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Khalifeh-Kandy AS, Nayeri FD, Ahmadabadi M. Production of functional recombinant roseltide rT1 antimicrobial peptide in tobacco plants. J Biotechnol 2024; 381:49-56. [PMID: 38181983 DOI: 10.1016/j.jbiotec.2023.12.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 12/31/2023] [Indexed: 01/07/2024]
Abstract
Plant-derived peptides represent a promising group of natural compounds with broad industrial and pharmaceutical applications. Low-efficiency production level is the major obstacle to the commercial production of such bioactive peptides. Today, recombinant techniques have been developed for fast and cost-effective production of high-quality peptides for various applications in the chemical and food industries. The roseltide rT1 is a plant peptide with different antimicrobial properties and therapeutic applications in the prevention and treatment of inflammatory lung diseases by inhibiting human neutrophil elastases. Here, we report the expression of functional recombinant roseltide rT1 peptide in tobacco plants. Transgenic plants were generated by the Agrobacterium-mediated transformation method followed by molecular analysis of transgenic plants to demonstrate successful integration and expression of recombinant rT1 peptide. Protein extracts of transgenic plants expressing a single-copy rT1 gene showed efficient antimicrobial properties as verified by growth inhibition of different bacterial strains. Our results illustrate that plant-derived recombinant rT1 peptide is a promising alternative for rapid and cost-effective production of this important antimicrobial peptide for application in therapeutic and food industries.
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Affiliation(s)
- Amin Sahandi Khalifeh-Kandy
- Department of Biotechnology, Faculty of Agriculture, Azarbaijan Shahid Madani University, 35 km Tabriz-Maraqeh Road, Tabriz, Iran
| | - Fatemeh Dehghan Nayeri
- Department of Biotechnology, Faculty of Agriculture, Azarbaijan Shahid Madani University, 35 km Tabriz-Maraqeh Road, Tabriz, Iran.
| | - Mohammad Ahmadabadi
- Department of Biotechnology, Faculty of Agricultural and Natural Sciences, Imam Khomeini International University (IKIU), Qazvin, Iran.
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2
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Nitride C, D’Auria G, Dente A, Landolfi V, Picariello G, Mamone G, Blandino M, Romano R, Ferranti P. Tritordeum as an Innovative Alternative to Wheat: A Comparative Digestion Study on Bread. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27041308. [PMID: 35209097 PMCID: PMC8877140 DOI: 10.3390/molecules27041308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/08/2022] [Accepted: 02/13/2022] [Indexed: 11/16/2022]
Abstract
Tritordeum results from the crossbreeding of a wild barley (Hordeum chilense) species with durum wheat (Triticum turgidum spp. turgidum). This hexaploid crop exhibits agronomic and rheological characteristics like soft wheat, resulting in an innovative raw material to produce baked goods. We applied a gel-based proteomic approach on refined flours to evaluate protein expression differences among two widespread tritordeum cultivars (Aucan and Bulel) taking as the reference semolina and flour derived from a durum and a soft wheat cvs, respectively. The products of in vitro digestion of model breads were analyzed to compare bio-accessibility of nutrients and mapping tritordeum bread resistant peptides. Significant differences among the protein profiles of the four flours were highlighted by electrophoresis. The amino acid bio-accessibility and the reducing sugars of tritordeum and wheat breads were comparable. Tritordeum cvs had about 15% higher alpha-amino nitrogen released at the end of the duodenal simulated digestion than soft wheat (p < 0.05). Bulel tritordeum flour, bread and digested bread had about 55% less R5-epitopes compared to the soft wheat. Differences in protein expression found between the two tritordeum cvs reflected in diverse digestion products and allergenic and celiacogenic potential of the duodenal peptides. Proteomic studies of a larger number of tritordeum cvs may be successful in selecting those with good agronomical performances and nutritional advantages.
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Affiliation(s)
- Chiara Nitride
- Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055 Portici, Italy; (C.N.); (A.D.); (R.R.); (P.F.)
| | - Giovanni D’Auria
- Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055 Portici, Italy; (C.N.); (A.D.); (R.R.); (P.F.)
- Correspondence: ; Tel.: +39-81253-9346
| | - Andrea Dente
- Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055 Portici, Italy; (C.N.); (A.D.); (R.R.); (P.F.)
| | - Viola Landolfi
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Braccini 2, 10095 Grugliasco, Italy; (V.L.); (M.B.)
| | - Gianluca Picariello
- Institute of Food Science, National Research Council, 83100 Avellino, Italy; (G.P.); (G.M.)
| | - Gianfranco Mamone
- Institute of Food Science, National Research Council, 83100 Avellino, Italy; (G.P.); (G.M.)
| | - Massimo Blandino
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Braccini 2, 10095 Grugliasco, Italy; (V.L.); (M.B.)
| | - Raffaele Romano
- Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055 Portici, Italy; (C.N.); (A.D.); (R.R.); (P.F.)
| | - Pasquale Ferranti
- Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055 Portici, Italy; (C.N.); (A.D.); (R.R.); (P.F.)
- Institute of Food Science, National Research Council, 83100 Avellino, Italy; (G.P.); (G.M.)
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3
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Attah AF, Omobola AI, Moody JO, Sonibare MA, Adebukola OM, Onasanwo SA. Detection of cysteine-rich peptides in Tragia benthamii Baker (Euphorbiaceae) and in vivo antiinflammatory effect in a chick model. PHYSICAL SCIENCES REVIEWS 2021. [DOI: 10.1515/psr-2020-0125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Abstract
Tragia benthamii (TBM) commonly called the climbing nettle is a tropical plant claimed to have numerous anti inflammatory effects in sub Saharan African ethnomedicine which lacks scientific evidence. Aqueous extracts of TBM were further prepurified on a RP-C18 parked solid phase system to obtain 20% aqueous fraction. This fraction was enzymatically and chemically analyzed (by MALDI TOF MS and MS/MS) to contain interesting low molecular weight cysteine-rich stable peptides within the range of 2.5–3.2 KDa. The 20% aqueous fraction was further tested in vivo using carrageenan-induced foot edema (acute inflammation) in seven-day old chicks with diclofenac as reference drug. The cytotoxicity of this active fraction was investigated using the brine shrimp lethality assay. The brine shrimp cytotoxicity assay produced LC50 above 1000 μg/mL. Pretreatment with the TBM extract (30–300 mg/kg, i.p) dose dependently (P<0.01) reduced foot edema with maximal inhibition of 0.253 ± 0.180 (84.3%) at 300 mg/kg body weight, which was comparable to that of diclofenac with inhibition (P<0.05) of 0.410 ± 0.271 (74.5%) at 10 mg/kg body weight. The study has therefore shown for the first time, the detection of cysteine-rich biologically active peptides in T. benthamii and the stable peptide extracts from this ethnomedicinal plant, which is not toxic to Artemia salina, exhibits anti inflammatory activity in a chick in vivo model. This may provide scientific evidence for its use in the treatment of inflammation and pain in traditional medicine. Further in-depth vivo and in vitro studies will be required to investigate its anti inflammatory activity including effect on HUVEC-TERT, the possible inhibition of ICAM-1 surface expression and the mechanism of the anti inflammatory effect.
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Affiliation(s)
- Alfred F. Attah
- Department of Pharmacognosy and Drug Development, Faculty of Pharmaceutical Sciences , University of Ilorin , Ilorin , Nigeria
- Department of Pharmacognosy, Faculty of Pharmacy , University of Ibadan , Ibadan , Nigeria
| | - Abobarin I. Omobola
- Department of Pharmacognosy, Faculty of Pharmacy , University of Ibadan , Ibadan , Nigeria
| | - Jones O. Moody
- Department of Pharmacognosy, Faculty of Pharmacy , University of Ibadan , Ibadan , Nigeria
| | - Mubo A. Sonibare
- Department of Pharmacognosy, Faculty of Pharmacy , University of Ibadan , Ibadan , Nigeria
| | - Olubori M. Adebukola
- Department of Physiology, College of Medicine , University of Ibadan , Ibadan , Nigeria
| | - Samuel A. Onasanwo
- Department of Physiology, College of Medicine , University of Ibadan , Ibadan , Nigeria
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4
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Peck A, Yao Q, Brewster AS, Zwart PH, Heumann JM, Sauter NK, Jensen GJ. Challenges in solving structures from radiation-damaged tomograms of protein nanocrystals assessed by simulation. Acta Crystallogr D Struct Biol 2021; 77:572-586. [PMID: 33950014 PMCID: PMC8098477 DOI: 10.1107/s2059798321002369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 03/02/2021] [Indexed: 11/11/2022] Open
Abstract
Structure-determination methods are needed to resolve the atomic details that underlie protein function. X-ray crystallography has provided most of our knowledge of protein structure, but is constrained by the need for large, well ordered crystals and the loss of phase information. The rapidly developing methods of serial femtosecond crystallography, micro-electron diffraction and single-particle reconstruction circumvent the first of these limitations by enabling data collection from nanocrystals or purified proteins. However, the first two methods also suffer from the phase problem, while many proteins fall below the molecular-weight threshold required for single-particle reconstruction. Cryo-electron tomography of protein nanocrystals has the potential to overcome these obstacles of mainstream structure-determination methods. Here, a data-processing scheme is presented that combines routines from X-ray crystallography and new algorithms that have been developed to solve structures from tomograms of nanocrystals. This pipeline handles image-processing challenges specific to tomographic sampling of periodic specimens and is validated using simulated crystals. The tolerance of this workflow to the effects of radiation damage is also assessed. The simulations indicate a trade-off between a wider tilt range to facilitate merging data from multiple tomograms and a smaller tilt increment to improve phase accuracy. Since phase errors, but not merging errors, can be overcome with additional data sets, these results recommend distributing the dose over a wide angular range rather than using a finer sampling interval to solve the protein structure.
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Affiliation(s)
- Ariana Peck
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Qing Yao
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Aaron S. Brewster
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Petrus H. Zwart
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Center for Advanced Mathematics in Energy Research Applications, Lawrence Berkeley National Laboratory, Berkeley CA 94720, USA
| | - John M. Heumann
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Nicholas K. Sauter
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Grant J. Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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5
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Parthasarathy A, Borrego EJ, Savka MA, Dobson RCJ, Hudson AO. Amino acid-derived defense metabolites from plants: A potential source to facilitate novel antimicrobial development. J Biol Chem 2021; 296:100438. [PMID: 33610552 PMCID: PMC8024917 DOI: 10.1016/j.jbc.2021.100438] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 12/23/2022] Open
Abstract
For millennia, humanity has relied on plants for its medicines, and modern pharmacology continues to reexamine and mine plant metabolites for novel compounds and to guide improvements in biological activity, bioavailability, and chemical stability. The critical problem of antibiotic resistance and increasing exposure to viral and parasitic diseases has spurred renewed interest into drug treatments for infectious diseases. In this context, an urgent revival of natural product discovery is globally underway with special attention directed toward the numerous and chemically diverse plant defensive compounds such as phytoalexins and phytoanticipins that combat herbivores, microbial pathogens, or competing plants. Moreover, advancements in “omics,” chemistry, and heterologous expression systems have facilitated the purification and characterization of plant metabolites and the identification of possible therapeutic targets. In this review, we describe several important amino acid–derived classes of plant defensive compounds, including antimicrobial peptides (e.g., defensins, thionins, and knottins), alkaloids, nonproteogenic amino acids, and phenylpropanoids as potential drug leads, examining their mechanisms of action, therapeutic targets, and structure–function relationships. Given their potent antibacterial, antifungal, antiparasitic, and antiviral properties, which can be superior to existing drugs, phytoalexins and phytoanticipins are an excellent resource to facilitate the rational design and development of antimicrobial drugs.
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Affiliation(s)
- Anutthaman Parthasarathy
- Rochester Institute of Technology, Thomas H. Gosnell School of Life Sciences, Rochester, New York, USA
| | - Eli J Borrego
- Rochester Institute of Technology, Thomas H. Gosnell School of Life Sciences, Rochester, New York, USA
| | - Michael A Savka
- Rochester Institute of Technology, Thomas H. Gosnell School of Life Sciences, Rochester, New York, USA
| | - Renwick C J Dobson
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand; Bio21 Molecular Science and Biotechnology Institute, Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia
| | - André O Hudson
- Rochester Institute of Technology, Thomas H. Gosnell School of Life Sciences, Rochester, New York, USA.
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6
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Identification and characterization of a wolfberry carboxypeptidase inhibitor from Lycium barbarum. Food Chem 2021; 351:129338. [PMID: 33647700 DOI: 10.1016/j.foodchem.2021.129338] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 01/22/2021] [Accepted: 02/06/2021] [Indexed: 01/13/2023]
Abstract
Hyperstable cysteine-rich peptides (CRPs) represent an underexplored superfamily of bioactives in functional foods. An example is wolfberry of the Lycium barbarum family. Previously, we discovered a CRP, designated α-lybatide, from L. barbarum bark. Herein, we report the discovery of β-lybatide, a novel carboxypeptidase inhibitor belonging to a different CRP family from the wolfberry plant. Proteomic and transcriptomic analyses showed that β-lybatide contains 36 amino acids with six cysteine residues. NMR spectroscopy revealed that β-lybatide displays a knottin-like structure that renders it highly resistant to thermal, chemical and enzymatic degradation, conditions important for keeping its structural integrity in gastrointestinal tract. Biochemical assays showed that β-lybatide is a potent carboxypeptidase inhibitor which could contribute to the wolfberry biological activities. Bioinformatics analysis revealed an additional 49 β-lybatide-like plant carboxypeptidase inhibitors. Together, our results show that β-lybatide is the first and the smallest plant-derived hyperstable carboxypeptidase inhibitor discovered from a functional food.
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7
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Juhász J, Gáspári Z, Pongor S. Structure and Oxidative Folding of AAI, the Major Alfa-Amylase Inhibitor From Amaranth Seeds. Front Chem 2020; 8:180. [PMID: 32257998 PMCID: PMC7090091 DOI: 10.3389/fchem.2020.00180] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 02/26/2020] [Indexed: 11/30/2022] Open
Abstract
AAI, the major alpha-amylase inhibitor (AAI) present in the seeds of the Mexican crop plant Amaranthus hypocondriacus is a 32-residue-long polypeptide with three disulfide bridges. Its structure is most closely related to the plant amylase inhibitor subfamily of knottins characterized by a topological knot formed by one disulfide bridge threading through a loop formed by the peptide chain as well as a short three-stranded beta sandwich core. AAI is specific against insect amylases and does not act on corresponding human or mammalian enzymes. It was found that the oxidative folding of AAI seems to follow a hirudine-like pathway with many non-native intermediates, but notably it proceeds through a major folding intermediate (MFI) that contains a vicinal disulfide bridge. Based on a review of the pertinent literature, the known vicinal disulfides in native proteins as well as well as the network of disulfide interchanges, we propose that MFI is a kinetic trap corresponding to a compact molten globule-like state which constrains the peptide chain to a smaller number of conformations that in turn can be rapidly funneled toward the native state.
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Affiliation(s)
- János Juhász
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary.,3in-PPCU Research Group, Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Esztergom, Hungary
| | - Zoltán Gáspári
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Sándor Pongor
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
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8
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Shen Y, Xu L, Huang J, Serra A, Yang H, Tam JP. Potentides: New Cysteine-Rich Peptides with Unusual Disulfide Connectivity from Potentilla anserina. Chembiochem 2019; 20:1995-2004. [PMID: 30927482 DOI: 10.1002/cbic.201900127] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Indexed: 11/06/2022]
Abstract
Cysteine-rich peptides (CRPs), which are disulfide-constrained peptides with 3 to 5 disulfide bonds and molecular weights of 2 to 6 kDa, are generally hyperstable and resistant to thermal, chemical, and enzymatic degradation. Herein, the discovery and characterization of a novel suite of CRPs, collectively named potentides pA1-pA16 from the root of the medicinal herb Potentilla anserina L, are described. Through a combination of proteomic and transcriptomic methods, it is shown that 35-residue potentide pA3, which is the most abundant member of potentides, exhibits high stability against heat, acidic, and proteolytic degradation. Transcriptomic analysis revealed that potentide precursor sequences contained four tandem repeats in the mature domain, which is the first report on tandem repeats being found in the Rosaceae family. Disulfide mapping showed that potentide pA3 displayed a novel disulfide connectivity of C1-C3, C2-C6, and C4-C5; a cystine motif that has not been reported in plant CRPs. Transcriptomic data mining and a neighbor-joining clustering analysis revealed 56 potentide homologues and their distribution in the families of Rosaceae and Ranunculaceae in angiosperm. Altogether, these results reveal a new plant CRP structure with an unusual cystine connectivity. Additionally, this study expands the families and structure diversity of CRPs as potentially active peptide pharmaceuticals.
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Affiliation(s)
- Yuping Shen
- Department of Pharmaceutics, School of Pharmacy, Jiangsu University, 301 Xuefu Road, Zhenjiang, 212013, P.R. China.,School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
| | - Lili Xu
- Department of Pharmaceutics, School of Pharmacy, Jiangsu University, 301 Xuefu Road, Zhenjiang, 212013, P.R. China
| | - Jiayi Huang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
| | - Aida Serra
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
| | - Huan Yang
- Department of Pharmaceutics, School of Pharmacy, Jiangsu University, 301 Xuefu Road, Zhenjiang, 212013, P.R. China
| | - James P Tam
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
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Kam A, Loo S, Dutta B, Sze SK, Tam JP. Plant-derived mitochondria-targeting cysteine-rich peptide modulates cellular bioenergetics. J Biol Chem 2019; 294:4000-4011. [PMID: 30674551 PMCID: PMC6422099 DOI: 10.1074/jbc.ra118.006693] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/07/2019] [Indexed: 12/16/2022] Open
Abstract
Mitochondria are attractive therapeutic targets for developing agents to delay age-related frailty and diseases. However, few promising leads have been identified from natural products. Previously, we identified roseltide rT1, a hyperstable 27-residue cysteine-rich peptide from Hibiscus sabdariffa, as a knottin-type neutrophil elastase inhibitor. Here, we show that roseltide rT1 is also a cell-penetrating, mitochondria-targeting peptide that increases ATP production. Results from flow cytometry, live-cell imaging, pulldown assays, and genetically-modified cell lines supported that roseltide rT1 enters cells via glycosaminoglycan-dependent endocytosis, and enters the mitochondria through TOM20, a mitochondrial protein import receptor. We further showed that roseltide rT1 increases cellular ATP production via mitochondrial membrane hyperpolarization. Using biotinylated roseltide rT1 for target identification and proteomic analysis, we showed that human mitochondrial membrane ATP synthase subunit O is an intramitochondrial target. Collectively, these data support our discovery that roseltide rT1 is a first-in-class mitochondria-targeting, cysteine-rich peptide with potentials to be developed into tools to further our understanding of mitochrondria-related diseases.
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Affiliation(s)
- Antony Kam
- From the School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - Shining Loo
- From the School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - Bamaprasad Dutta
- From the School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - Siu Kwan Sze
- From the School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - James P Tam
- From the School of Biological Sciences, Nanyang Technological University, 637551 Singapore
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10
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A structural perspective of plant antimicrobial peptides. Biochem J 2018; 475:3359-3375. [PMID: 30413680 DOI: 10.1042/bcj20180213] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 10/12/2018] [Accepted: 10/14/2018] [Indexed: 12/26/2022]
Abstract
Among the numerous strategies plants have developed to fend off enemy attack, antimicrobial peptides (AMPs) stand out as one of the most prominent defensive barriers that grant direct and durable resistance against a wide range of pests and pathogens. These small proteins are characterized by a compact structure and an overall positive charge. AMPs have an ancient origin and widespread occurrence in the plant kingdom but show an unusually high degree of variation in their amino acid sequences. Interestingly, there is a strikingly conserved topology among the plant AMP families, suggesting that the defensive properties of these peptides are not determined by their primary sequences but rather by their tridimensional structure. To explore and expand this idea, we here discuss the role of AMPs for plant defense from a structural perspective. We show how specific structural properties, such as length, charge, hydrophobicity, polar angle and conformation, are essential for plant AMPs to act as a chemical shield that hinders enemy attack. Knowledge on the topology of these peptides is facilitating the isolation, classification and even structural redesign of AMPs, thus allowing scientists to develop new peptides with multiple agronomical and pharmacological potential.
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11
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Ginsentides: Cysteine and Glycine-rich Peptides from the Ginseng Family with Unusual Disulfide Connectivity. Sci Rep 2018; 8:16201. [PMID: 30385768 PMCID: PMC6212409 DOI: 10.1038/s41598-018-33894-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 10/08/2018] [Indexed: 12/21/2022] Open
Abstract
Ginseng, a popular and valuable traditional medicine, has been used for centuries to maintain health and treat disease. Here we report the discovery and characterization of ginsentides, a novel family of cysteine and glycine-rich peptides derived from the three most widely-used ginseng species: Panax ginseng, Panax quinquefolius, and Panax notoginseng. Using proteomic and transcriptomic methods, we identified 14 ginsentides, TP1-TP14 which consist of 31-33 amino acids and whose expression profiles are species- and tissues-dependent. Ginsentides have an eight-cysteine motif typical of the eight-cysteine-hevein-like peptides (8C-HLP) commonly found in medicinal herbs, but lack a chitin-binding domain. Transcriptomic analysis showed that the three-domain biosynthetic precursors of ginsentides differ from known 8C-HLP precursors in architecture and the absence of a C-terminal protein-cargo domain. A database search revealed an additional 50 ginsentide-like precursors from both gymnosperms and angiosperms. Disulfide mapping and structure determination of the ginsentide TP1 revealed a novel disulfide connectivity that differs from the 8C-HLPs. The structure of ginsentide TP1 is highly compact, with the N- and C-termini topologically fixed by disulfide bonds to form a pseudocyclic structure that confers resistance to heat, proteolysis, and acid and serum-mediated degradation. Together, our results expand the chemical space of natural products found in ginseng and highlight the occurrence, distribution, disulfide connectivity, and precursor architectures of cysteine- and glycine-rich ginsentides as a class of novel non-chitin-binding, non-cargo-carrying 8C-HLPs.
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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: 76] [Impact Index Per Article: 12.7] [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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Ochiai A, Ogawa K, Fukuda M, Ohori M, Kanaoka T, Tanaka T, Taniguchi M, Sagehashi Y. Rice Defensin OsAFP1 is a New Drug Candidate against Human Pathogenic Fungi. Sci Rep 2018; 8:11434. [PMID: 30061724 PMCID: PMC6065317 DOI: 10.1038/s41598-018-29715-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/17/2018] [Indexed: 12/28/2022] Open
Abstract
Fungal infections, such as candidiasis and aspergillosis, are some of the most frequent infections in humans. Although antifungal drugs are available for the treatment of these infections, antifungal agents with new mechanisms of action should be developed because of the increasing incidence of drug-resistant pathogens in recent years. In this study, a basic functional analysis of rice defensin OsAFP1, a novel antifungal drug candidate, was conducted. OsAFP1 exerted fungicidal activity against Candida albicans, the most common pathogenic fungus in humans, at 4 μM concentration, but it did not inhibit the growth of human pathogenic bacteria. In addition, OsAFP1 retained structural stability after heat treatment at 100 °C for 10 min and after serum treatment at 37 °C for 24 h. A propidium iodide (PI) uptake assay and mutational analysis revealed that amino acid residues within the C-terminal γ-core motif of OsAFP1, particularly Leu-39 and Lys-41, play an important role in its antifungal activity. Further, PI uptake and apoptosis assays suggested that OsAFP1 exerts its antifungal activity by inducing apoptosis of target cells. Immunohistochemistry showed that the OsAFP1 target molecule was located in the cell wall. These findings indicate that OsAFP1 may be developed into a potent antifungal drug.
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Affiliation(s)
- Akihito Ochiai
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan.
| | - Kodai Ogawa
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan
| | - Minami Fukuda
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan
| | - Masahiro Ohori
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan
| | - Takumi Kanaoka
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan
| | - Takaaki Tanaka
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan
| | - Masayuki Taniguchi
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan
| | - Yoshiyuki Sagehashi
- Hokkaido Agricultural Research Center, National Agriculture and Food Research Organization (NARO), Hokkaido, Japan.
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Kumari G, Wong KH, Serra A, Shin J, Yoon HS, Sze SK, Tam JP. Molecular diversity and function of jasmintides from Jasminum sambac. BMC PLANT BIOLOGY 2018; 18:144. [PMID: 29996766 PMCID: PMC6042386 DOI: 10.1186/s12870-018-1361-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/02/2018] [Indexed: 06/01/2023]
Abstract
BACKGROUND Jasmintides jS1 and jS2 from Jasminum sambac were previously identified as a novel family of cysteine-rich peptides (CRPs) with an unusual disulfide connectivity. However, very little else is known about jasmintides, particularly their molecular diversity and functions. Here, we report the discovery and characterization of a novel suite of jasmintides from J. sambac using transcriptomic, peptidomic, structural and functional tools. RESULTS Transcriptomic analysis of leaves, flowers and roots revealed 14 unique jasmintide precursors, all of which possess a three-domain architecture comprising a signal peptide, a pro-domain and a mature jasmintide domain. Peptidomic analysis, using fractionated mixtures of jasmintides and chemical derivatization of cysteine to pseudolysine, trypsin digestion and MS/MS sequencing, revealed an additional 86 jasmintides, some of which were post-translationally modified. NMR analysis showed that jasmintide jS3 has three anti-parallel β-strands with a three-disulfide connectivity of CysI-CysV, CysII-CysIV and CysIII-CysVI, which is similar to jasmintide jS1. Jasmintide jS3 was able to withstand thermal, acidic and enzymatic degradation and, importantly, exhibited antifeedant activity against mealworm Tenebrio molitor. CONCLUSION Together, this study expands the existing library of jasmintides and furthers our understanding of the molecular diversity and cystine framework of CRPs as scaffolds and tools for engineering peptides targeting pests.
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Affiliation(s)
- Geeta Kumari
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
| | - Ka Ho Wong
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
| | - Aida Serra
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
| | - Joon Shin
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
| | - Ho Sup Yoon
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
| | - Siu Kwan Sze
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
| | - James P. Tam
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
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15
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Loo S, Kam A, Xiao T, Tam JP. Bleogens: Cactus-Derived Anti-Candida Cysteine-Rich Peptides with Three Different Precursor Arrangements. FRONTIERS IN PLANT SCIENCE 2017; 8:2162. [PMID: 29312404 PMCID: PMC5743680 DOI: 10.3389/fpls.2017.02162] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 12/07/2017] [Indexed: 05/23/2023]
Abstract
Cysteine-rich peptides (CRPs) play important host-defense roles in plants. However, information concerning CRPs in the Cactaceae (cactus) family is limited, with only a single cactus-derived CRP described to date. Here, we report the identification of 15 novel CRPs with three different precursor architectures, bleogens pB1-15 from Pereskia bleo of the Cactaceae family. By combining proteomic and transcriptomic methods, we showed that the prototype, bleogen pB1, contained 36 amino acid residues, a six-cysteine motif typical of the six-cysteine-hevein-like peptide (6C-HLP) family, and a type I two-domain precursor consisting of an endoplasmic reticulum (ER) and a mature domain. In contrast, the precursors of the other 14 bleogens contained a type II three-domain architecture with a propeptide domain inserted between the ER and the mature bleogen domain. Four of these 14 bleogens display a third type of architecture with a tandemly repeating bleogen domain. A search of the Onekp database revealed that <1% plant species possess three different precursor architectures for the biosynthesis of 6C-HLPs, including Lophophora williamsii, Pereskia aculeate, Portulaca cryptopetala, Portulaca oleracea, Portulaca suffruticosa, and Talinum sp. NMR analysis confirmed that bleogen pB1 has cystine-knot disulfide connectivity as well as a two-beta-sheet and a four-loop structural fold that is similar to other 6C-HLPs. Sequence analysis, structural studies, and in silico modeling revealed that bleogen pB1 has a cation-polar-cation motif, a signature heparin-binding motif that was confirmed by heparin affinity chromatography. Cell-based assays showed that bleogen pB1 is non-toxic to mammalian cells but functions as an anti-Candida peptide. Taken together, our findings provide insight into the occurrence, functions and precursor architectures of CRPs in the cactus family.
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16
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Tan WL, Wong KH, Lei J, Sakai N, Tan HW, Hilgenfeld R, Tam JP. Lybatides from Lycium barbarum Contain An Unusual Cystine-stapled Helical Peptide Scaffold. Sci Rep 2017; 7:5194. [PMID: 28701689 PMCID: PMC5507927 DOI: 10.1038/s41598-017-05037-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/22/2017] [Indexed: 12/27/2022] Open
Abstract
Cysteine-rich peptides (CRPs) of 2–6 kDa are generally thermally and proteolytically stable because of their multiple cross-bracing disulfide bonds. Here, we report the discovery and characterization of two novel cystine-stapled CRPs, designated lybatide 1 and 2 (lyba1 and lyba2), from the cortex of Lycium barbarum root. Lybatides, 32 to 33 amino acids in length, are hyperstable and display a novel disulfide connectivity with a cysteine motif of C-C-C-C-CC-CC which contains two pairs of adjacent cysteines (-CC-CC). X-ray structure analysis revealed the presence of a single cystine-stabilized (α + π)-helix in lyba2, a rare feature of CRPs. Together, our results suggest that lybatides, one of the smallest four-disulfide-constrained plant CRPs, is a new family of CRPs. Additionally, this study provides new insights into the molecular diversity of plant cysteine-rich peptides and the unusual lybatide scaffold could be developed as a useful template for peptide engineering and therapeutic development.
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Affiliation(s)
- Wei Liang Tan
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Ka H Wong
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Jian Lei
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany.,German Center for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems Site, University of Lübeck, Lübeck, Germany
| | - Naoki Sakai
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany
| | - Hong Wei Tan
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Rolf Hilgenfeld
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany.,German Center for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems Site, University of Lübeck, Lübeck, Germany
| | - James P Tam
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
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17
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Kasar SS, Marathe KR, Bhide AJ, Herwade AP, Giri AP, Maheshwari VL, Pawar PK. A glycoprotein α-amylase inhibitor from Withania somnifera differentially inhibits various α-amylases and affects the growth and development of Tribolium castaneum. PEST MANAGEMENT SCIENCE 2017; 73:1382-1390. [PMID: 27770482 DOI: 10.1002/ps.4467] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/07/2016] [Accepted: 10/18/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Identification and characterisation of plant defensive molecules enrich our resources to design crop protection strategies. In particular, plant-derived proteinaceous inhibitor(s) of insect digestive enzymes appear to be a safe, sustainable and attractive option. RESULTS A glycoprotein having non-competitive α-amylase inhibitory activity with a molecular weight of 8.3 kDa was isolated and purified from seeds of Withania somnifera α-amylase inhibitor (WSAI). Its mass spectrometry analysis revealed 59% sequence coverage with Wrightide II-type α-amylase inhibitor from Wrightia religiosa. A dose-dependent inhibition of α-amylases from Aspergillus oryzae, Bacillus subtilis, Helicoverpa armigera and Tribolium castaneum was recorded. Interestingly, WSAI did not inhibit human salivary α-amylase significantly. When adults of T. castaneum were fed with WSAI (1.6 mg g-1 ), decrease in consumption, growth and efficiency of conversion of ingested food was evident, along with over fourfold increases in feeding deterrence index. A decline in larval residual α-amylase activity after feeding of WSAI resulted in a reduction in longevity of T. castaneum. CONCLUSION The study reflects the significance of WSAI in affecting the overall growth and development of T. castaneum. Pre- and post-harvest pest resistive capability makes WSAI a potential candidate for insect pest management. Further, the effectiveness of this inhibitor could be explored either in formulations or through a transgenic approach. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Sainath S Kasar
- Department of Biochemistry, Shivaji University, Kolhapur, Maharashtra, India
- Department of Biochemistry, School of Life Sciences, North Maharashtra University, Jalgaon, Maharashtra, India
| | - Kiran R Marathe
- Department of Biochemistry, School of Life Sciences, North Maharashtra University, Jalgaon, Maharashtra, India
| | - Amey J Bhide
- Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, Maharashtra, India
| | - Abhijeet P Herwade
- Department of Biotechnology, Shivaji University, Kolhapur, Maharashtra, India
| | - Ashok P Giri
- Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, Maharashtra, India
| | - Vijay L Maheshwari
- Department of Biochemistry, School of Life Sciences, North Maharashtra University, Jalgaon, Maharashtra, India
| | - Pankaj K Pawar
- Department of Biochemistry, Shivaji University, Kolhapur, Maharashtra, India
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18
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Bhide AJ, Channale SM, Yadav Y, Bhattacharjee K, Pawar PK, Maheshwari VL, Gupta VS, Ramasamy S, Giri AP. Genomic and functional characterization of coleopteran insect-specific α-amylase inhibitor gene from Amaranthus species. PLANT MOLECULAR BIOLOGY 2017; 94:319-332. [PMID: 28405784 DOI: 10.1007/s11103-017-0609-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 03/31/2017] [Indexed: 06/07/2023]
Abstract
The smallest 32 amino acid α-amylase inhibitor from Amaranthus hypochondriacus (AAI) is reported. The complete gene of pre-protein (AhAI) encoding a 26 amino acid (aa) signal peptide followed by the 43 aa region and the previously identified 32 aa peptide was cloned successfully. Three cysteine residues and one disulfide bond conserved within known α-amylase inhibitors were present in AhAI. Identical genomic and open reading frame was found to be present in close relatives of A. hypochondriacus namely Amaranthus paniculatus, Achyranthes aspera and Celosia argentea. Interestingly, the 3'UTR of AhAI varied in these species. The highest expression of AhAI was observed in A. hypochondriacus inflorescence; however, it was not detected in the seed. We hypothesized that the inhibitor expressed in leaves and inflorescence might be transported to the seeds. Sub-cellular localization studies clearly indicated the involvement of AhAI signal peptide in extracellular secretion. Full length rAhAI showed differential inhibition against α-amylases from human, insects, fungi and bacteria. Particularly, α-amylases from Helicoverpa armigera (Lepidoptera) were not inhibited by AhAI while Tribolium castaneum and Callosobruchus chinensis (Coleoptera) α-amylases were completely inhibited. Molecular docking of AhAI revealed tighter interactions with active site residues of T. castaneum α-amylase compared to C. chinensis α-amylase, which could be the rationale behind the disparity in their IC50. Normal growth, development and adult emergence of C. chinensis were hampered after feeding on rAhAI. Altogether, the ability of AhAI to affect the growth of C. chinensis demonstrated its potential as an efficient bio-control agent, especially against stored grain pests.
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Affiliation(s)
- Amey J Bhide
- Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India
| | - Sonal M Channale
- Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India
| | - Yashpal Yadav
- Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India
| | - Kabita Bhattacharjee
- Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India
| | - Pankaj K Pawar
- Department of Biochemistry, Shivaji University, Kolhapur, 416 004, India
| | - V L Maheshwari
- School of Life Sciences, North Maharashtra University, Jalgaon, 425 001, India
| | - Vidya S Gupta
- Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India
| | - Sureshkumar Ramasamy
- Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India
| | - Ashok P Giri
- Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India.
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19
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Kini SG, Wong KH, Tan WL, Xiao T, Tam JP. Morintides: cargo-free chitin-binding peptides from Moringa oleifera. BMC PLANT BIOLOGY 2017; 17:68. [PMID: 28359256 PMCID: PMC5374622 DOI: 10.1186/s12870-017-1014-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/17/2017] [Indexed: 05/11/2023]
Abstract
BACKGROUND Hevein-like peptides are a family of cysteine-rich and chitin-binding peptides consisting of 29-45 amino acids. Their chitin-binding property is essential for plant defense against fungi. Based on the number of cysteine residues in their sequences, they are divided into three sub-families: 6C-, 8C- and 10C-hevein-like peptides. All three subfamilies contain a three-domain precursor comprising a signal peptide, a mature hevein-like peptide and a C-terminal domain comprising a hinge region with protein cargo in 8C- and 10C-hevein-like peptides. RESULTS Here we report the isolation and characterization of two novel 8C-hevein-like peptides, designated morintides (mO1 and mO2), from the drumstick tree Moringa oleifera, a drought-resistant tree belonging to the Moringaceae family. Proteomic analysis revealed that morintides comprise 44 amino acid residues and are rich in cysteine, glycine and hydrophilic amino acid residues such as asparagine and glutamine. Morintides are resistant to thermal and enzymatic degradation, able to bind to chitin and inhibit the growth of phyto-pathogenic fungi. Transcriptomic analysis showed that they contain a three-domain precursor comprising an endoplasmic reticulum (ER) signal sequence, a mature peptide domain and a C-terminal domain. A striking feature distinguishing morintides from other 8C-hevein-like peptides is a short and protein-cargo-free C-terminal domain. Previously, a similar protein-cargo-free C-terminal domain has been observed only in ginkgotides, the 8C-hevein-like peptides from a gymnosperm Ginkgo biloba. Thus, morintides, with a cargo-free C-terminal domain, are a stand-alone class of 8C-hevein-like peptides from angiosperms. CONCLUSIONS Our results expand the existing library of hevein-like peptides and shed light on molecular diversity within the hevein-like peptide family. Our work also sheds light on the anti-fungal activity and stability of 8C-hevein-like peptides.
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Affiliation(s)
- Shruthi G. Kini
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Ka H. Wong
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Wei Liang Tan
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Tianshu Xiao
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - James P. Tam
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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20
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Molesini B, Treggiari D, Dalbeni A, Minuz P, Pandolfini T. Plant cystine-knot peptides: pharmacological perspectives. Br J Clin Pharmacol 2017; 83:63-70. [PMID: 26987851 PMCID: PMC5338163 DOI: 10.1111/bcp.12932] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/07/2016] [Accepted: 03/09/2016] [Indexed: 12/29/2022] Open
Abstract
Cystine-knot miniproteins are a class of 30-50 amino acid long peptides widespread in eukaryotic organisms. Due to their very peculiar three-dimensional structure, they exhibit high resistance to heat and peptidase attack. The cystine-knot peptides are well represented in several plant species including medicinal herbs and crops. The pharmacological interest in plant cystine-knot peptides derives from their broad biological activities, mainly cytotoxic, antimicrobial and peptidase inhibitory and in the possibility to engineer them to incorporate pharmacophoric information for oral delivery or disease biomonitoring. The mechanisms of action of plant cystine-knot peptides are still largely unknown, although the capacity to interfere with plasma membranes seems a feature common to several cystine-knot peptides. In some cases, such as potato carboxypetidase inhibitor (PCI) and tomato cystine-knot miniproteins (TCMPs), the cystine-knot peptides target human growth factor receptors either by acting as growth factor antagonist or by altering their signal transduction pathway. The possibility to identify specific molecular targets of plant cystine-knot peptides in human cells opens novel possibilities for the pharmacological use of these peptides besides their use as scaffold to develop stable disease molecular markers and therapeutic agents.
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Affiliation(s)
| | - Davide Treggiari
- Department of Medicine, Section of Internal MedicineUniversity of VeronaVeronaItaly
| | - Andrea Dalbeni
- Department of Medicine, Section of Internal MedicineUniversity of VeronaVeronaItaly
| | - Pietro Minuz
- Department of Medicine, Section of Internal MedicineUniversity of VeronaVeronaItaly
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21
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Wong KH, Tan WL, Kini SG, Xiao T, Serra A, Sze SK, Tam JP. Vaccatides: Antifungal Glutamine-Rich Hevein-Like Peptides from Vaccaria hispanica. FRONTIERS IN PLANT SCIENCE 2017; 8:1100. [PMID: 28680440 PMCID: PMC5478723 DOI: 10.3389/fpls.2017.01100] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 06/07/2017] [Indexed: 05/22/2023]
Abstract
Hevein and hevein-like peptides are disulfide-constrained chitin-binding cysteine-rich peptides. They are divided into three subfamilies, 6C-, 8C-, and 10C-hevein-like peptides, based on the number of cysteine residues. In addition, hevein-like peptides can exist in two forms, short and long. The long C-terminal form found in hevein and 10C-hevein-like peptides contain a C-terminal protein cargo. In contrast, the short form without a protein cargo is found in all three subfamilies. Here, we report the discovery and characterization of two novel glutamine-rich and protein cargo-free 8C-hevein-like peptides, vaccatides vH1 and vH2, from Vaccaria hispanica of the Caryophyllaceae family. Proteomic analyses showed that the vaccatides are 40-41 amino acids in length and contain a chitin-binding domain. NMR determination revealed that vaccatide vH2 displays a highly compact structure with a N-terminal cystine knot and an addition C-terminal disulfide bond. Stability studies showed that this compact structure renders vaccatide vH2 resistant to thermal, chemical and proteolytic degradation. The chitin-binding vH2 was shown to inhibit the mycelium growth of four phyto-pathogenic fungal strains with IC50 values in the micromolar range. Our findings show that vaccatides represent a new family of 8C-hevein-like peptides, which are protein cargo-free and glutamine-rich, characteristics that differentiate them from the prototypic hevein and the 10C-hevein-like peptides. In summary, this study enriches the existing library of hevein-like peptides and provides insight into their molecular diversity in sequence, structure and biosynthesis. Additionally, their highly disulfide-constrained structure could be used as a scaffold for developing metabolically and orally active peptidyl therapeutics.
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22
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Loo S, Kam A, Xiao T, Nguyen GKT, Liu CF, Tam JP. Identification and Characterization of Roseltide, a Knottin-type Neutrophil Elastase Inhibitor Derived from Hibiscus sabdariffa. Sci Rep 2016; 6:39401. [PMID: 27991569 PMCID: PMC5171801 DOI: 10.1038/srep39401] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 11/22/2016] [Indexed: 01/08/2023] Open
Abstract
Plant knottins are of therapeutic interest due to their high metabolic stability and inhibitory activity against proteinases involved in human diseases. The only knottin-type proteinase inhibitor against porcine pancreatic elastase was first identified from the squash family in 1989. Here, we report the identification and characterization of a knottin-type human neutrophil elastase inhibitor from Hibiscus sabdariffa of the Malvaceae family. Combining proteomic and transcriptomic methods, we identified a panel of novel cysteine-rich peptides, roseltides (rT1-rT8), which range from 27 to 39 residues with six conserved cysteine residues. The 27-residue roseltide rT1 contains a cysteine spacing and amino acid sequence that is different from the squash knottin-type elastase inhibitor. NMR analysis demonstrated that roseltide rT1 adopts a cystine-knot fold. Transcriptome analyses suggested that roseltides are bioprocessed by asparagine endopeptidases from a three-domain precursor. The cystine-knot structure of roseltide rT1 confers its high resistance against degradation by endopeptidases, 0.2 N HCl, and human serum. Roseltide rT1 was shown to inhibit human neutrophil elastase using enzymatic and pull-down assays. Additionally, roseltide rT1 ameliorates neutrophil elastase-stimulated cAMP accumulation in vitro. Taken together, our findings demonstrate that roseltide rT1 is a novel knottin-type neutrophil elastase inhibitor with therapeutic potential for neutrophil elastase associated diseases.
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Affiliation(s)
- Shining Loo
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Antony Kam
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Tianshu Xiao
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Giang K T Nguyen
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Chuan Fa Liu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - James P Tam
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
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23
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Wong KH, Tan WL, Serra A, Xiao T, Sze SK, Yang D, Tam JP. Ginkgotides: Proline-Rich Hevein-Like Peptides from Gymnosperm Ginkgo biloba. FRONTIERS IN PLANT SCIENCE 2016; 7:1639. [PMID: 27857717 PMCID: PMC5093130 DOI: 10.3389/fpls.2016.01639] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 10/18/2016] [Indexed: 05/11/2023]
Abstract
Hevein and hevein-like peptides belong to the family of chitin-binding cysteine-rich peptides. They are classified into three subfamilies, the prototypic 8C- and the 6C- and 10C-hevein-like peptides. Thus far, only five 8C-hevein-like peptides have been characterized from three angiosperms and none from gymnosperm. To determine their occurrence and distribution in the gymnosperm, Ginkgo biloba leaves were examined. Here, we report the discovery and characterization of 11 novel 8C-hevein-like peptides, namely ginkgotides gB1-gB11. Proteomic analysis showed that the ginkgotides contain 41-44 amino acids (aa), a chitin-binding domain and are Pro-rich, a distinguishing feature that differs from other hevein-like peptides. Solution NMR structure determination revealed that gB5 contains a three β-stranded structure shaped by a cystine knot with an additional disulfide bond at the C-terminus. Transcriptomic analysis showed that the ginkgotide precursors contain a three-domain architecture, comprised of a C-terminal tail (20 aa) that is significantly shorter than those of other 8C- and 10C-hevein-like peptides, which generally contain a protein cargo such as a Barwin-like protein (126 aa) or class I chitinase (254 aa). Transcriptomic data mining found an additional 48 ginkgotide homologs in 39 different gymnosperms. Phylogenetic analysis revealed that ginkgotides and their homologs belong to a new class of 8C-hevein-like peptides. Stability studies showed that ginkgotides are highly resistant to thermal, acidic and endopeptidase degradation. Ginkgotides flanked at both the N- and C-terminal ends by Pro were resistant to exopeptidase degradation by carboxypeptidase A and aminopeptidase. Antifungal assays showed that ginkgotides inhibit the hyphal growth of phyto-pathogenic fungi. Taken together, ginkgotides represent the first suite of hevein-like peptides isolated and characterized from gymnosperms. As a group, they represent a novel class of 8C-hevein-like peptides that are Pro-rich and protein-cargo free. Our findings also suggest that the ginkgotide scaffold could be useful for engineering metabolic-stable peptide therapeutics.
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Affiliation(s)
- Ka H. Wong
- School of Biological Sciences, Nanyang Technological UniversitySingapore, Singapore
| | - Wei Liang Tan
- School of Biological Sciences, Nanyang Technological UniversitySingapore, Singapore
| | - Aida Serra
- School of Biological Sciences, Nanyang Technological UniversitySingapore, Singapore
| | - Tianshu Xiao
- School of Biological Sciences, Nanyang Technological UniversitySingapore, Singapore
| | - Siu Kwan Sze
- School of Biological Sciences, Nanyang Technological UniversitySingapore, Singapore
| | - Daiwen Yang
- Department of Biological Sciences, National University of SingaporeSingapore, Singapore
| | - James P. Tam
- School of Biological Sciences, Nanyang Technological UniversitySingapore, Singapore
- *Correspondence: James P. Tam,
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Kumari G, Serra A, Shin J, Nguyen PQT, Sze SK, Yoon HS, Tam JP. Cysteine-Rich Peptide Family with Unusual Disulfide Connectivity from Jasminum sambac. JOURNAL OF NATURAL PRODUCTS 2015; 78:2791-9. [PMID: 26555361 DOI: 10.1021/acs.jnatprod.5b00762] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Cysteine-rich peptides (CRPs) are natural products with privileged peptidyl structures that represent a potentially rich source of bioactive compounds. Here, the discovery and characterization of a novel plant CRP family, jasmintides from Jasminum sambac of the Oleaceae family, are described. Two 27-amino acid jasmintides (jS1 and jS2) were identified at the gene and protein levels. Disulfide bond mapping of jS1 by mass spectrometry and its confirmation by NMR spectroscopy revealed disulfide bond connectivity of C-1-C-5, C-2-C-4, and C-3-C-6, a cystine motif that has not been reported in plant CRPs. Structural determination showed that jS1 displays a well-defined structure framed by three short antiparallel β-sheets. Genomic analysis showed that jasmintides share a three-domain precursor arrangement with a C-terminal mature domain preceded by a long pro-domain of 46 residues and an intron cleavage site between the signal sequence and pro-domain. The compact cysteine-rich structure together with an N-terminal pyroglutamic acid residue confers jasmintides high resistance to heat and enzymatic degradation, including exopeptidase treatment. Collectively, these results reveal a new plant CRP structure with an unusual cystine connectivity, which could be useful as a scaffold for designing peptide drugs.
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Affiliation(s)
- Geeta Kumari
- School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 637551, Singapore
| | - Aida Serra
- School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 637551, Singapore
| | - Joon Shin
- School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 637551, Singapore
| | - Phuong Q T Nguyen
- School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 637551, Singapore
| | - Siu Kwan Sze
- School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 637551, Singapore
| | - Ho Sup Yoon
- School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 637551, Singapore
| | - James P Tam
- School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 637551, Singapore
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Tam JP, Wang S, Wong KH, Tan WL. Antimicrobial Peptides from Plants. Pharmaceuticals (Basel) 2015; 8:711-57. [PMID: 26580629 PMCID: PMC4695807 DOI: 10.3390/ph8040711] [Citation(s) in RCA: 290] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 08/06/2015] [Accepted: 09/01/2015] [Indexed: 12/25/2022] Open
Abstract
Plant antimicrobial peptides (AMPs) have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs) of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic), lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms.
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Affiliation(s)
- James P Tam
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
| | - Shujing Wang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
- Department of Pharmacology and Pharmaceutical Sciences, School of Medicine, Tsinghua University, Beijing 100084, China.
| | - Ka H Wong
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
| | - Wei Liang Tan
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
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Nguyen PQT, Ooi JSG, Nguyen NTK, Wang S, Huang M, Liu DX, Tam JP. Antiviral Cystine Knot α-Amylase Inhibitors from Alstonia scholaris. J Biol Chem 2015; 290:31138-50. [PMID: 26546678 DOI: 10.1074/jbc.m115.654855] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Indexed: 11/06/2022] Open
Abstract
Cystine knot α-amylase inhibitors are cysteine-rich, proline-rich peptides found in the Amaranthaceae and Apocynaceae plant species. They are characterized by a pseudocyclic backbone with two to four prolines and three disulfides arranged in a knotted motif. Similar to other knottins, cystine knot α-amylase inhibitors are highly resistant to degradation by heat and protease treatments. Thus far, only the α-amylase inhibition activity has been described for members of this family. Here, we show that cystine knot α-amylase inhibitors named alstotides discovered from the Alstonia scholaris plant of the Apocynaceae family display antiviral activity. The alstotides (As1-As4) were characterized by both proteomic and genomic methods. All four alsotides are novel, heat-stable and enzyme-stable and contain 30 residues. NMR determination of As1 and As4 structures reveals their conserved structural fold and the presence of one or more cis-proline bonds, characteristics shared by other cystine knot α-amylase inhibitors. Genomic analysis showed that they contain a three-domain precursor, an arrangement common to other knottins. We also showed that alstotides are antiviral and cell-permeable to inhibit the early phase of infectious bronchitis virus and Dengue infection, in addition to their ability to inhibit α-amylase. Taken together, our results expand membership of cystine knot α-amylase inhibitors in the Apocynaceae family and their bioactivity, functional promiscuity that could be exploited as leads in developing therapeutics.
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Affiliation(s)
| | - Justin Seng Geap Ooi
- From the School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Ngan Thi Kim Nguyen
- From the School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Shujing Wang
- From the School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Mei Huang
- From the School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Ding Xiang Liu
- From the School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - James P Tam
- From the School of Biological Sciences, Nanyang Technological University, Singapore 637551
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27
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Yang H, Shen Y, Xu Y, Maqueda AS, Zheng J, Wu Q, Tam JP. A novel strategy for the discrimination of gelatinous Chinese medicines based on enzymatic digestion followed by nano-flow liquid chromatography in tandem with orbitrap mass spectrum detection. Int J Nanomedicine 2015; 10:4947-55. [PMID: 26345994 PMCID: PMC4531023 DOI: 10.2147/ijn.s82291] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Gelatinous Chinese medicines made from mammalian skin or horn or reptile shell are a very important type of animal-derived Chinese medicine. They have been extensively used either as both hemopoietic and hemostatic agents to treat vertigo, palpitation, hematuria, and insomnia in traditional Chinese medicine clinics; consumed as a popular tonic for weaker persons such as the elderly or women after giving birth; or further manufactured to health supplements for certain populations. However, they cannot be discriminated from each other by only using the routine approach in the Chinese Pharmacopoeia, as it lacks enough specificity and, consequently, and the requirements can be met even by adding assayed ingredients. In this study, our efforts to differentiate three gelatinous Chinese medicines, Asini Corii Colla, Cervi Cornus Colla, and Testudinis Carapacis ET Plastri Colla, are presented, and a novel strategy based on enzymatic digestion followed by nano-flow liquid chromatography in tandem with orbitrap mass spectrum detector analysis is proposed herein. Fourteen diagnostic fragments identified from the digests of these medicines were exclusively selected for their discrimination. By taking advantage of the favorable features of this strategy, it is feasible and convenient to identify enzymatic-digested peptides originated from signature proteins in each medicine, which thus could be employed as potential biomarkers for their form of raw medicinal material, and the pulverized and the complex especially, that being the direct basis for authentication purpose.
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Affiliation(s)
- Huan Yang
- Department of Chinese Materia Medica and Pharmacy, School of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu, People's Republic of China ; Division of Structural Biology and Biochemistry, School of Biological Sciences, College of Science, Nanyang Technological University, Singapore
| | - Yuping Shen
- Department of Chinese Materia Medica and Pharmacy, School of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu, People's Republic of China
| | - Ying Xu
- Department of Chinese Materia Medica and Pharmacy, School of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu, People's Republic of China
| | - Aida Serra Maqueda
- Division of Structural Biology and Biochemistry, School of Biological Sciences, College of Science, Nanyang Technological University, Singapore
| | - Jie Zheng
- Department of Chinese Materia Medica and Pharmacy, School of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu, People's Republic of China
| | - Qinan Wu
- Department of Chinese Medicine Authentication, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, People's Republic of China
| | - James P Tam
- Division of Structural Biology and Biochemistry, School of Biological Sciences, College of Science, Nanyang Technological University, Singapore
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Nguyen PQT, Luu TT, Bai Y, Nguyen GKT, Pervushin K, Tam JP. Allotides: Proline-Rich Cystine Knot α-Amylase Inhibitors from Allamanda cathartica. JOURNAL OF NATURAL PRODUCTS 2015; 78:695-704. [PMID: 25832441 DOI: 10.1021/np500866c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Cystine knot α-amylase inhibitors belong to a knottin family of peptidyl inhibitors of 30-32 residues and contain two to four prolines. Thus far, only four members of the group of cystine knot α-amylase inhibitors have been characterized. Herein, the discovery and characterization of five cystine knot α-amylase inhibitors, allotides C1-C5 (Ac1-Ac5) (1-5), from the medicinal plant Allamanda cathartica are reported using both proteomic and genomic methods. Proteomic analysis showed that 1-5 are 30 amino acids in length with three or four proline residues. NMR determination of 4 revealed that it has two cis- and one trans-proline residues and adopts two equally populated conformations in solution. Determination of disulfide connectivity of 2 by differential S-reduction and S-alkylation provided clues of its unfolding process. Genomic analysis showed that allotide precursors contain a three-domain arrangement commonly found in plant cystine knot peptides with conserved residues flanking the processing sites of the mature allotide domain. This work expands the number of known cystine knot α-amylase inhibitors and furthers the understanding of both the structural and biological diversity of this type of knottin family.
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Affiliation(s)
- Phuong Q T Nguyen
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Thuy T Luu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Yang Bai
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Giang K T Nguyen
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Konstantin Pervushin
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - James P Tam
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
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