol 2022; 3:815-829. [PMID: 35866174 PMCID: PMC9257627 DOI: 10.1039/d1cb00246e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 06/08/2022] [Indexed: 11/21/2022] Open
Abstract
Living organisms have evolved cyclic or multicyclic peptides and proteins with enhanced stability and high bioactivity superior to their linear counterparts for diverse purposes. Herein, we review recent progress in applying this concept to artificial peptides and proteins to exploit the functional benefits of these macrocycles. Not only have simple cyclic forms been prepared, numerous macrocycle variants, such as knots and links, have also been developed. The chemical tools and synthetic strategies are summarized for the biological synthesis of these macrocycles, demonstrating it as a powerful alternative to chemical synthesis. Its further application to therapeutic peptides/proteins has led to biomedicines with profoundly improved pharmaceutical performances. Finally, we present our perspectives on the field and its future developments.
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Affiliation(s)
- Wen-Hao Wu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 P. R. China
| | - Jianwen Guo
- Department of Geriatric Dentistry, Beijing Laboratory of Biomedical Materials, Peking University School and Hospital of Stomatology Beijing 100081 P. R. China
- Biomedical Engineering Department, Peking University Beijing 100191 P. R. China
| | - Longshuai Zhang
- Department of Geriatric Dentistry, Beijing Laboratory of Biomedical Materials, Peking University School and Hospital of Stomatology Beijing 100081 P. R. China
- Biomedical Engineering Department, Peking University Beijing 100191 P. R. China
| | - Wen-Bin Zhang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 P. R. China
| | - Weiping Gao
- Department of Geriatric Dentistry, Beijing Laboratory of Biomedical Materials, Peking University School and Hospital of Stomatology Beijing 100081 P. R. China
- Biomedical Engineering Department, Peking University Beijing 100191 P. R. China
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5
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Dayani L, Dinani MS, Aliomrani M, Hashempour H, Varshosaz J, Taheri A. Immunomodulatory effects of cyclotides isolated from Viola odorata in an experimental autoimmune encephalomyelitis animal model of multiple sclerosis. Mult Scler Relat Disord 2022; 64:103958. [PMID: 35716476 DOI: 10.1016/j.msard.2022.103958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 04/19/2022] [Accepted: 06/09/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND Multiple sclerosis (MS) is a demyelinating disease of the central nervous system that causes chronic inflammation. Cyclotides are small plant proteins with a wide range of biological activity, making them a target for researchers to investigate. This study was conducted to investigate the possible effects of cyclotide-rich fractions from Viola odorata as an immunomodulatory agent in an experimental autoimmune encephalomyelitis (EAE) model of MS. METHODS At room temperature, the plant materials were subjected to maceration in methanol: dichloromethane (1:1; v/v) for 3 days. The extraction was repeated 3 times, and the final concentrated extract was partitioned 3 times by 1/2 volume of double-distilled water. The aqueous phases were separated and freeze-dried. Finally, the crude extract was fractionated by C18 silicagel using vacuum liquid chromatography, with mobile phases of 30%, 50% and 80% of ethanol: water, respectively. The 50%, and 80% fractions were analyzed by HPLC and MALDI-TOF analysis and administrated intraperitoneally to forty-five female C57BL/6 EAE-induced mice, at 5, 25, and 50 mg/kg doses. After 28 days, the animals were evaluated using EAE clinical scoring which was done every 3 days, cytokine levels, and myelination level. RESULTS The results confirmed the presence of cyclotides in V. odorata based on their retention time and the composition of mobile phase in HPLC and the molecular weight of the peaks in MALDI-TOF analysis. It was observed that cyclotides, especially in the 80% fraction group at the dose of 50 mg/kg significantly reduced the clinical scores, inflammation, and demyelination in EAE mice compared with the normal saline group (P<0.05), and the results of this group were comparable with fingolimod (P>0.05). CONCLUSION It could be concluded that V. odorata is a rich source of cyclotides which they could be extracted by an easily available process and also, they could be used as immunomodulatory agents in MS, with similar effects to fingolimod.
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Affiliation(s)
- Ladan Dayani
- Novel Drug Delivery Systems Research Centre, Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Pharmaceutics, Faculty of Pharmacy and Novel Drug Delivery Systems Research Centre, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Masoud Sadeghi Dinani
- Department of Pharmacognosy, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mehdi Aliomrani
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hossein Hashempour
- Department of Chemistry, Faculty of Basic Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran
| | - Jaleh Varshosaz
- Novel Drug Delivery Systems Research Centre, Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Pharmaceutics, Faculty of Pharmacy and Novel Drug Delivery Systems Research Centre, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Azade Taheri
- Novel Drug Delivery Systems Research Centre, Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Pharmaceutics, Faculty of Pharmacy and Novel Drug Delivery Systems Research Centre, Isfahan University of Medical Sciences, Isfahan, Iran.
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6
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Du Q, Huang YH, Wang CK, Kaas Q, Craik DJ. Mutagenesis of bracelet cyclotide hyen D reveals functionally and structurally critical residues for membrane binding and cytotoxicity. J Biol Chem 2022; 298:101822. [PMID: 35283188 PMCID: PMC9006653 DOI: 10.1016/j.jbc.2022.101822] [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: 09/14/2021] [Revised: 02/19/2022] [Accepted: 02/21/2022] [Indexed: 11/05/2022] Open
Abstract
Cyclotides have a wide range of bioactivities relevant for agricultural and pharmaceutical applications. This large family of naturally occurring macrocyclic peptides is divided into three subfamilies, with the bracelet subfamily being the largest and comprising the most potent cyclotides reported to date. However, attempts to harness the natural bioactivities of bracelet cyclotides and engineer-optimized analogs have been hindered by a lack of understanding of the structural and functional role of their constituent residues, which has been challenging because bracelet cyclotides are difficult to produce synthetically. We recently established a facile strategy to make the I11L mutant of cyclotide hyen D that is as active as the parent peptide, enabling the subsequent production of a series of variants. In the current study, we report an alanine mutagenesis structure-activity study of [I11L] hyen D to probe the role of individual residues on peptide folding using analytical chromatography, on molecular function using surface plasmon resonance, and on therapeutic potential using cytotoxicity assays. We found that Glu-6 and Thr-15 are critical for maintaining the structure of bracelet cyclotides and that hydrophobic residues in loops 2 and 3 are essential for membrane binding and cytotoxic activity, findings that are distinct from the structural and functional characteristics determined for other cyclotide subfamilies. In conclusion, this is the first report of a mutagenesis scan conducted on a bracelet cyclotide, offering insights into their function and supporting future efforts to engineer bracelet cyclotides for biotechnological applications.
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Affiliation(s)
- Qingdan Du
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD, Australia
| | - Yen-Hua Huang
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD, Australia.
| | - Conan K Wang
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD, Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD, Australia
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD, Australia.
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7
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Hellinger R, Muratspahić E, Devi S, Koehbach J, Vasileva M, Harvey PJ, Craik DJ, Gründemann C, Gruber CW. Importance of the Cyclic Cystine Knot Structural Motif for Immunosuppressive Effects of Cyclotides. ACS Chem Biol 2021; 16:2373-2386. [PMID: 34592097 PMCID: PMC9286316 DOI: 10.1021/acschembio.1c00524] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The cyclotide T20K inhibits the proliferation of human immune cells and is currently in clinical trials for multiple sclerosis. Here, we provide novel functional data and mechanistic insights into structure-activity relationships of T20K. Analogs with partial or complete reduction of the cystine knot had loss of function in proliferation experiments. Similarly, an acyclic analog of T20K was inactive in lymphocyte bioassays. The lack of activity of non-native peptide analogs appears to be associated with the ability of cyclotides to interact with and penetrate cell membranes, since cellular uptake studies demonstrated fast fractional transfer only of the native peptide into the cytosol of human immune cells. Therefore, structural differences between cyclic and linear native folded peptides were investigated by NMR to elucidate structure-activity relationships. Acyclic T20K had a less rigid backbone and considerable structural changes in loops 1 and 6 compared to the native cyclic T20K, supporting the idea that the cyclic cystine knot motif is a unique bioactive scaffold. This study provides evidence that this structural motif in cyclotides governs bioactivity, interactions with and transport across biological membranes, and the structural integrity of these peptides. These observations could be useful to understand the structure-activity of other cystine knot proteins due to the structural conservation of the cystine knot motif across evolution and to provide guidance for the design of novel cyclic cysteine-stabilized molecules.
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Affiliation(s)
- Roland Hellinger
- Center for
Physiology and Pharmacology, Medical University
of Vienna, Schwarzspanierstr. 17, Vienna 1090, Austria
| | - Edin Muratspahić
- Center for
Physiology and Pharmacology, Medical University
of Vienna, Schwarzspanierstr. 17, Vienna 1090, Austria
| | - Seema Devi
- Institute
for Infection Prevention and Hospital Epidemiology, Center for Complementary
Medicine, Faculty of Medicine, University
of Freiburg, Breisacher Str. 115B, Freiburg 79106, Germany
| | - Johannes Koehbach
- Institute
for Molecular Bioscience, Australian Research Council Centre of Excellence
for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Mina Vasileva
- Center for
Physiology and Pharmacology, Medical University
of Vienna, Schwarzspanierstr. 17, Vienna 1090, Austria
| | - Peta J. Harvey
- Institute
for Molecular Bioscience, Australian Research Council Centre of Excellence
for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - David J. Craik
- Institute
for Molecular Bioscience, Australian Research Council Centre of Excellence
for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Carsten Gründemann
- Translational
Complementary Medicine, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstr. 80, Basel 4056, Switzerland
| | - Christian W. Gruber
- Center for
Physiology and Pharmacology, Medical University
of Vienna, Schwarzspanierstr. 17, Vienna 1090, Austria
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8
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Huang YH, Du Q, Jiang Z, King GJ, Collins BM, Wang CK, Craik DJ. Enabling Efficient Folding and High-Resolution Crystallographic Analysis of Bracelet Cyclotides. Molecules 2021; 26:5554. [PMID: 34577034 PMCID: PMC8467136 DOI: 10.3390/molecules26185554] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/05/2021] [Accepted: 09/09/2021] [Indexed: 11/23/2022] Open
Abstract
Cyclotides have attracted great interest as drug design scaffolds because of their unique cyclic cystine knotted topology. They are classified into three subfamilies, among which the bracelet subfamily represents the majority and comprises the most bioactive cyclotides, but are the most poorly utilized in drug design applications. A long-standing challenge has been the very low in vitro folding yields of bracelets, hampering efforts to characterize their structures and activities. Herein, we report substantial increases in bracelet folding yields enabled by a single point mutation of residue Ile-11 to Leu or Gly. We applied this discovery to synthesize mirror image enantiomers and used quasi-racemic crystallography to elucidate the first crystal structures of bracelet cyclotides. This study provides a facile strategy to produce bracelet cyclotides, leading to a general method to easily access their atomic resolution structures and providing a basis for development of biotechnological applications.
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Affiliation(s)
- Yen-Hua Huang
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (Y.-H.H.); (Q.D.); (Z.J.); (B.M.C.); (C.K.W.)
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Qingdan Du
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (Y.-H.H.); (Q.D.); (Z.J.); (B.M.C.); (C.K.W.)
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Zhihao Jiang
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (Y.-H.H.); (Q.D.); (Z.J.); (B.M.C.); (C.K.W.)
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Gordon J. King
- The Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD 4072, Australia;
| | - Brett M. Collins
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (Y.-H.H.); (Q.D.); (Z.J.); (B.M.C.); (C.K.W.)
| | - Conan K. Wang
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (Y.-H.H.); (Q.D.); (Z.J.); (B.M.C.); (C.K.W.)
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia
| | - David J. Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (Y.-H.H.); (Q.D.); (Z.J.); (B.M.C.); (C.K.W.)
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia
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9
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van den Broek K, Epple M, Kersten LS, Kuhn H, Zielesny A. Quantitative Estimation of Cyclotide-Induced Bilayer Membrane Disruption by Lipid Extraction with Mesoscopic Simulation. J Chem Inf Model 2021; 61:3027-3040. [PMID: 34008405 DOI: 10.1021/acs.jcim.1c00332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclotide-induced membrane disruption is studied at the microsecond timescale by dissipative particle dynamics to quantitatively estimate a kinetic rate constant for membrane lipid extraction with a ″sandwich″ interaction model where two bilayer membranes enclose a cyclotide/water compartment. The obtained bioactivity trends for cyclotides Kalata B1, Cycloviolacin O2, and selected mutants with different membrane types are in agreement with experimental findings: For all membranes investigated, Cycloviolacin O2 shows a higher lipid extraction activity than Kalata B1. The presence of cholesterol leads to a decreased cyclotide activity compared to cholesterol-free membranes. Phosphoethanolamine-rich membranes exhibit an increased membrane disruption. A cyclotide's ″hydrophobic patch″ surface area is important for its bioactivity. A replacement of or with charged amino acid residues may lead to super-mutants with above-native activity but without simple charge-activity patterns. Cyclotide mixtures show linearly additive bioactivities without significant sub- or over-additive effects. The proposed method can be applied as a fast and easy-to-use tool for exploring structure-activity relationships of cyclotide/membrane systems: With the open software provided, the rate constant of a single cyclotide/membrane system can be determined in about 1 day by a scientific end-user without programming skills.
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Affiliation(s)
- Karina van den Broek
- Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, 45141 Essen, Germany.,Institute for Bioinformatics and Chemoinformatics, Westphalian University of Applied Sciences, 45665 Recklinghausen, Germany
| | - Matthias Epple
- Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, 45141 Essen, Germany
| | - Lisa Sophie Kersten
- Institute for Bioinformatics and Chemoinformatics, Westphalian University of Applied Sciences, 45665 Recklinghausen, Germany
| | - Hubert Kuhn
- CAM-D Technologies GmbH, 42697 Solingen, Germany
| | - Achim Zielesny
- Institute for Bioinformatics and Chemoinformatics, Westphalian University of Applied Sciences, 45665 Recklinghausen, Germany
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10
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Crystal structure and site-directed mutagenesis of circular bacteriocin plantacyclin B21AG reveals cationic and aromatic residues important for antimicrobial activity. Sci Rep 2020; 10:17398. [PMID: 33060678 PMCID: PMC7562740 DOI: 10.1038/s41598-020-74332-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/21/2020] [Indexed: 12/02/2022] Open
Abstract
Plantacyclin B21AG is a circular bacteriocin produced by Lactiplantibacillus plantarum B21 which displays antimicrobial activity against various Gram-positive bacteria including foodborne pathogens, Listeria monocytogenes and Clostridium perfringens. It is a 58-amino acid cyclised antimicrobial peptide, with the N and C termini covalently linked together. The circular peptide backbone contributes to remarkable stability, conferring partial proteolytic resistance and structural integrity under a wide temperature and pH range. Here, we report the first crystal structure of a circular bacteriocin from a food grade Lactobacillus. The protein was crystallised using the hanging drop vapour diffusion method and the structure solved to a resolution of 1.8 Å. Sequence alignment against 18 previously characterised circular bacteriocins revealed the presence of conserved charged and aromatic residues. Alanine substitution mutagenesis validated the importance of these residues. Minimum inhibitory concentration analysis of these Ala mutants showed that Phe8Ala and Trp45Ala mutants displayed a 48- and 32-fold reduction in activity, compared to wild type. The Lys19Ala mutant displayed the weakest activity, with a 128-fold reduction. These experiments demonstrate the relative importance of aromatic and cationic residues for the antimicrobial activity of plantacyclin B21AG and by extension, other circular bacteriocins sharing these evolutionarily conserved residues.
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11
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Handley TNG, Wang CK, Harvey PJ, Lawrence N, Craik DJ. Cyclotide Structures Revealed by NMR, with a Little Help from X‐ray Crystallography. Chembiochem 2020; 21:3463-3475. [DOI: 10.1002/cbic.202000315] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/08/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Thomas N. G. Handley
- Institute for Molecular Bioscience Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science The University of Queensland Brisbane Queensland 4072 Australia
| | - Conan K. Wang
- Institute for Molecular Bioscience Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science The University of Queensland Brisbane Queensland 4072 Australia
| | - Peta J. Harvey
- Institute for Molecular Bioscience Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science The University of Queensland Brisbane Queensland 4072 Australia
| | - Nicole Lawrence
- Institute for Molecular Bioscience Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science The University of Queensland Brisbane Queensland 4072 Australia
| | - David J. Craik
- Institute for Molecular Bioscience Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science The University of Queensland Brisbane Queensland 4072 Australia
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12
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Srivastava S, Dashora K, Ameta KL, Singh NP, El-Enshasy HA, Pagano MC, Hesham AEL, Sharma GD, Sharma M, Bhargava A. Cysteine-rich antimicrobial peptides from plants: The future of antimicrobial therapy. Phytother Res 2020; 35:256-277. [PMID: 32940412 DOI: 10.1002/ptr.6823] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/26/2020] [Accepted: 07/03/2020] [Indexed: 12/13/2022]
Abstract
There has been a spurt in the spread of microbial resistance to antibiotics due to indiscriminate use of antimicrobial agents in human medicine, agriculture, and animal husbandry. It has been realized that conventional antibiotic therapy would be less effective in the coming decades and more emphasis should be given for the development of novel antiinfective therapies. Cysteine rich peptides (CRPs) are broad-spectrum antimicrobial agents that modulate the innate immune system of different life forms such as bacteria, protozoans, fungi, plants, insects, and animals. These are also expressed in several plant tissues in response to invasion by pathogens, and play a crucial role in the regulation of plant growth and development. The present work explores the importance of CRPs as potent antimicrobial agents, which can supplement and/or replace the conventional antibiotics. Different plant parts of diverse plant species showed the presence of antimicrobial peptides (AMPs), which had significant structural and functional diversity. The plant-derived AMPs exhibited potent activity toward a range of plant and animal pathogens, protozoans, insects, and even against cancer cells. The cysteine-rich AMPs have opened new avenues for the use of plants as biofactories for the production of antimicrobials and can be considered as promising antimicrobial drugs in biotherapeutics.
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Affiliation(s)
- Shilpi Srivastava
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow Campus, Lucknow, India
| | - Kavya Dashora
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi, India
| | - Keshav Lalit Ameta
- Department of Chemistry, School of Liberal Arts and Sciences, Mody University of Science and Technology, Lakshmangarh, Rajasthan, India
| | | | - Hesham Ali El-Enshasy
- Institute of Bioproduct Development (IBD), School of Chemical and Energy Engineering, Universiti Teknologi Malaysia (UTM), Skudai, Johor Bahru, Malaysia.,City of Scientific Research and Technology Applications (SRTA), New Burg Al Arab, Alexandria, Egypt
| | | | - Abd El-Latif Hesham
- Genetics Department, Faculty of Agriculture, Beni-Suef University, Beni-Suef, Egypt
| | | | - Minaxi Sharma
- Department of Food Technology, Akal College of Agriculture, Eternal University, Baru Sahib, India
| | - Atul Bhargava
- Department of Botany, Mahatma Gandhi Central University, Motihari, India
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13
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Tammineni R, Gulati P, Kumar S, Mohanty A. An overview of acyclotides: Past, present and future. PHYTOCHEMISTRY 2020; 170:112215. [PMID: 31812106 DOI: 10.1016/j.phytochem.2019.112215] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 06/10/2023]
Abstract
Acyclotides are plant-based, acyclic miniproteins with cystine knot motif formed by three conserved disulfide linkages and lack head to tail ligation. Acyclotides may not necessarily be less stable, even though they lack cyclic backbone, as the conserved cystine knot feature provides the required stability. Violacin A was the first acyclotide, isolated from Viola odorata in 2006. Until now, acyclotides have been reported from five dicot families (Violaceae, Rubiaceae, Cucurbitaceae, Solanaceae, Fabaceae) and one monocot family (Poaceae). In Poaceae, only acyclotides have been found whereas in dicot families both cyclotides and acyclotides have been isolated. In last 15 years, several acyclotides with antimicrobial, cytotoxic and hemolytic bioactivities have been discovered. Thus, although many naturally expressed acyclotides do exhibit bioactivities, the linearization of the cyclic peptides may result in loss of bioactivities. Although, bioactivities of acyclotides are comparable to their cyclic counterparts, the numbers of isolated acyclotides are still few. Further, those discovered, have the scope to be screened for agriculturally important activities (insecticidal, anti-helminthic, molluscicidal) and pharmaceutical properties (anticancer, anti-HIV, immuno-stimulant). The feasibility of application of acyclotides is because of their relatively less complex biological synthesis compared to cyclotides, as the cyclization step is not needed. This attribute facilitates the production of transgenic crops and/or its expression in heterologous organisms, lacking cyclization machinery. Keeping in view the bioactivities and the wide array of emerging potential applications of acyclotides, the present review discusses their distribution in plants, gene and protein structure, biosynthesis, bioactivities and mechanism of action. Further, their potential applications and future perspectives to exploit them in agriculture and pharmaceutical industries have been highlighted.
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Affiliation(s)
- Ramya Tammineni
- Bioinformatics Infrastructure Facility, Gargi College, University of Delhi, India
| | - Pooja Gulati
- Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana, India
| | - Sanjay Kumar
- Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana, India
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14
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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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15
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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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16
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Atakisi H, Conger L, Moreau DW, Thorne RE. Resolution and dose dependence of radiation damage in biomolecular systems. IUCRJ 2019; 6:1040-1053. [PMID: 31709060 PMCID: PMC6830208 DOI: 10.1107/s2052252519008777] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 06/19/2019] [Indexed: 05/30/2023]
Abstract
The local Fourier-space relation between diffracted intensity I, diffraction wavevector q and dose D, , is key to probing and understanding radiation damage by X-rays and energetic particles in both diffraction and imaging experiments. The models used in protein crystallography for the last 50 years provide good fits to experimental I(q) versus nominal dose data, but have unclear physical significance. More recently, a fit to diffraction and imaging experiments suggested that the maximum tolerable dose varies as q -1 or linearly with resolution. Here, it is shown that crystallographic data have been strongly perturbed by the effects of spatially nonuniform crystal irradiation and diffraction during data collection. Reanalysis shows that these data are consistent with a purely exponential local dose dependence, = I 0(q)exp[-D/D e(q)], where D e(q) ∝ q α with α ≃ 1.7. A physics-based model for radiation damage, in which damage events occurring at random locations within a sample each cause energy deposition and blurring of the electron density within a small volume, predicts this exponential variation with dose for all q values and a decay exponent α ≃ 2 in two and three dimensions, roughly consistent with both diffraction and imaging experiments over more than two orders of magnitude in resolution. The B-factor model used to account for radiation damage in crystallographic scaling programs is consistent with α = 2, but may not accurately capture the dose dependencies of structure factors under typical nonuniform illumination conditions. The strong q dependence of radiation-induced diffraction decays implies that the previously proposed 20-30 MGy dose limit for protein crystallography should be replaced by a resolution-dependent dose limit that, for atomic resolution data sets, will be much smaller. The results suggest that the physics underlying basic experimental trends in radiation damage at T ≃ 100 K is straightforward and universal. Deviations of the local I(q, D) from strictly exponential behavior may provide mechanistic insights, especially into the radiation-damage processes responsible for the greatly increased radiation sensitivity observed at T ≃ 300 K.
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Affiliation(s)
- Hakan Atakisi
- Physics Department, Cornell University, Ithaca, NY 14853, USA
| | | | - David W. Moreau
- Physics Department, Cornell University, Ithaca, NY 14853, USA
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17
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Jones PM, Mazzio E, Soliman K, George AM. In Silico Investigation of the Binding of MCoTI-II Plant Defense Knottin to the γ-NGF Serine Protease of the 7S Nerve Growth Factor Complex and Biological Activity of Its NGF Mimetic Properties. J Phys Chem B 2019; 123:9104-9110. [PMID: 31580077 DOI: 10.1021/acs.jpcb.9b07547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nerve growth factor (NGF) is an endogenously produced polypeptide that promotes the differentiation, survival, and repair of neurons in the central and peripheral nervous systems. While trophic proteins hold promise for the treatment of neuronal injury and disease, use of NGF is limited by its large molecular weight, lack of permeability through the blood-brain barrier, and peripheral side effects. Previously, we found that an extract of the Momordica cochinchinensis seed stimulated PC-12 neurite outgrowth. Bioactivity-guided fractioning of the seed extract suggested that the NGF mimetic agent was one of few defined proteins from this plant: one group being the defense Knottins and the other group of the lowest mass is the potent trypsin inhibitor MCoTI-II. Here, the NGF mimetic potential of this latter protein was investigated using two concurrent but different approaches. A biological study used recombinant purified MCoTI-II, which when tested in rat PC-12 cells grown on collagen, failed to initiate outgrowth relative to the positive control 7S NGF. In a separate computational study, the possibility was investigated such that MCoTI-II could exert an effect through binding to the serine protease γ-NGF subunit of the 7S NGF complex, analogous to its binding to its native receptor trypsin. Molecular dynamics simulations showed that MCoTI-II can bind stably to γ-NGF for >350 ns. Modeling indicated that this interaction could sterically inhibit 7S NGF complex formation, potentially altering the equilibrium between inactive complexed and free active NFG protein. In conclusion, the biological study now excludes the MCoTI-II protein as the NGF mimetic factor in the Momordica extract, an important and required step to identify the active component in this seed. On the other hand, the theoretical study has revealed a novel observation that may be of use in the development of strategies to affect NGF activity.
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Affiliation(s)
- Peter M Jones
- School of Life Sciences , University of Technology Sydney , P.O. Box 123, Broadway , New South Wales 2007 , Australia
| | - Elizabeth Mazzio
- College of Pharmacy and Pharmaceutical Sciences , Florida Agricultural and Mechanical University , 241 Fred Humphries Science Research Facility , Tallahassee , Florida 32307 , United States
| | - Karam Soliman
- College of Pharmacy and Pharmaceutical Sciences , Florida Agricultural and Mechanical University , 241 Fred Humphries Science Research Facility , Tallahassee , Florida 32307 , United States
| | - Anthony M George
- School of Life Sciences , University of Technology Sydney , P.O. Box 123, Broadway , New South Wales 2007 , Australia
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18
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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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19
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Lawrence N, Wu B, Ligutti J, Cheneval O, Agwa AJ, Benfield AH, Biswas K, Craik DJ, Miranda LP, Henriques ST, Schroeder CI. Peptide-Membrane Interactions Affect the Inhibitory Potency and Selectivity of Spider Toxins ProTx-II and GpTx-1. ACS Chem Biol 2019; 14:118-130. [PMID: 30507158 DOI: 10.1021/acschembio.8b00989] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Gating modifier toxins (GMTs) from spider venom can inhibit voltage gated sodium channels (NaVs) involved in pain signal transmission, including the NaV1.7 subtype. GMTs have a conserved amphipathic structure that allow them to interact with membranes and also with charged residues in regions of NaV that are exposed at the cell surface. ProTx-II and GpTx-1 are GMTs able to inhibit NaV1.7 with high potency, but they differ in their ability to bind to membranes and in their selectivity over other NaV subtypes. To explore these differences and gain detailed information on their membrane-binding ability and how this relates to potency and selectivity, we examined previously described NaV1.7 potent/selective GpTx-1 analogues and new ProTx-II analogues designed to reduce membrane binding and improve selectivity for NaV1.7. Our studies reveal that the number and type of hydrophobic residues as well as how they are presented at the surface determine the affinity of ProTx-II and GpTx-1 for membranes and that altering these residues can have dramatic effects on NaV inhibitory activity. We demonstrate that strong peptide-membrane interactions are not essential for inhibiting NaV1.7 and propose that hydrophobic interactions instead play an important role in positioning the GMT at the membrane surface proximal to exposed NaV residues, thereby affecting peptide-channel interactions. Our detailed structure-activity relationship study highlights the challenges of designing GMT-based molecules that simultaneously achieve high potency and selectivity for NaV1.7, as single mutations can induce local changes in GMT structure that can have a major impact on NaV-inhibitory activity.
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Affiliation(s)
- Nicole Lawrence
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | | | - Joseph Ligutti
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Olivier Cheneval
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Akello Joanna Agwa
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Aurélie H. Benfield
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | | | | | | | - Sónia Troeira Henriques
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Christina I. Schroeder
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
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20
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Campos ML, de Souza CM, de Oliveira KBS, Dias SC, Franco OL. The role of antimicrobial peptides in plant immunity. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:4997-5011. [PMID: 30099553 DOI: 10.1093/jxb/ery294] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 07/31/2018] [Indexed: 05/21/2023]
Abstract
Selective pressure imposed by millions of years of relentless biological attack has led to the development of an extraordinary array of defense strategies in plants. Among these, antimicrobial peptides (AMPs) stand out as one of the most prominent components of the plant immune system. These small and usually basic peptides are deployed as a generalist defense strategy that grants direct and durable resistance against biotic stress. Even though their name implies a function against microbes, the range of plant-associated organisms affected by these peptides is much broader. In this review, we highlight the advances in our understanding on the role of AMPs in plant immunity. We demonstrate that the capacity of plant AMPs to act against a large spectrum of enemies relies on their diverse mechanism of action and remarkable structural stability. The efficacy of AMPs as a defense strategy is evidenced by their widespread occurrence in the plant kingdom, an astonishing heterogeneity in host peptide composition, and the extent to which plant enemies have evolved effective counter-measures to evade AMP action. Plant AMPs are becoming an important topic of research due to their significance in allowing plants to thrive and for their enormous potential in agronomical and pharmaceutical fields.
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Affiliation(s)
- Marcelo Lattarulo Campos
- Centro de Análises Bioquímicas e Proteômicas, Universidade Católica de Brasilia, Brasilia/DF, Brazil
- Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá/MT, Brazil
| | - Camila Maurmann de Souza
- Centro de Análises Bioquímicas e Proteômicas, Universidade Católica de Brasilia, Brasilia/DF, Brazil
| | | | - Simoni Campos Dias
- Centro de Análises Bioquímicas e Proteômicas, Universidade Católica de Brasilia, Brasilia/DF, Brazil
- Universidade de Brasilia, Pós-Graduação em Biologia Animal, Campus Darcy Ribeiro, Brasilia/DF, Brazil
| | - Octávio Luiz Franco
- Centro de Análises Bioquímicas e Proteômicas, Universidade Católica de Brasilia, Brasilia/DF, Brazil
- S-Inova Biotech, Universidade Católica Dom Bosco, Campo Grande/MS, Brazil
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Bernardino K, Pinto MEF, Bolzani VS, de Moura AF, Batista Junior JM. Pinpointing disulfide connectivities in cysteine-rich proteins. Chem Commun (Camb) 2018; 53:7337-7340. [PMID: 28508909 DOI: 10.1039/c7cc02333b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A simple MD-based protocol is presented to accurately predict both the sequence and order of disulfide bond formation in proteins containing multiple cysteine residues. It provides a detailed description of their dynamical and structural features, which can be used to perform ensemble-averaged ECD calculations. Plant cyclotides are used as model compounds.
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Affiliation(s)
- K Bernardino
- Department of Chemistry, Federal University of São Carlos - UFSCar, São Carlos, SP 13565-905, Brazil.
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22
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Velasques J, Cardoso MH, Abrantes G, Frihling BE, Franco OL, Migliolo L. The rescue of botanical insecticides: A bioinspiration for new niches and needs. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2017; 143:14-25. [PMID: 29183583 DOI: 10.1016/j.pestbp.2017.10.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 09/12/2017] [Accepted: 10/04/2017] [Indexed: 06/07/2023]
Abstract
Crop protection is the basis of plant production and food security. Additionally, there are many efforts focused on increasing defensive mechanisms in order to avoid the damaging effects of insects, which still represent significant losses worldwide. Plants have naturally evolved different mechanisms to discourage herbivory, including chemical barriers such as the induction of defensive proteins and secondary metabolites, some of which have a historical link with bio-farming practices and others that are yet to be used. In the context of global concern regarding health and environmental impacts, which has been translated into political action and restrictions on the use of synthetic pesticides, this review deals with a description of some historical commercial phytochemicals and promising proteinaceous compounds that plants may modulate to defeat insect attacks. We present a broader outlook on molecular structure and mechanisms of action while we discuss possible tools to achieve effective methods for the biological control of pests, either by the formulation of products or by the development of new plant varieties with enhanced chemical defenses.
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Affiliation(s)
- Jannaina Velasques
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil
| | - Marlon Henrique Cardoso
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil; Programa de Pós Graduação em Patologia Molecular, Faculdade de Medicina, Universidade de Brasília, Brasília, DF, Brazil; Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil
| | - Guilherme Abrantes
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil
| | - Breno Emanuel Frihling
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil
| | - Octávio Luiz Franco
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil; Programa de Pós Graduação em Patologia Molecular, Faculdade de Medicina, Universidade de Brasília, Brasília, DF, Brazil; Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil
| | - Ludovico Migliolo
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil.
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23
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Investigation of Antimicrobial Peptide Genes Associated with Fungus and Insect Resistance in Maize. Int J Mol Sci 2017; 18:ijms18091938. [PMID: 28914754 PMCID: PMC5618587 DOI: 10.3390/ijms18091938] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/04/2017] [Accepted: 09/06/2017] [Indexed: 11/17/2022] Open
Abstract
Antimicrobial peptides (AMPs) are small defense proteins present in various organisms. Major groups of AMPs include beta-barrelin, hevein, knottin, lipid transfer protein (LTP), thionin, defensin, snakin, and cyclotide. Most plant AMPs involve host plant resistance to pathogens such as fungi, viruses, and bacteria, whereas a few plant AMPs from the cyclotide family carry insecticidal functions. In this research, a genome-wide investigation on antimicrobial peptide genes in maize genome was conducted. AMPs previously identified from various plant species were used as query sequences for maize genome data mining. Thirty-nine new maize AMPs were identified in addition to seven known maize AMPs. Protein sequence analysis revealed 10 distinguishable maize AMP groups. Analysis of mRNA expression of maize AMP genes by quantitative real-time polymerase chain reaction (qRT-PCR) revealed different expression patterns in a panel of 10 maize inbred lines. Five maize AMP genes were found significantly associated with insect or fungus resistance. Identification of maize antimicrobial peptide genes will facilitate the breeding of host plant resistance and improve maize production.
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24
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Hacker DE, Hoinka J, Iqbal ES, Przytycka TM, Hartman MCT. Highly Constrained Bicyclic Scaffolds for the Discovery of Protease-Stable Peptides via mRNA Display. ACS Chem Biol 2017; 12:795-804. [PMID: 28146347 DOI: 10.1021/acschembio.6b01006] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Highly constrained peptides such as the knotted peptide natural products are promising medicinal agents because of their impressive biostability and potent activity. Yet, libraries of highly constrained peptides are challenging to prepare. Here, we present a method which utilizes two robust, orthogonal chemical steps to create highly constrained bicyclic peptide libraries. This technology was optimized to be compatible with in vitro selections by mRNA display. We performed side-by-side monocyclic and bicyclic selections against a model protein (streptavidin). Both selections resulted in peptides with mid-nanomolar affinity, and the bicyclic selection yielded a peptide with remarkable protease resistance.
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Affiliation(s)
- David E. Hacker
- Virginia Commonwealth University, Department of Chemistry, 1001 West Main Street, Richmond, Virginia 23284-2006, United States
- National Center for Biotechnology Information, 8600 Rockville Pike, Bethesda, Maryland 20894, United States
| | - Jan Hoinka
- Virginia Commonwealth University, Department of Chemistry, 1001 West Main Street, Richmond, Virginia 23284-2006, United States
- National Center for Biotechnology Information, 8600 Rockville Pike, Bethesda, Maryland 20894, United States
| | - Emil S. Iqbal
- Virginia Commonwealth University, Department of Chemistry, 1001 West Main Street, Richmond, Virginia 23284-2006, United States
- National Center for Biotechnology Information, 8600 Rockville Pike, Bethesda, Maryland 20894, United States
| | - Teresa M. Przytycka
- Virginia Commonwealth University, Department of Chemistry, 1001 West Main Street, Richmond, Virginia 23284-2006, United States
- National Center for Biotechnology Information, 8600 Rockville Pike, Bethesda, Maryland 20894, United States
| | - Matthew C. T. Hartman
- Virginia Commonwealth University, Department of Chemistry, 1001 West Main Street, Richmond, Virginia 23284-2006, United States
- National Center for Biotechnology Information, 8600 Rockville Pike, Bethesda, Maryland 20894, United States
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25
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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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26
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Kuznetsova SS, Kolesanova EF, Talanova AV, Veselovsky AV. [Prospects for the design of new therapeutically significant protease inhibitors based on knottins and sunflower seed trypsin inhibitor (SFTI 1)]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2016; 62:353-68. [PMID: 27562989 DOI: 10.18097/pbmc20166204353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Plant seed knottins, mainly from the Cucurbitacea family, and sunflower seed trypsin inhibitor (SFTI 1) are the most low-molecular canonical peptide inhibitors of serine proteases. High efficiency of inhibition of various serine proteases, structure rigidity together with the possibility of limited variations of amino acid sequences, high chemical stability, lack of toxic properties, opportunity of production by either chemical synthesis or use of heterologous expression systems make these inhibitors attractive templates for design of new compounds for regulation of therapeutically significant serine protease activities. Hence the design of such compounds represents a prospective research field. The review considers structural characteristics of these inhibitors, their properties, methods of preparation and design of new analogs. Examples of successful employment of natural serine protease inhibitors belonging to knottin family and SFTI 1 as templates for the design of highly specific inhibitors of certain proteases are given.
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Affiliation(s)
| | | | - A V Talanova
- Institute of Biomedical Chemistry, Moscow, Russia; Pirogov Russian National Research Medical University, Moscow, Russia
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27
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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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28
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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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29
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Jones PM, George AM. Computational analysis of the MCoTI-II plant defence knottin reveals a novel intermediate conformation that facilitates trypsin binding. Sci Rep 2016; 6:23174. [PMID: 26975976 PMCID: PMC4791599 DOI: 10.1038/srep23174] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 02/25/2016] [Indexed: 11/09/2022] Open
Abstract
MCoTI-I and II are plant defence proteins, potent trypsin inhibitors from the bitter gourd Momordica cochinchinensis. They are members of the Knottin Family, which display exceptional stability due to unique topology comprising three interlocked disulfide bridges. Knottins show promise as scaffolds for new drug development. A crystal structure of trypsin-bound MCoTI-II suggested that loop 1, which engages the trypsin active site, would show decreased dynamics in the bound state, an inference at odds with an NMR analysis of MCoTI-I, which revealed increased dynamics of loop 1 in the presence of trypsin. To investigate this question, we performed unrestrained MD simulations of trypsin-bound and free MCoTI-II. This analysis found that loop 1 of MCoTI-II is not more dynamic in the trypsin-bound state than in the free state. However, it revealed an intermediate conformation, transitional between the free and bound MCoTI-II states. The data suggest that MCoTI-II binding involves a process in which initial interaction with trypsin induces transitions between the free and intermediate conformations, and fluctuations between these states account for the increase in dynamics of loop 1 observed for trypsin-bound MCoTI-I. The MD analysis thus revealed new aspects of the inhibitors’ dynamics that may be of utility in drug design.
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Affiliation(s)
- Peter M Jones
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007 Australia
| | - Anthony M George
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007 Australia
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30
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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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31
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Senthilkumar B, Kumar P, Rajasekaran R. In-Silico Template Selection of In-Vitro Evolved Kalata B1 ofOldenlandia Affinisfor Scaffolding Peptide-Based Drug Design. J Cell Biochem 2015; 117:66-73. [DOI: 10.1002/jcb.25248] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 05/29/2015] [Indexed: 12/20/2022]
Affiliation(s)
- B. Senthilkumar
- Bioinformatics Division; School of Bio Sciences and Technology; Vellore Institute of Technology University; Vellore 632014 Tamil Nadu India
| | - Prakash Kumar
- Bioinformatics Division; School of Bio Sciences and Technology; Vellore Institute of Technology University; Vellore 632014 Tamil Nadu India
| | - R. Rajasekaran
- Bioinformatics Division; School of Bio Sciences and Technology; Vellore Institute of Technology University; Vellore 632014 Tamil Nadu India
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32
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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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Abstract
BACKGROUND Chlorotoxin is a small scorpion peptide that inhibits glioma cell migration. We investigated the importance of a major component of chlorotoxin's chemical structure - four disulfide bonds - to its tertiary structure and biological function. RESULTS Five disulfide bond analogs of chlorotoxin were synthesized, with l-α-aminobutyric acid residues replacing each or all of the disulfide bonds. Chemical oxidation and circular dichroism experiments revealed that Cys III-VII and Cys V-VIII were essential for native structure formation. Cys I-IV and Cys II-VI were important for stability of enzymatic proteolysis but not for the inhibition of human umbilical vein endothelial cell migration. CONCLUSION The disulfide bonds of chlorotoxin are important for its structure and stability and have a minor role in its activity against cell migration.
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Rational design and synthesis of an orally bioavailable peptide guided by NMR amide temperature coefficients. Proc Natl Acad Sci U S A 2015; 111:17504-9. [PMID: 25416591 DOI: 10.1073/pnas.1417611111] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Enhancing the oral bioavailability of peptide drug leads is a major challenge in drug design. As such, methods to address this challenge are highly sought after by the pharmaceutical industry. Here, we propose a strategy to identify appropriate amides for N-methylation using temperature coefficients measured by NMR to identify exposed amides in cyclic peptides. N-methylation effectively caps these amides, modifying the overall solvation properties of the peptides and making them more membrane permeable. The approach for identifying sites for N-methylation is a rapid alternative to the elucidation of 3D structures of peptide drug leads, which has been a commonly used structure-guided approach in the past. Five leucine-rich peptide scaffolds are reported with selectively designed N-methylated derivatives. In vitro membrane permeability was assessed by parallel artificial membrane permeability assay and Caco-2 assay. The most promising N-methylated peptide was then tested in vivo. Here we report a novel peptide (15), which displayed an oral bioavailability of 33% in a rat model, thus validating the design approach. We show that this approach can also be used to explain the notable increase in oral bioavailability of a somatostatin analog.
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35
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Plant antimicrobial peptides as potential anticancer agents. BIOMED RESEARCH INTERNATIONAL 2015; 2015:735087. [PMID: 25815333 PMCID: PMC4359852 DOI: 10.1155/2015/735087] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/25/2014] [Accepted: 09/26/2014] [Indexed: 11/17/2022]
Abstract
Antimicrobial peptides (AMPs) are part of the innate immune defense mechanism of many organisms and are promising candidates to treat infections caused by pathogenic bacteria to animals and humans. AMPs also display anticancer activities because of their ability to inactivate a wide range of cancer cells. Cancer remains a cause of high morbidity and mortality worldwide. Therefore, the development of methods for its control is desirable. Attractive alternatives include plant AMP thionins, defensins, and cyclotides, which have anticancer activities. Here, we provide an overview of plant AMPs anticancer activities, with an emphasis on their mode of action, their selectivity, and their efficacy.
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36
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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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37
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Reinwarth M, Avrutina O, Fabritz S, Kolmar H. Fragmentation follows structure: top-down mass spectrometry elucidates the topology of engineered cystine-knot miniproteins. PLoS One 2014; 9:e108626. [PMID: 25303319 PMCID: PMC4193770 DOI: 10.1371/journal.pone.0108626] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/02/2014] [Indexed: 12/21/2022] Open
Abstract
Over the last decades the field of pharmaceutically relevant peptides has enormously expanded. Among them, several peptide families exist that contain three or more disulfide bonds. In this context, elucidation of the disulfide patterns is extremely important as these motifs are often prerequisites for folding, stability, and activity. An example of this structure-determining pattern is a cystine knot which comprises three constrained disulfide bonds and represents a core element in a vast number of mechanically interlocked peptidic structures possessing different biological activities. Herein, we present our studies on disulfide pattern determination and structure elucidation of cystine-knot miniproteins derived from Momordica cochinchinensis peptide MCoTI-II, which act as potent inhibitors of human matriptase-1. A top-down mass spectrometric analysis of the oxidised and bioactive peptides is described. Following the detailed sequencing of the peptide backbone, interpretation of the MS(3) spectra allowed for the verification of the knotted topology of the examined miniproteins. Moreover, we found that the fragmentation pattern depends on the knottin's folding state, hence, tertiary structure, which to our knowledge has not been described for a top-down MS approach before.
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Affiliation(s)
- Michael Reinwarth
- Institute of Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Darmstadt, Germany
| | - Olga Avrutina
- Institute of Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Darmstadt, Germany
| | | | - Harald Kolmar
- Institute of Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Darmstadt, Germany
- * E-mail: (SF); (HK)
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38
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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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39
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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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40
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Wang CK, Gruber CW, Cemazar M, Siatskas C, Tagore P, Payne N, Sun G, Wang S, Bernard CC, Craik DJ. Molecular grafting onto a stable framework yields novel cyclic peptides for the treatment of multiple sclerosis. ACS Chem Biol 2014; 9:156-63. [PMID: 24147816 PMCID: PMC3898541 DOI: 10.1021/cb400548s] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
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Multiple sclerosis (MS) is an inflammatory
disease of the central
nervous system (CNS) and is characterized by the destruction of myelin
and axons leading to progressive disability. Peptide epitopes from
CNS proteins, such as myelin oligodendrocyte glycoprotein (MOG), possess
promising immunoregulatory potential for treating MS; however, their
instability and poor bioavailability is a major impediment for their
use clinically. To overcome this problem, we used molecular grafting
to incorporate peptide sequences from the MOG35–55 epitope onto a cyclotide, which is a macrocyclic peptide scaffold
that has been shown to be intrinsically stable. Using this approach,
we designed novel cyclic peptides that retained the structure and
stability of the parent scaffold. One of the grafted peptides, MOG3,
displayed potent ability to prevent disease development in a mouse
model of MS. These results demonstrate the potential of bioengineered
cyclic peptides for the treatment of MS.
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Affiliation(s)
- Conan K. Wang
- Institute
for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
| | - Christian W. Gruber
- Institute
for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
- Center
for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna 1090, Austria
| | - Maša Cemazar
- Institute
for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
| | - Christopher Siatskas
- Multiple
Sclerosis Research Group, Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Prascilla Tagore
- Institute
for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
| | - Natalie Payne
- Multiple
Sclerosis Research Group, Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Guizhi Sun
- Multiple
Sclerosis Research Group, Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Shunhe Wang
- Multiple
Sclerosis Research Group, Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Claude C. Bernard
- Multiple
Sclerosis Research Group, Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - David J. Craik
- Institute
for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
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41
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Glotzbach B, Reinwarth M, Weber N, Fabritz S, Tomaszowski M, Fittler H, Christmann A, Avrutina O, Kolmar H. Combinatorial optimization of cystine-knot peptides towards high-affinity inhibitors of human matriptase-1. PLoS One 2013; 8:e76956. [PMID: 24146945 PMCID: PMC3795654 DOI: 10.1371/journal.pone.0076956] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 08/27/2013] [Indexed: 12/02/2022] Open
Abstract
Cystine-knot miniproteins define a class of bioactive molecules with several thousand natural members. Their eponymous motif comprises a rigid structured core formed by six disulfide-connected cysteine residues, which accounts for its exceptional stability towards thermic or proteolytic degradation. Since they display a remarkable sequence tolerance within their disulfide-connected loops, these molecules are considered promising frameworks for peptide-based pharmaceuticals. Natural open-chain cystine-knot trypsin inhibitors of the MCoTI (Momordica cochinchinensis trypsin inhibitor) and SOTI (Spinacia oleracea trypsin inhibitor) families served as starting points for the generation of inhibitors of matriptase-1, a type II transmembrane serine protease with possible clinical relevance in cancer and arthritic therapy. Yeast surface-displayed libraries of miniproteins were used to select unique and potent matriptase-1 inhibitors. To this end, a knowledge-based library design was applied that makes use of detailed information on binding and folding behavior of cystine-knot peptides. Five inhibitor variants, four of the MCoTI family and one of the SOTI family, were identified, chemically synthesized and oxidatively folded towards the bioactive conformation. Enzyme assays revealed inhibition constants in the low nanomolar range for all candidates. One subnanomolar binder (Ki = 0.83 nM) with an inverted selectivity towards trypsin and matriptase-1 was identified.
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Affiliation(s)
- Bernhard Glotzbach
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Michael Reinwarth
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Niklas Weber
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | | | - Michael Tomaszowski
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Heiko Fittler
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Andreas Christmann
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Olga Avrutina
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Harald Kolmar
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
- * E-mail:
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42
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Novel inhibitor cystine knot peptides from Momordica charantia. PLoS One 2013; 8:e75334. [PMID: 24116036 PMCID: PMC3792974 DOI: 10.1371/journal.pone.0075334] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Accepted: 08/13/2013] [Indexed: 11/20/2022] Open
Abstract
Two new peptides, MCh-1 and MCh-2, along with three known trypsin inhibitors (MCTI-I, MCTI-II and MCTI-III), were isolated from the seeds of the tropical vine Momordica charantia. The sequences of the peptides were determined using mass spectrometry and NMR spectroscopy. Using a strategy involving partial reduction and stepwise alkylation of the peptides, followed by enzymatic digestion and tandem mass spectrometry sequencing, the disulfide connectivity of MCh-1 was elucidated to be CysI-CysIV, CysII-CysV and CysIII-CysVI. The three-dimensional structures of MCh-1 and MCh-2 were determined using NMR spectroscopy and found to contain the inhibitor cystine knot (ICK) motif. The sequences of the novel peptides differ significantly from peptides previously isolated from this plant. Therefore, this study expands the known peptide diversity in M. charantia and the range of sequences that can be accommodated by the ICK motif. Furthermore, we show that a stable two-disulfide intermediate is involved in the oxidative folding of MCh-1. This disulfide intermediate is structurally homologous to the proposed ancestral fold of ICK peptides, and provides a possible pathway for the evolution of this structural motif, which is highly prevalent in nature.
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Li H, Bowling JJ, Fronczek FR, Hong J, Jabba SV, Murray TF, Ha NC, Hamann MT, Jung JH. Asteropsin A: an unusual cystine-crosslinked peptide from porifera enhances neuronal Ca2+ influx. Biochim Biophys Acta Gen Subj 2013. [PMID: 23201194 DOI: 10.1016/j.bbagen.2012.11.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Herein we report the discovery of a cystine-crosslinked peptide from Porifera along with high-quality spatial details accompanied by the description of its unique effect on neuronal calcium influx. METHODS Asteropsin A (ASPA) was isolated from the marine sponge Asteropus sp., and its structure was independently determined using X-ray crystallography (0.87 angstroms) and solution NMR spectroscopy. RESULTS An N-terminal pyroglutamate modification, uncommon cis proline conformations, and absence of basic residues helped distinguish ASPA from other cystine-crosslinked knot peptides. ASPA enhanced Ca2+ influx in murine cerebrocortical neuron cells following the addition of the Na+ channel activator veratridine but did not modify the oscillation frequency or amplitude of neuronal Ca2+ currents alone. Allosterism at neurotoxin site 2 was not observed, suggesting an alternative to the known Na+ channel interaction. CONCLUSIONS Together with a distinct biological activity, the origin of ASPA suggests a new subclass of cystine-rich knot peptides associated with Porifera. GENERAL SIGNIFICANCE The discovery of ASPA represents a distinctive addition to an emerging subclass of cystine-crosslinked knot peptides from Porifera.
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Affiliation(s)
- Huayue Li
- College of Pharmacy, Pusan National University, Busan 609-735, Korea.
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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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Vink S, Alewood PF. Targeting voltage-gated calcium channels: developments in peptide and small-molecule inhibitors for the treatment of neuropathic pain. Br J Pharmacol 2013; 167:970-89. [PMID: 22725651 DOI: 10.1111/j.1476-5381.2012.02082.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Chronic pain affects approximately 20% of people worldwide and places a large economic and social burden on society. Despite the availability of a range of analgesics, this condition is inadequately treated, with complete alleviation of symptoms rarely occurring. In the past 30 years, the voltage-gated calcium channels (VGCCs) have been recognized as potential targets for analgesic development. Although the majority of the research has been focused on Ca(v) 2.2 in particular, other VGCC subtypes such as Ca(v) 3.2 have recently come to the forefront of analgesic research. Venom peptides from marine cone snails have been proven to be a valuable tool in neuroscience, playing a major role in the identification and characterization of VGCC subtypes and producing the first conotoxin-based drug on the market, the ω-conotoxin, ziconotide. This peptide potently and selectively inhibits Ca(v) 2.2, resulting in analgesia in chronic pain states. However, this drug is only available via intrathecal administration, and adverse effects and a narrow therapeutic window have limited its use in the clinic. Other Ca(v) 2.2 inhibitors are currently in development and offer the promise of an improved route of administration and safety profile. This review assesses the potential of targeting VGCCs for analgesic development, with a main focus on conotoxins that block Ca(v) 2.2 and the developments made to transform them into therapeutics.
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Affiliation(s)
- S Vink
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
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Conibear AC, Rosengren KJ, Daly NL, Henriques ST, Craik DJ. The cyclic cystine ladder in θ-defensins is important for structure and stability, but not antibacterial activity. J Biol Chem 2013; 288:10830-40. [PMID: 23430740 DOI: 10.1074/jbc.m113.451047] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
θ-Defensins are ribosomally synthesized cyclic peptides found in the leukocytes of some primate species and have promising applications as antimicrobial agents and scaffolds for peptide drugs. The cyclic cystine ladder motif, comprising a cyclic peptide backbone and three parallel disulfide bonds, is characteristic of θ-defensins. In this study, we explore the role of the cyclic peptide backbone and cystine ladder in the structure, stability, and activity of θ-defensins. θ-Defensin analogues with different numbers and combinations of disulfide bonds were synthesized and characterized in terms of their NMR solution structures, serum and thermal stabilities, and their antibacterial and membrane-binding activities. Whereas the structures and stabilities of the peptides were primarily dependent on the number and position of the disulfide bonds, their antibacterial and membrane-binding properties were dependent on the cyclic backbone. The results provide insights into the mechanism of action of θ-defensins and illustrate the potential of θ-defensin analogues as scaffolds for peptide drug design.
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Affiliation(s)
- Anne C Conibear
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane, Queensland 4072, Australia
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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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Göransson U, Burman R, Gunasekera S, Strömstedt AA, Rosengren KJ. Circular proteins from plants and fungi. J Biol Chem 2012; 287:27001-6. [PMID: 22700984 DOI: 10.1074/jbc.r111.300129] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Circular proteins, defined as head-to-tail cyclized polypeptides originating from ribosomal synthesis, represent a novel class of natural products attracting increasing interest. From a scientific point of view, these compounds raise questions of where and why they occur in nature and how they are formed. From a rational point of view, these proteins and their structural concept may be exploited for crop protection and novel pharmaceuticals. Here, we review the current knowledge of three protein families: cyclotides and circular sunflower trypsin inhibitors from the kingdom of plants and the Amanita toxins from fungi. A particular emphasis is placed on their biological origin, structure, and activity. In addition, the opportunity for discovery of novel circular proteins and recent insights into their mechanism of action are discussed.
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Affiliation(s)
- Ulf Göransson
- Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Centre, Uppsala University, SE-75123 Uppsala, Sweden.
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Gould A, Ji Y, Aboye TL, Camarero JA. Cyclotides, a novel ultrastable polypeptide scaffold for drug discovery. Curr Pharm Des 2012; 17:4294-307. [PMID: 22204428 DOI: 10.2174/138161211798999438] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Accepted: 09/15/2011] [Indexed: 11/22/2022]
Abstract
Cyclotides are a unique and growing family of backbone cyclized peptides that also contain a cystine knot motif built from six conserved cysteine residues. This unique circular backbone topology and knotted arrangement of three disulfide bonds makes them exceptionally stable to thermal, chemical, and enzymatic degradation compared to other peptides of similar size. Aside from the conserved residues forming the cystine knot, cyclotides have been shown to have high variability in their sequences. Consisting of over 160 known members, cyclotides have many biological activities, ranging from anti-HIV, antimicrobial, hemolytic, and uterotonic capabilities; additionally, some cyclotides have been shown to have cell penetrating properties. Originally discovered and isolated from plants, cyclotides can also be produced synthetically and recombinantly. The high sequence variability, stability, and cell penetrating properties of cyclotides make them potential scaffolds to be used to graft known active peptides or engineer peptide-based drug design. The present review reports recent findings in the biological diversity and therapeutic potential of natural and engineered cyclotides.
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Affiliation(s)
- Andrew Gould
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, USA
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Abstract
The advent of modern antibody engineering has led to numerous successes in the application of these proteins for cancer therapy in the 13 years since the first Food and Drug Administration approval, which has stimulated active interest in developing more and better drugs based on these molecules. A wide range of tools for discovering and engineering antibodies has been brought to bear on this challenge in the past two decades. Here, we summarize mechanisms of monoclonal antibody therapeutic activity, challenges to effective antibody-based treatment, existing technologies for antibody engineering, and current concepts for engineering new antibody formats and antibody alternatives as next generation biopharmaceuticals for cancer treatment.
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Affiliation(s)
- Eric T Boder
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996-2200, USA.
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