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Sani MA, Rajput S, Keizer DW, Separovic F. NMR techniques for investigating antimicrobial peptides in model membranes and bacterial cells. Methods 2024; 224:10-20. [PMID: 38295893 DOI: 10.1016/j.ymeth.2024.01.012] [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: 10/31/2023] [Revised: 01/07/2024] [Accepted: 01/08/2024] [Indexed: 02/05/2024] Open
Abstract
AMPs are short, mainly cationic membrane-active peptides found in all living organism. They perform diverse roles including signaling and acting as a line of defense against bacterial infections. AMPs have been extensively investigated as templates to facilitate the development of novel antimicrobial therapeutics. Understanding the interplay between these membrane-active peptides and the lipid membranes is considered to be a significant step in elucidating the specific mechanism of action of AMPs against prokaryotic and eukaryotic cells to aid the development of new therapeutics. In this review, we have provided a brief overview of various NMR techniques commonly used for studying AMP structure and AMP-membrane interactions in model membranes and whole cells.
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Affiliation(s)
- Marc-Antoine Sani
- Bio21 Institute, University of Melbourne, Melbourne, VIC 3010, Australia.
| | - Sunnia Rajput
- Bio21 Institute, University of Melbourne, Melbourne, VIC 3010, Australia
| | - David W Keizer
- Bio21 Institute, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Frances Separovic
- Bio21 Institute, University of Melbourne, Melbourne, VIC 3010, Australia; School of Chemistry, University of Melbourne, Melbourne, VIC 3010, Australia
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Ermakova E, Makshakova O, Kurbanov R, Ibraev I, Zuev Y, Sedov I. Aggregation of Amyloidogenic Peptide Uperin-Molecular Dynamics Simulations. Molecules 2023; 28:molecules28104070. [PMID: 37241811 DOI: 10.3390/molecules28104070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/05/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
Uperin 3.5 is a remarkable natural peptide obtained from the skin of toadlets comprised of 17 amino acids which exhibits both antimicrobial and amyloidogenic properties. Molecular dynamics simulations were performed to study the β-aggregation process of uperin 3.5 as well as two of its mutants, in which the positively charged residues Arg7 and Lys8 have been replaced by alanine. All three peptides rapidly underwent spontaneous aggregation and conformational transition from random coils to beta-rich structures. The simulations reveal that the initial and essential step of the aggregation process involves peptide dimerization and the formation of small beta-sheets. A decrease in positive charge and an increase in the number of hydrophobic residues in the mutant peptides lead to an increase in the rate of their aggregation.
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Affiliation(s)
- Elena Ermakova
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, Lobachevsky Str., 2/31, Kazan 420111, Russia
| | - Olga Makshakova
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, Lobachevsky Str., 2/31, Kazan 420111, Russia
| | - Rauf Kurbanov
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, Lobachevsky Str., 2/31, Kazan 420111, Russia
| | - Ilya Ibraev
- Chemical Institute, Kazan Federal University, Kremlevskaya Str., 18, Kazan 420008, Russia
| | - Yuriy Zuev
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, Lobachevsky Str., 2/31, Kazan 420111, Russia
| | - Igor Sedov
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, Lobachevsky Str., 2/31, Kazan 420111, Russia
- Chemical Institute, Kazan Federal University, Kremlevskaya Str., 18, Kazan 420008, Russia
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Ermakova EA, Kurbanov RK. Interaction of Uperin Peptides with Model Membranes: Molecular Dynamics Study. MEMBRANES 2023; 13:370. [PMID: 37103797 PMCID: PMC10146956 DOI: 10.3390/membranes13040370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/13/2023] [Accepted: 03/20/2023] [Indexed: 06/19/2023]
Abstract
The interaction of antimicrobial and amyloid peptides with cell membranes is a critical step in their activities. Peptides of the uperin family obtained from the skin secretion of Australian amphibians demonstrate antimicrobial and amyloidogenic properties. All-atomic molecular dynamics and an umbrella sampling approach were used to study the interaction of uperins with model bacterial membrane. Two stable configurations of peptides were found. In the bound state, the peptides in helical form were located right under the head group region in parallel orientation with respect to the bilayer surface. Stable transmembrane configuration was observed for wild-type uperin and its alanine mutant in both alpha-helical and extended unstructured forms. The potential of mean force characterized the process of peptide binding from water to the lipid bilayer and its insertion into the membrane, and revealed that the transition of uperins from the bound state to the transmembrane position was accompanied by the rotation of peptides and passes through the energy barrier of 4-5 kcal/mol. Uperins have a weak effect on membrane properties.
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Prasad AK, Tiwari C, Ray S, Holden S, Armstrong DA, Rosengren KJ, Rodger A, Panwar AS, Martin LL. Secondary Structure Transitions for a Family of Amyloidogenic, Antimicrobial Uperin 3 Peptides in Contact with Sodium Dodecyl Sulfate. Chempluschem 2022; 87:e202100408. [DOI: 10.1002/cplu.202100408] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/10/2021] [Indexed: 11/10/2022]
Affiliation(s)
- Anup K. Prasad
- IITB-Monash Research Academy Indian Institute of Technology Bombay Powai Mumbai 400076 India
- Department of Metallurgical Engineering and Materials Science Indian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Chandni Tiwari
- IITB-Monash Research Academy Indian Institute of Technology Bombay Powai Mumbai 400076 India
- School of Chemistry Monash University Clayton VIC 3800 Australia
| | - Sourav Ray
- IITB-Monash Research Academy Indian Institute of Technology Bombay Powai Mumbai 400076 India
- Department of Metallurgical Engineering and Materials Science Indian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Stephanie Holden
- School of Chemistry Monash University Clayton VIC 3800 Australia
| | - David A. Armstrong
- School of Biomedical Sciences The University of Queensland Brisbane QLD, 4072 Australia
| | - K. Johan Rosengren
- School of Biomedical Sciences The University of Queensland Brisbane QLD, 4072 Australia
| | - Alison Rodger
- Department of Molecular Sciences Macquarie University Macquarie Park NSW, 2109 Australia
| | - Ajay S. Panwar
- Department of Metallurgical Engineering and Materials Science Indian Institute of Technology Bombay Powai Mumbai 400076 India
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Ray S, Holden S, Prasad AK, Martin LL, Panwar AS. Exploring the Role of Peptide Helical Stability in the Propensity of Uperin 3. x Peptides toward Beta-Aggregation. J Phys Chem B 2020; 124:11659-11670. [PMID: 33322900 DOI: 10.1021/acs.jpcb.0c10000] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Antimicrobial peptides of the uperin 3.x family, obtained from the skin secretions of Uperoleia mjobergii, have an inherent ability to form amyloid with possible functional roles and can serve as model peptides to understand mechanistic aspects of amyloidogenesis. The substitution of a positively charged amino acid with a nonpolar alanine residue increased aggregation, fibril content, and propensity for β-sheet formation for the uperin 3.5 R7A variant when compared with the uperin 3.5 wild-type peptides. We use molecular dynamics (MD) simulations and circular dichroism (CD) measurements on three uperin 3.x peptides and their corresponding seventh position alanine variants to understand the effect of substitution of a positively charged amino acid with a nonpolar alanine residue on the process of β-aggregation. Both CD experiments and simulations show that the uperin 3.x wild-type peptides demonstrated lower β-sheet content and propensity than with the corresponding alanine variants. Significantly, simulations of helix-to-coil transitions in individual peptides show an inverse relationship between the helical stability of peptides and their propensity to form structures rich in β-sheets as observed in CD experiments. A simulation scheme based on a conformational search of helix-to-coil transition trajectories to select peptide conformers was used to assemble propagating peptide oligomers. Whereas octamers consisting of lower helical stability peptide conformers evolve into compact aggregates with a large β-sheet component, octamers composed of high helical stability conformers disintegrate and show the least amounts of β-sheet components. The highlight of the current work is that MD simulations are able to predict the correct order of β-sheet propensity among the six peptides derived from the CD experiments and indicate the importance of helical intermediates in the amyloidogenesis pathway for uperin 3.x peptides.
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Affiliation(s)
- Sourav Ray
- IITB-Monash Research Academy, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.,School of Chemistry, Monash University, Clayton 3800, Victoria, Australia.,Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Stephanie Holden
- School of Chemistry, Monash University, Clayton 3800, Victoria, Australia
| | - Anup Kumar Prasad
- IITB-Monash Research Academy, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.,School of Chemistry, Monash University, Clayton 3800, Victoria, Australia.,Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Lisandra L Martin
- School of Chemistry, Monash University, Clayton 3800, Victoria, Australia
| | - Ajay Singh Panwar
- Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
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In Vitro Efficiency of Antimicrobial Peptides against Staphylococcal Pathogens Associated with Canine Pyoderma. Animals (Basel) 2020; 10:ani10030470. [PMID: 32168952 PMCID: PMC7143510 DOI: 10.3390/ani10030470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/06/2020] [Accepted: 03/08/2020] [Indexed: 12/17/2022] Open
Abstract
Simple Summary Coagulase-positive staphylococci (CoPS) are predominant pathogens in canine pyoderma, especially S. pseudintermedius and S. aureus. The antimicrobial resistance of CoPS has a key role in the management of canine skin infections. The vast majority of those diseases have a chronic character with a tendency to recur, which is reflected by recurrent systemic antibiotic therapy, associated with an alarming increase in the proportion of antibiotic-resistant staphylococci. Antimicrobial peptides (AMPs) seem to be a promising alternative to conventional antibiotics. The aim of this in vitro study was to evaluate the antimicrobial activity of selected AMPs against pathogenic staphylococcal strains, including multidrug- and methicillin-resistant strains isolated from canine pyoderma cases. The tested AMPs were shown to be equally efficient antimicrobial agents against resistant- and susceptible pathogenic staphylococcal strains associated with canine pyoderma. AMPs were more efficient against S. pseudintermedius than against S. aureus strains. Our findings seem to be particularly interesting from a clinical perspective, as a starting point from which to perform in vivo experiments to estimate the usefulness of these peptides as topical drug molecules for the treatment of canine pyoderma. Abstract The emergence of staphylococcal canine pathogens resistant to multiple antimicrobial agents is a growing and urgent problem in veterinary practice. Antimicrobial peptides (AMPs) seem to be a promising alternative to conventional antibiotics. The aim of this in vitro study was to evaluate the antimicrobial activity of selected AMPs against pathogenic staphylococcal strains, including multidrug- and methicillin-resistant strains isolated from canine pyoderma cases. Seven antimicrobial peptides (aurein 1.2, CAMEL, citropin 1.1, protegrin-1, pexiganan, temporin A and uperin 3.6) synthesized by the 9-fluorenylmethoxycarbonyl (Fmoc) solid-phase method were tested. The minimal inhibitory and minimal bactericidal concentrations (MIC and MBC) were determined by the broth microdilution method. The study showed that analyzed AMPs exerted an extensive effect against canine pathogens, with the most active peptide being uperin 3.6. The tested AMPs were equally efficient against both resistant- and susceptible staphylococcal strains and were more efficient against Staphylococcus pseudintermedius than against Staphylococcus aureus strains. Our findings are particularly interesting from a clinical perspective, as they point to AMPs as potential therapeutic topical agents in canine pyoderma cases associated with antimicrobial resistance of staphylococci.
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John T, Dealey TJA, Gray NP, Patil NA, Hossain MA, Abel B, Carver JA, Hong Y, Martin LL. The Kinetics of Amyloid Fibrillar Aggregation of Uperin 3.5 Is Directed by the Peptide’s Secondary Structure. Biochemistry 2019; 58:3656-3668. [DOI: 10.1021/acs.biochem.9b00536] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Torsten John
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
- Leibniz Institute of Surface Engineering (IOM), Permoserstraße 15, 04318 Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Leipzig University, Linnéstraße 3, 04103 Leipzig, Germany
| | - Tiara J. A. Dealey
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
| | - Nicholas P. Gray
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
| | - Nitin A. Patil
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Mohammed A. Hossain
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Bernd Abel
- Leibniz Institute of Surface Engineering (IOM), Permoserstraße 15, 04318 Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Leipzig University, Linnéstraße 3, 04103 Leipzig, Germany
| | - John A. Carver
- Research School of Chemistry, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Yuning Hong
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Lisandra L. Martin
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
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Martin LL, Kubeil C, Piantavigna S, Tikkoo T, Gray NP, John T, Calabrese AN, Liu Y, Hong Y, Hossain MA, Patil N, Abel B, Hoffmann R, Bowie JH, Carver JA. Amyloid aggregation and membrane activity of the antimicrobial peptide uperin 3.5. Pept Sci (Hoboken) 2018. [DOI: 10.1002/pep2.24052] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
| | - Clemens Kubeil
- School of Chemistry; Monash University; Clayton Victoria 3800 Australia
| | | | - Tarun Tikkoo
- School of Chemistry; Monash University; Clayton Victoria 3800 Australia
| | - Nicholas P. Gray
- School of Chemistry; Monash University; Clayton Victoria 3800 Australia
| | - Torsten John
- School of Chemistry; Monash University; Clayton Victoria 3800 Australia
- Leibniz Institute of Surface Engineering (IOM) and Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry; Leipzig University; Leipzig 04318 Germany
| | - Antonio N. Calabrese
- Department of Chemistry and School of Physical Sciences; The University of Adelaide; Adelaide South Australia 5005 Australia
| | - Yanqin Liu
- Department of Chemistry and School of Physical Sciences; The University of Adelaide; Adelaide South Australia 5005 Australia
| | - Yuning Hong
- Department of Chemistry and Physics; La Trobe Institute for Molecular Science, La Trobe University; Melbourne Victoria 3086 Australia
| | - Mohammed A. Hossain
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne; Parkville Victoria 3010 Australia
| | - Nitin Patil
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne; Parkville Victoria 3010 Australia
| | - Bernd Abel
- Leibniz Institute of Surface Engineering (IOM) and Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry; Leipzig University; Leipzig 04318 Germany
| | - Ralf Hoffmann
- Institute of Bioanalytical Chemistry, and Center for Biotechnology and Biomedicine (BBZ), Universität Leipzig; Leipzig 04103 Germany
| | - John H. Bowie
- Department of Chemistry and School of Physical Sciences; The University of Adelaide; Adelaide South Australia 5005 Australia
| | - John A. Carver
- Research School of Chemistry; The Australian National University; Acton Australian Capital Territory 2601 Australia
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Cardoso MH, Oshiro KG, Rezende SB, Cândido ES, Franco OL. The Structure/Function Relationship in Antimicrobial Peptides: What Can we Obtain From Structural Data? THERAPEUTIC PROTEINS AND PEPTIDES 2018; 112:359-384. [DOI: 10.1016/bs.apcsb.2018.01.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Patel S, Akhtar N. Antimicrobial peptides (AMPs): The quintessential 'offense and defense' molecules are more than antimicrobials. Biomed Pharmacother 2017; 95:1276-1283. [PMID: 28938518 DOI: 10.1016/j.biopha.2017.09.042] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/08/2017] [Accepted: 09/10/2017] [Indexed: 12/17/2022] Open
Abstract
Antimicrobial peptides (AMPs) are cationic amphiphilic molecules with α-helix or β-sheet linear motifs and linear or cyclic configurations. For their role in 'defense and offense', they are present in all living organisms. AMPs are named so, as they inhibit a wide array of microbes by membrane pore formation and subsequent perturbation of mitochondrial membrane ionic balance. However, their functional repertoire is expanding with validated roles in cytotoxicity, wound healing, angiogenesis, apoptosis, and chemotaxis [1]. A number of endogenous AMPs have been characterized in human body such as defensins, cathelicidins, histatins etc. They mediate critical functions, but when homeostasis is broken, they turn hostile and initiate inflammatory diseases. This review discusses the sources of therapeutic AMPs; auto-immunity risks of endogenous AMPs, and their dermatological applications; normally overlooked risks of the peptides; and scopes ahead. This holistic work is expected to be a valuable reference for further research in this field.
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Affiliation(s)
- Seema Patel
- Bioinformatics and Medical Informatics Research Center, San Diego State University, San Diego 92182, USA.
| | - Nadeem Akhtar
- Department of Animal Biosciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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12
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Garbacz K, Kamysz W, Piechowicz L. Activity of antimicrobial peptides, alone or combined with conventional antibiotics, against Staphylococcus aureus isolated from the airways of cystic fibrosis patients. Virulence 2016; 8:94-100. [PMID: 27450039 DOI: 10.1080/21505594.2016.1213475] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Katarzyna Garbacz
- a Department of Oral Microbiology , Medical University of Gdansk , Gdansk , Poland
| | - Wojciech Kamysz
- b Department of Inorganic Chemistry , Medical University of Gdansk , Gdansk , Poland
| | - Lidia Piechowicz
- c Department of Medical Microbiology , Medical University of Gdansk , Gdansk , Poland
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Calabrese AN, Liu Y, Wang T, Musgrave IF, Pukala TL, Tabor RF, Martin LL, Carver JA, Bowie JH. The Amyloid Fibril-Forming Properties of the Amphibian Antimicrobial Peptide Uperin 3.5. Chembiochem 2015; 17:239-46. [PMID: 26676975 DOI: 10.1002/cbic.201500518] [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: 10/07/2015] [Indexed: 12/13/2022]
Abstract
The amphibian skin is a vast resource for bioactive peptides, which form the basis of the animals' innate immune system. Key components of the secretions of the cutaneous glands are antimicrobial peptides (AMPs), which exert their cytotoxic effects often as a result of membrane disruption. It is becoming increasingly evident that there is a link between the mechanism of action of AMPs and amyloidogenic peptides and proteins. In this work, we demonstrate that the broad-spectrum amphibian AMP uperin 3.5, which has a random-coil structure in solution but adopts an α-helical structure in membrane-like environments, forms amyloid fibrils rapidly in solution at neutral pH. These fibrils are cytotoxic to model neuronal cells in a similar fashion to those formed by the proteins implicated in neurodegenerative diseases. The addition of small quantities of 2,2,2-trifluoroethanol accelerates fibril formation by uperin 3.5, and is correlated with a structural stabilisation induced by this co-solvent. Uperin 3.5 fibril formation and the associated cellular toxicity are inhibited by the polyphenol (-)-epigallocatechin-3-gallate (EGCG). Furthermore, EGCG rapidly dissociates fully formed uperin 3.5 fibrils. Ion mobility-mass spectrometry reveals that uperin 3.5 adopts various oligomeric states in solution. Combined, these observations imply that the mechanism of membrane permeability by uperin 3.5 is related to its fibril-forming properties.
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Affiliation(s)
- Antonio N Calabrese
- School of Physical Sciences or School of Medical Sciences, The University of Adelaide, Adelaide, 5005, South Australia, Australia
| | - Yanqin Liu
- School of Physical Sciences or School of Medical Sciences, The University of Adelaide, Adelaide, 5005, South Australia, Australia.,School of Technology, Hebei Agricultural University, Cangzhou, Hebei, 061100, China
| | - Tianfang Wang
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, 4556, Queensland, Australia
| | - Ian F Musgrave
- School of Physical Sciences or School of Medical Sciences, The University of Adelaide, Adelaide, 5005, South Australia, Australia
| | - Tara L Pukala
- School of Physical Sciences or School of Medical Sciences, The University of Adelaide, Adelaide, 5005, South Australia, Australia
| | - Rico F Tabor
- School of Chemistry, Monash University, Clayton, 3800, Victoria, Australia
| | - Lisandra L Martin
- School of Chemistry, Monash University, Clayton, 3800, Victoria, Australia.
| | - John A Carver
- Research School of Chemistry, The Australian National University, Acton, 2601, Australian Capital Territory, Australia.
| | - John H Bowie
- School of Physical Sciences or School of Medical Sciences, The University of Adelaide, Adelaide, 5005, South Australia, Australia
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Activity of Novel Synthetic Peptides against Candida albicans. Sci Rep 2015; 5:9657. [PMID: 25965506 PMCID: PMC4603303 DOI: 10.1038/srep09657] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/11/2015] [Indexed: 12/28/2022] Open
Abstract
Candida spp. are the most common causes of fungal infections worldwide. Among the Candida species, Candida albicans remains the predominant species that causes invasive candidiasis in most countries. In this study, we used two peptides, KABT-AMP and uperin 3.6 as templates to develop novel antifungal peptides. Their anticandidal activity was assessed using a combination of MIC, time-killing assay and biofilm reduction assay. Hybrid peptides, KU2 and KU3 containing a mixed backbone of KABT-AMP and Uperin 3.6 demonstrated the most potent anticandidal activity with MIC values ranging from 8–16 mg/L. The number of Trp residues and the amphipathic structure of peptides probably enhanced the anticandidal activity of peptides. Increasing the cationicity of the uperin 3.6 analogues resulted in reduced MIC from the range of 64–128 mg/L to 16–64 mg/L and this was also correlated with the antibiofilm activity and killing kinetics of the peptides. Peptides showed synergistic effects when used in combination with conventional antifungals. Peptides demonstrated low haemolytic activity but significant toxicity on two normal human epithelial cell lines. This study provides us with a better understanding on the structure-activity relationship and the balance between cationicity and hydrophobicity of the peptides although the therapeutic application of the peptides is limited.
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Xu X, Lai R. The chemistry and biological activities of peptides from amphibian skin secretions. Chem Rev 2015; 115:1760-846. [PMID: 25594509 DOI: 10.1021/cr4006704] [Citation(s) in RCA: 220] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Xueqing Xu
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology , Kunming 650223, Yunnan, China
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Bowie JH, Separovic F, Tyler MJ. Host-defense peptides of Australian anurans. Part 2. Structure, activity, mechanism of action, and evolutionary significance. Peptides 2012; 37:174-88. [PMID: 22771617 DOI: 10.1016/j.peptides.2012.06.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 06/26/2012] [Accepted: 06/26/2012] [Indexed: 01/01/2023]
Abstract
A previous review summarized research prior to 2004 carried out on the bioactive host-defense peptides contained in the skin secretions of Australian anurans (frogs and toads). This review covers the extension of that research from 2004 to 2012, and includes membrane-active peptides (including antibacterial, anticancer, antifungal and antiviral peptides) together with the mechanisms by which these peptides interact with model membranes, peptides that may be classified as "neuropeptides" (including smooth muscle active peptides, opioids and immunomodulators) and peptides which inhibit the formation of nitric oxide from neuronal nitric oxide synthase. The review discusses the outcome of cDNA sequencing of signal-spacer-active peptides from an evolutionary viewpoint, and also lists those peptides for which activities have not been found to this time.
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Affiliation(s)
- John H Bowie
- Department of Chemistry, School of Chemistry and Physics, The University of Adelaide, South Australia 5005, Australia.
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The contribution of skin antimicrobial peptides to the system of innate immunity in anurans. Cell Tissue Res 2010; 343:201-12. [PMID: 20640445 DOI: 10.1007/s00441-010-1014-4] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 06/08/2010] [Indexed: 10/19/2022]
Abstract
Cationic peptides with the propensity to adopt an amphipathic α-helical conformation in a membrane-mimetic environment are synthesized in the skins of many species of anurans (frogs and toads). These peptides frequently display cytolytic activities against a range of pathogenic bacteria and fungi consistent with the idea that they play a role in the host's system of innate immunity. However, the importance of the peptides in the survival strategy of the animal is not clearly understood. It is a common misconception that antimicrobial peptides are synthesized in the skins of all anurans. In fact, the species distribution is sporadic suggesting that their production may confer some evolutionary advantage to the organism but is not necessary for survival. Although growth inhibitory activity against the chytrid fungus Batrachochytrium dendrobatidis, responsible for anuran population declines worldwide, has been demonstrated in vitro, the ability of frog skin antimicrobial peptides to protect the animal in the wild appears to be limited and there is no clear correlation between their production by a species and its resistance to fatal chytridiomycosis. The low potency of many frog skin antimicrobial peptides is consistent with the hypothesis that cutaneous symbiotic bacteria may provide the major system of defense against pathogenic microorganisms in the environment with antimicrobial peptides assuming a supplementary role in some species.
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Johnson SR, Copello JA, Evans MS, Suarez AV. A biochemical characterization of the major peptides from the Venom of the giant Neotropical hunting ant Dinoponera australis. Toxicon 2009; 55:702-10. [PMID: 19879289 DOI: 10.1016/j.toxicon.2009.10.021] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 10/09/2009] [Accepted: 10/15/2009] [Indexed: 10/20/2022]
Abstract
Venom from the "false tocandira"Dinoponera australis, a giant Neotropical hunting ant, paralyzes small invertebrate prey and induces a myriad of systemic effects in large vertebrates. HPLC/DAD/MS analyses revealed that the venom has over 75 unique proteinaceous components with a large diversity of properties ranging in size, hydrophobicity, and overall abundance. The six most abundant peptides, demonstrative of this diversity and hereafter referred to as Dinoponeratoxins, were de novo sequenced by exact mass precursor ion selection and Edman degradation. The smallest peptide characterized, Da-1039, is hydrophilic and has similarities to vasoactive peptides like kinin and bombesin. The two largest and most abundant peptides, Da-3105 and Da-3177, have a 92.9% identity in a 28 residue overlap and share approximately 50 of their sequence with ponericin G2 (an antimicrobial from another ponerine ant Pachycondyla goeldii). One peptide, Da-1585, is a hydrophilic cleavage product of an amphipathic peptide, Da-2501. The most hydrophobic peptide, Da-1837, is amidated (a PTM observed in one half of the major peptides) and shares homology with poneratoxin, a sodium channel modifier found in the bullet ant Paraponera clavata. This study is the first examination of potential pharmacophores from venom of the genus Dinoponera (Order: Hymenoptera).
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Affiliation(s)
- Stephen R Johnson
- Carbon Dynamics Institute, LLC, 2835 Via Verde Drive, Springfield, IL 62703-4325, USA.
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19
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Conlon JM, Demandt A, Nielsen PF, Leprince J, Vaudry H, Woodhams DC. The alyteserins: two families of antimicrobial peptides from the skin secretions of the midwife toad Alytes obstetricans (Alytidae). Peptides 2009; 30:1069-73. [PMID: 19463738 DOI: 10.1016/j.peptides.2009.03.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 03/07/2009] [Accepted: 03/09/2009] [Indexed: 10/21/2022]
Abstract
Two families of structurally related C-terminally alpha-amidated antimicrobial peptides have been identified in norepinephrine-stimulated skin secretions of the midwife toad Alytes obstetricans (Alytidae). The alyteserin-1 peptides (Gly-Leu-Lys-(Asp/Glu)-Ile-Phe-Lys-Ala-Gly-Leu-Gly-Ser-Leu-Val-Lys-(Gly/Asn)-Ile-Ala-Ala-His-Val-Ala-(Asn/Ser).NH(2)) show limited structural similarity to the ascaphins from the skins of frogs of the family Leiopelmatidae. Alyteserin-2a (Ile-Leu-Gly-Lys-Leu-Leu-Ser-Thr-Ala-Ala-Gly-Leu-Leu-Ser-Asn-Leu.NH(2)) and alyteserin-2b and -2c (Ile-Leu-Gly-Ala-Ile-Leu-Pro-Leu-Val-Ser-Gly-Leu-Leu-Ser-(Asn/Ser)-Lys-Leu x NH(2)) show limited sequence identity with bombinin H6, present in the skins of frogs of the family Bombinatoridae. The alyteserin-1 peptides show selective growth inhibitory activity against the Gram-negative bacteria Escherichia coli (MIC=25 microM) whereas alyteserin-2a is more potent against the Gram-positive bacteria Staphylococcus aureus (MIC=50 microM). The hemolytic activity against human erythrocytes of all peptides tested is relatively weak (LC(50)>100 microM). The data demonstrate that the frogs belonging to the family Alytidae are among those producing dermal antimicrobial peptides that may represent a component of the animal's system of innate immunity.
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Affiliation(s)
- J Michael Conlon
- Department of Biochemistry, Faculty of Medicine and Health Sciences, United Arab Emirates University, 17666 Al-Ain, United Arab Emirates.
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20
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Haney EF, Hunter HN, Matsuzaki K, Vogel HJ. Solution NMR studies of amphibian antimicrobial peptides: linking structure to function? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1639-55. [PMID: 19272309 DOI: 10.1016/j.bbamem.2009.01.002] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 12/19/2008] [Accepted: 01/09/2009] [Indexed: 10/21/2022]
Abstract
The high-resolution three-dimensional structure of an antimicrobial peptide has implications for the mechanism of its antimicrobial activity, as the conformation of the peptide provides insights into the intermolecular interactions that govern the binding to its biological target. For many cationic antimicrobial peptides the negatively charged membranes surrounding the bacterial cell appear to be a main target. In contrast to what has been found for other classes of antimicrobial peptides, solution NMR studies have revealed that in spite of the wide diversity in the amino acid sequences of amphibian antimicrobial peptides (AAMPs), they all adopt amphipathic alpha-helical structures in the presence of membrane-mimetic micelles, bicelles or organic solvent mixtures. In some cases the amphipathic AAMP structures are directly membrane-perturbing (e.g. magainin, aurein and the rana-box peptides), in other instances the peptide spontaneously passes through the membrane and acts on intracellular targets (e.g. buforin). Armed with a high-resolution structure, it is possible to relate the peptide structure to other relevant biophysical and biological data to elucidate a mechanism of action. While many linear AAMPs have significant antimicrobial activity of their own, mixtures of peptides sometimes have vastly improved antibiotic effects. Thus, synergy among antimicrobial peptides is an avenue of research that has recently attracted considerable attention. While synergistic relationships between AAMPs are well described, it is becoming increasingly evident that analyzing the intermolecular interactions between these peptides will be essential for understanding the increased antimicrobial effect. NMR structure determination of hybrid peptides composed of known antimicrobial peptides can shed light on these intricate synergistic relationships. In this work, we present the first NMR solution structure of a hybrid peptide composed of magainin 2 and PGLa bound to SDS and DPC micelles. The hybrid peptide adopts a largely helical conformation and some information regarding the inter-helix organization of this molecule is reported. The solution structure of the micelle associated MG2-PGLa hybrid peptide highlights the importance of examining structural contributions to the synergistic relationships but it also demonstrates the limitations in the resolution of the currently used solution NMR techniques for probing such interactions. Future studies of antimicrobial peptide synergy will likely require stable isotope-labeling strategies, similar to those used in NMR studies of proteins.
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Affiliation(s)
- Evan F Haney
- Structural Biology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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21
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Fernandez DI, Gehman JD, Separovic F. Membrane interactions of antimicrobial peptides from Australian frogs. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1788:1630-8. [PMID: 19013126 DOI: 10.1016/j.bbamem.2008.10.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 10/08/2008] [Accepted: 10/12/2008] [Indexed: 10/21/2022]
Abstract
The membrane interactions of four antimicrobial peptides, aurein 1.2, citropin 1.1, maculatin 1.1 and caerin 1.1, isolated from Australian tree frogs, are reviewed. All four peptides are amphipathic alpha-helices with a net positive charge and range in length from 13 to 25 residues. Despite several similar sequence characteristics, these peptides compromise the integrity of model membrane bilayers via different mechanisms; the shorter peptides exhibit a surface interaction mechanism while the longer peptides may form pores in membranes.
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Affiliation(s)
- David I Fernandez
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne VIC 3010, Australia
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22
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Giacometti A, Cirioni O, Ghiselli R, Mocchegiani F, Silvestri C, Orlando F, Kamysz W, Licci A, Kamysz E, Lukasiak J, Saba V, Scalise G. Amphibian peptides prevent endotoxemia and bacterial translocation in bile duct–ligated rats*. Crit Care Med 2006; 34:2415-20. [PMID: 16791114 DOI: 10.1097/01.ccm.0000231879.11963.eb] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate the efficacy of amphibian antimicrobial peptides in preventing bacterial translocation and neutralizing endotoxins in bile duct-ligated rats. DESIGN Prospective, randomized, controlled animal study. SETTING Research laboratory in a university hospital. SUBJECTS Adult male Wistar rats. INTERVENTIONS Adult male Wistar rats underwent sham operation or bile duct ligation (BDL). Eight groups were studied: sham operation with saline treatment, sham operation with 120 mg/kg tazobactam-piperacillin, sham operation with 2 mg/kg uperin 3.6, sham operation with 2 mg/kg magainin2, BDL with saline treatment, BDL with 120 mg/kg tazobactam-piperacillin, BDL with 2 mg/kg uperin 3.6, and BDL with 2 mg/kg magainin2. MEASUREMENTS AND MAIN RESULTS Main outcome measures were: endotoxin and tumor necrosis factor-alpha concentrations in plasma and evidence of bacterial translocation in blood, peritoneum, liver, and mesenteric lymph nodes. Endotoxin and tumor necrosis factor-alpha plasma levels were significantly higher in BDL rats compared with sham-operated animals. All amphibian peptides achieved a significant reduction of plasma endotoxin and tumor necrosis factor-alpha concentration when compared with saline- and tazobactam-piperacillin-treated groups. On the other hand, both tazobactam-piperacillin and peptides significantly reduced bacterial growth compared with the control. Tazobactam-piperacillin and magainin2 exerted the maximal inhibition of bacterial growth. CONCLUSION In conclusion, because of their multifunctional properties, amphibian peptides could be interesting compounds to inhibit bacterial translocation and endotoxin release in obstructive jaundice.
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Affiliation(s)
- Andrea Giacometti
- Institute of Infectious Diseases and Public Health, Università Politecnica delle Marche, Ancona, Italy
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23
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Pukala TL, Bowie JH, Maselli VM, Musgrave IF, Tyler MJ. Host-defence peptides from the glandular secretions of amphibians: structure and activity. Nat Prod Rep 2006; 23:368-93. [PMID: 16741585 DOI: 10.1039/b512118n] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Tara L Pukala
- Department of Chemistry, The University of Adelaide, South Australia
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24
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Giacometti A, Cirioni O, Kamysz W, Silvestri C, Licci A, D'Amato G, Nadolski P, Riva A, Lukasiak J, Scalise G. In vitro activity and killing effect of uperin 3.6 against gram-positive cocci isolated from immunocompromised patients. Antimicrob Agents Chemother 2005; 49:3933-6. [PMID: 16127075 PMCID: PMC1195410 DOI: 10.1128/aac.49.9.3933-3936.2005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The in vitro activity of uperin 3.6, alone or combined with six antibiotics, against gram-positive cocci, including Rhodococcus equi, methicillin-resistant staphylococci, and vancomycin-resistant enterococci, was investigated. All isolates were inhibited at concentrations of 1 to 16 mg/liter. Synergy was demonstrated when uperin 3.6 was combined with clarithromycin and doxycycline.
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Affiliation(s)
- Andrea Giacometti
- Institute of Infectious Diseases and Public Health, c/o Ospedale Regionale, via Conca, 71, Ancona, I-60020, Italy.
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25
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Woodhams DC, Rollins-Smith LA, Carey C, Reinert L, Tyler MJ, Alford RA. Population trends associated with skin peptide defenses against chytridiomycosis in Australian frogs. Oecologia 2005; 146:531-40. [PMID: 16205955 DOI: 10.1007/s00442-005-0228-8] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Accepted: 07/25/2005] [Indexed: 11/30/2022]
Abstract
Many species of amphibians in the wet tropics of Australia have experienced population declines linked with the emergence of a skin-invasive chytrid fungus, Batrachochytrium dendrobatidis. An innate defense, antimicrobial peptides produced by granular glands in the skin, may protect some species from disease. Here we present evidence that supports this hypothesis. We tested ten synthesized peptides produced by Australian species, and natural peptide mixtures from five Queensland rainforest species. Natural mixtures and most peptides tested in isolation inhibited growth of B. dendrobatidis in vitro. The three most active peptides (caerin 1.9, maculatin 1.1, and caerin 1.1) were found in the secretions of non-declining species (Litoria chloris, L. caerulea, and L. genimaculata). Although the possession of a potent isolated antimicrobial peptide does not guarantee protection from infection, non-declining species (L. lesueuri and L. genimaculata) inhabiting the rainforest of Queensland possess mixtures of peptides that may be more protective than those of the species occurring in the same habitat that have recently experienced population declines associated with chytridiomycosis (L. nannotis, L. rheocola, and Nyctimystes dayi). This study demonstrates that in vitro effectiveness of skin peptides correlates with the degree of decline in the face of an emerging pathogen. Further research is needed to assess whether this non-specific immune defense may be useful in predicting disease susceptibility in other species.
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Affiliation(s)
- Douglas C Woodhams
- School of Tropical Biology, James Cook University, 4811, Townsville, QLD, Australia.
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26
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Apponyi MA, Pukala TL, Brinkworth CS, Maselli VM, Bowie JH, Tyler MJ, Booker GW, Wallace JC, Carver JA, Separovic F, Doyle J, Llewellyn LE. Host-defence peptides of Australian anurans: structure, mechanism of action and evolutionary significance. Peptides 2004; 25:1035-54. [PMID: 15203252 DOI: 10.1016/j.peptides.2004.03.006] [Citation(s) in RCA: 172] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2003] [Revised: 03/10/2004] [Accepted: 03/11/2004] [Indexed: 11/26/2022]
Abstract
Host-defence peptides secreted from the skin glands of Australian frogs and toads, are, with a few notable exceptions, different from those produced by anurans elsewhere. This review summarizes the current knowledge of the following classes of peptide isolated and characterized from Australian anurans: neuropeptides (including smooth muscle active peptides, and peptides that inhibit the production of nitric oxide from neuronal nitric oxide synthase), antimicrobial and anticancer active peptides, antifungal peptides and antimalarial peptides. Other topics covered include sex pheromones of anurans, and the application of peptide profiling to (i). recognize particular populations of anurans of the same species and to differentiate between species, and (ii). investigate evolutionary aspects of peptide formation.
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Affiliation(s)
- Margit A Apponyi
- Department of Chemistry, The University of Adelaide, Adelaide, South Australia 5005, Australia
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Rozek T, Wegener KL, Bowie JH, Olver IN, Carver JA, Wallace JC, Tyler MJ. The antibiotic and anticancer active aurein peptides from the Australian Bell Frogs Litoria aurea and Litoria raniformis the solution structure of aurein 1.2. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:5330-41. [PMID: 10951191 DOI: 10.1046/j.1432-1327.2000.01536.x] [Citation(s) in RCA: 203] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Seventeen aurein peptides are present in the secretion from the granular dorsal glands of the Green and Golden Bell Frog Litoria aurea, and 16 from the corresponding secretion of the related Southern Bell Frog L. raniformis. Ten of these peptides are common to both species. Thirteen of the aurein peptides show wide-spectrum antibiotic and anticancer activity. These peptides are named in three groups (aureins 1-3) according to their sequences. Amongst the more active peptides are aurein 1.2 (GLFDIIKKIAESF-NH2), aurein 2.2 (GLFDIVKKVVGALGSL-NH2) and aurein 3.1 (GLFDIVKKIAGHIAGSI-NH2). Both L. aurea and L. raniformis have endoproteases that deactivate the major membrane-active aurein peptides by removing residues from both the N- and C-termini of the peptides. The most abundant degradation products have two residues missing from the N-terminal end of the peptide. The solution structure of the basic peptide, aurein 1.2, has been determined by NMR spectroscopy to be an amphipathic alpha-helix with well-defined hydrophilic and hydrophobic regions. Certain of the aurein peptides (e.g. aureins 1.2 and 3.1) show anticancer activity in the NCI test regime, with LC50 values in the 10-5-10-4 M range. The aurein 1 peptides have only 13 amino-acid residues: these are the smallest antibiotic and anticancer active peptides yet reported from an anuran. The longer aurein 4 and 5 peptides, e.g. aurein 4.1 (GLIQTIKEKLKELAGGLVTGIQS-OH) and aurein 5. 1 (GLLDIVTGLLGNLIVDVLKPKTPAS-OH) show neither antibacterial nor anticancer activity.
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Affiliation(s)
- T Rozek
- Department of Chemistry, The University of Adelaide, South Australia, Australia
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28
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Chia BC, Carver JA, Mulhern TD, Bowie JH. Maculatin 1.1, an anti-microbial peptide from the Australian tree frog, Litoria genimaculata solution structure and biological activity. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:1894-908. [PMID: 10727928 DOI: 10.1046/j.1432-1327.2000.01089.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The dorsal glands of Australian tree frogs from the Litoria species contain a diversity of antibiotic peptides that forms part of the defence system of the animal. Here, the antibiotic activity and structure of maculatin 1.1, a 21 amino acid peptide from Litoria genimaculata, are compared. The activity data on maculatin 1.1 and a series of its analogues imply that the mechanism of action of maculatin 1.1 involves binding to, and subsequent lysis of, the bacterial cell membrane. The structure of maculatin 1.1 was determined using NMR spectroscopy in a trifluoroethanol/water mixture and when incorporated into dodecylphosphocholine micelles. Under both conditions, the peptide adopts a very similar conformation, i.e. a helical structure with a central kink in the vicinity of Pro15. The kink allows the peptide to adopt a well-defined amphipathic conformation along its entire length. The similar structures determined under both solvent conditions imply that structures of membrane-interacting peptides in trifluoroethanol/water mixtures are representative of those adopted in a membrane environment, e.g. when incorporated into micelles. The synthetic Ala15 analogue of maculatin 1.1 has markedly reduced activity and its NMR-derived structure is a well-defined helix, which lacks the central kink and flexibility of the parent molecule. It is concluded that the kink is important for full biological activity of the peptide, probably because it allows maximum amphipathicity of the peptide to facilitate interaction with the membrane. The structure of maculatin 1.1 is compared with a related peptide, caerin 1.1 [Wong, H., Bowie, J.H. and Carver, J.A. (1997) Eur. J. Biochem. 247, 545-557], which has an additional central proline residue and enhanced central flexibility compared with maculatin 1.1. The role of central flexibility within antibiotic peptides in their interaction with bacterial membranes is discussed.
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Affiliation(s)
- B C Chia
- Department of Chemistry, The University of Adelaide, Australia
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29
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Wegener KL, Wabnitz PA, Carver JA, Bowie JH, Chia BC, Wallace JC, Tyler MJ. Host defence peptides from the skin glands of the Australian blue mountains tree-frog Litoria citropa. Solution structure of the antibacterial peptide citropin 1.1. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 265:627-37. [PMID: 10504394 DOI: 10.1046/j.1432-1327.1999.00750.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Nineteen citropin peptides are present in the secretion from the granular dorsal glands of the Blue Mountains tree-frog Litoria citropa; 15 of these peptides are also present in the secretion from the submental gland. Two major peptides, citropin 1.1 (GLFDVIKKVASVIGGL-NH2), citropin 1.2 (GLFDIIKKVASVVGGL-NH2) and a minor peptide, citropin 1.3 (GLFDIIKKVASVIGGL-NH2) are wide-spectrum antibacterial peptides. The amphibian has an endoprotease which deactivates these membrane-active peptides by removing residues from the N-terminal end: loss of three residues gives the most abundant degradation products. The solution structure of the basic peptide citropin 1.1 has been determined by NMR spectroscopy [in a solvent mixture of trifluoroethanol/water (1 : 1)] to be an amphipathic alpha-helix with well-defined hydrophobic and hydrophilic regions. The additional four peptides produced by the dorsal glands are structurally related to the antibacterial citropin 1 peptides but contain three more residues at their C-terminus [e.g. citropin 1.1.3 (GLFDVIKKVASVIGLASP-OH)]. These peptides show minimal antibacterial activity; their role in the amphibian skin is not known.
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Affiliation(s)
- K L Wegener
- Department of Chemistry, The University of Adelaide, South Australia, Australia
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