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Liang Q, Liu Z, Liang Z, Zhu C, Li D, Kong Q, Mou H. Development strategies and application of antimicrobial peptides as future alternatives to in-feed antibiotics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:172150. [PMID: 38580107 DOI: 10.1016/j.scitotenv.2024.172150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 03/14/2024] [Accepted: 03/30/2024] [Indexed: 04/07/2024]
Abstract
The use of in-feed antibiotics has been widely restricted due to the significant environmental pollution and food safety concerns they have caused. Antimicrobial peptides (AMPs) have attracted widespread attention as potential future alternatives to in-feed antibiotics owing to their demonstrated antimicrobial activity and environment friendly characteristics. However, the challenges of weak bioactivity, immature stability, and low production yields of natural AMPs impede practical application in the feed industry. To address these problems, efforts have been made to develop strategies for approaching the AMPs with enhanced properties. Herein, we summarize approaches to improving the properties of AMPs as potential alternatives to in-feed antibiotics, mainly including optimization of structural parameters, sequence modification, selection of microbial hosts, fusion expression, and industrially fermentation control. Additionally, the potential for application of AMPs in animal husbandry is discussed. This comprehensive review lays a strong theoretical foundation for the development of in-feed AMPs to achieve the public health globally.
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Affiliation(s)
- Qingping Liang
- College of Food Science and Engineering, Ocean University of China, Qingdao 266404, China
| | - Zhemin Liu
- Fundamental Science R&D Center of Vazyme Biotech Co. Ltd., Nanjing 210000, China
| | - Ziyu Liang
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Changliang Zhu
- College of Food Science and Engineering, Ocean University of China, Qingdao 266404, China
| | - Dongyu Li
- College of Food Science and Engineering, Ocean University of China, Qingdao 266404, China
| | - Qing Kong
- College of Food Science and Engineering, Ocean University of China, Qingdao 266404, China
| | - Haijin Mou
- College of Food Science and Engineering, Ocean University of China, Qingdao 266404, China.
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Peptides Isolated from Amphibian Skin Secretions with Emphasis on Antimicrobial Peptides. Toxins (Basel) 2022; 14:toxins14100722. [PMID: 36287990 PMCID: PMC9607450 DOI: 10.3390/toxins14100722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/07/2022] [Accepted: 10/19/2022] [Indexed: 11/19/2022] Open
Abstract
The skin of amphibians is a tissue with biological functions, such as defense, respiration, and excretion. In recent years, researchers have discovered a large number of peptides in the skin secretions of amphibians, including antimicrobial peptides, antioxidant peptides, bradykinins, insulin-releasing peptides, and other peptides. This review focuses on the origin, primary structure, secondary structure, length, and functions of peptides secreted from amphibians' skin. We hope that this review will provide further information and promote the further study of amphibian skin secretions, in order to provide reference for expanding the research and application of amphibian bioactive peptides.
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Zhao Y, Wang XY, Sun Y, Li Z, Liu T, Liu QM, Chen J. Truncated analog Brevinin2-CE-N26V5K: Revelation the Augmentation of Antimicrobial Activity. World J Microbiol Biotechnol 2022; 38:162. [PMID: 35834028 DOI: 10.1007/s11274-022-03333-1] [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: 02/09/2022] [Accepted: 06/10/2022] [Indexed: 11/30/2022]
Abstract
Brevinin2-CE (B2CE), a natural peptide containing 37 amino acids, was first isolated from the skin secretions of the Chinese forest frog Rana chensinensis. B2CE shows good antibacterial activity. In this study, a series of B2CE analogs with differences in cationicity, α-helicity, hydrophobicity and amphipathic properties were designed through chain-length deletion and amino acid substitution. The most potent, nontoxic analog, B2CE-N26V5K, was identified by examination of its antibacterial activity, hemolytic activity, and stability under physiological conditions. The increased cationicity, hydrophobicity and more obvious hydrophilic and hydrophobic surface of B2CE-N26-N16WA18KG23K did not improve the antibacterial activity but increased the hemolytic activity of this modified peptide. The helicity might promote antibacterial activity for brevinin-2 peptides, as the 15-aa analogs with lower helicity show decreased potency against different test bacteria (approximately 2- to 72-fold) compared to B2CE-N26V5K. Additionally, the results indicated that the "Rana box" does not affect the antimicrobial activity of brevinin-2 peptides, as B2CE, B2CE-nonDS and B2CE-C31-37 S have similar strong inhibitory effects on both gram-positive and gram-negative bacteria. However, the "Rana box" does affect the hemolytic activity, as the HC50 values of the 3 peptides range from 25 ~ 130 µM. Furthermore, B2CE-N26V5K caused obvious morphological alterations of the bacterial surfaces, as shown by atomic force microscopy. Additionally, B2CE-N26V5K exhibited strong membrane-disrupting activity when examined using the LIVE/DEAD Bac Light Bacterial Viability Kit. Thus, the antibacterial effect of B2CE-N26V5K on gram-negative and gram-positive bacteria may be caused by cell membrane attack. In conclusion, the excellent candidate B2CE-N26V5K was obtained and has application prospects as a novel anti-infective agent.
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Affiliation(s)
- Yi Zhao
- College of Life Sciences, Shaanxi Normal University, 710119, Xi'an, P. R. China
| | - Xiao-Yan Wang
- College of Life Sciences, Shaanxi Normal University, 710119, Xi'an, P. R. China
| | - Yan Sun
- College of Life Sciences, Shaanxi Normal University, 710119, Xi'an, P. R. China.
| | - Zhi Li
- College of Life Sciences, Shaanxi Normal University, 710119, Xi'an, P. R. China.
| | - Tao Liu
- College of Life Sciences, Shaanxi Normal University, 710119, Xi'an, P. R. China
| | - Qing-Mei Liu
- College of Life Sciences, Shaanxi Normal University, 710119, Xi'an, P. R. China
| | - Jingyi Chen
- College of Life Sciences, Shaanxi Normal University, 710119, Xi'an, P. R. China
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Patocka J, Nepovimova E, Klimova B, Wu Q, Kuca K. Antimicrobial Peptides: Amphibian Host Defense Peptides. Curr Med Chem 2019; 26:5924-5946. [PMID: 30009702 DOI: 10.2174/0929867325666180713125314] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/05/2018] [Accepted: 07/06/2018] [Indexed: 02/07/2023]
Abstract
Antimicrobial Peptides (AMPs) are one of the most common components of the innate immune system that protect multicellular organisms against microbial invasion. The vast majority of AMPs are isolated from the frog skin. Anuran (frogs and toads) skin contains abundant AMPs that can be developed therapeutically. Such peptides are a unique but diverse group of molecules. In general, more than 50% of the amino acid residues form the hydrophobic part of the molecule. Normally, there are no conserved structural motifs responsible for activity, although the vast majority of the AMPs are cationic due to the presence of multiple lysine residues; this cationicity has a close relationship with antibacterial activity. Notably, recent evidence suggests that synthesis of AMPs in frog skin may confer an advantage on a particular species, although they are not essential for survival. Frog skin AMPs exert potent activity against antibiotic-resistant bacteria, protozoa, yeasts, and fungi by permeating and destroying the plasma membrane and inactivating intracellular targets. Importantly, since they do not bind to a specific receptor, AMPs are less likely to induce resistance mechanisms. Currently, the best known amphibian AMPs are esculentins, brevinins, ranacyclins, ranatuerins, nigrocin-2, magainins, dermaseptins, bombinins, temporins, and japonicins-1 and -2, and palustrin-2. This review focuses on these frog skin AMPs and the mechanisms underlying their antimicrobial activity. We hope that this review will provide further information that will facilitate further study of AMPs and cast new light on novel and safer microbicides.
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Affiliation(s)
- Jiri Patocka
- Department of Radiology and Toxicology, Faculty of Health and Social Studies, University of South Bohemia Ceske Budejovice, Ceske Budejovice, Czech Republic
| | - Eugenie Nepovimova
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
| | - Blanka Klimova
- Faculty of Informatics and Management, University of Hradec Kralove, Hradec Kralove, Czech Republic
| | - Qinghua Wu
- College of Life Science, Institute of Biomedicine, Yangtze University, Jingzhou 434025, China
| | - Kamil Kuca
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
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5
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Ageitos J, Sánchez-Pérez A, Calo-Mata P, Villa T. Antimicrobial peptides (AMPs): Ancient compounds that represent novel weapons in the fight against bacteria. Biochem Pharmacol 2017; 133:117-138. [DOI: 10.1016/j.bcp.2016.09.018] [Citation(s) in RCA: 328] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/19/2016] [Indexed: 01/01/2023]
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Kozić M, Vukičević D, Simunić J, Rončević T, Antcheva N, Tossi A, Juretić D. Predicting the Minimal Inhibitory Concentration for Antimicrobial Peptides with Rana-Box Domain. J Chem Inf Model 2015; 55:2275-87. [PMID: 26332863 DOI: 10.1021/acs.jcim.5b00161] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The global spreading of multidrug resistance has motivated the search for new antibiotic classes including different types of antimicrobial peptides (AMPs). Computational methods for predicting activity in terms of the minimal inhibitory concentration (MIC) of AMPs can facilitate "in silico" design and reduce the cost of synthesis and testing. We have used an original method for separating training and test data sets, both of which contain the sequences and measured MIC values of non-homologous anuran peptides having the Rana-box disulfide motif at their C-terminus. Using a more flexible profiling methodology (sideways asymmetry moment, SAM) than the standard hydrophobic moment, we have developed a two-descriptor model to predict the bacteriostatic activity of Rana-box peptides against Gram-negative bacteria--the first multilinear quantitative structure-activity relationship model capable of predicting MIC values for AMPs of widely different lengths and low identity using such a small number of descriptors. Maximal values for SAMs, as defined and calculated in our method, furthermore offer new structural insight into how different segments of a peptide contribute to its bacteriostatic activity, and this work lays the foundations for the design of active artificial AMPs with this type of disulfide bridge.
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Affiliation(s)
- Mara Kozić
- Institute of Integrative Biology, University of Liverpool , Liverpool L69 7ZB, U.K
| | - Damir Vukičević
- Faculty of Science, University of Split , 21000 Split, Croatia
| | - Juraj Simunić
- Mediterranean Institute for Life Sciences , 21000 Split, Croatia
| | | | - Nikolinka Antcheva
- Department of Life Sciences, University of Trieste , 34127 Trieste, Italy
| | - Alessandro Tossi
- Department of Life Sciences, University of Trieste , 34127 Trieste, Italy
| | - Davor Juretić
- Faculty of Science, University of Split , 21000 Split, Croatia
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7
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Liu L, Fang Y, Wu J. Flexibility is a mechanical determinant of antimicrobial activity for amphipathic cationic α-helical antimicrobial peptides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2479-86. [DOI: 10.1016/j.bbamem.2013.06.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 06/02/2013] [Accepted: 06/13/2013] [Indexed: 01/27/2023]
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Abstract
AbstractIncreased prevalence of multi-drug resistance in pathogens has encouraged researchers to focus on finding novel forms of anti-infective agents. Antimicrobial peptides (AMPs) found in animal secretions are components of host innate immune response and have survived eons of pathogen evolution. Thus, they are likely to be active against pathogens and even those that are resistant to conventional drugs. Many peptides have been isolated and shown to be effective against multi-drug resistant pathogens. More than 500 AMPs have been identified from amphibians. The abundance of AMPs in frog skin is remarkable and constitutes a rich source for design of novel pharmaceutical molecules. Expression and post-translational modifications, discovery, activities and probable therapeutic application prospects of amphibian AMPs will be discussed in this article.
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Affiliation(s)
- Yao Xiao
- 1Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan, China
| | - Cunbao Liu
- 1Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan, China
| | - Ren Lai
- 1Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan, China
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9
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Duchardt F, Ruttekolk IR, Verdurmen WPR, Lortat-Jacob H, Bürck J, Hufnagel H, Fischer R, van den Heuvel M, Löwik DWPM, Vuister GW, Ulrich A, de Waard M, Brock R. A cell-penetrating peptide derived from human lactoferrin with conformation-dependent uptake efficiency. J Biol Chem 2009; 284:36099-36108. [PMID: 19858187 DOI: 10.1074/jbc.m109.036426] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The molecular events that contribute to the cellular uptake of cell-penetrating peptides (CPP) are still a matter of intense research. Here, we report on the identification and characterization of a 22-amino acid CPP derived from the human milk protein, lactoferrin. The peptide exhibits a conformation-dependent uptake efficiency that is correlated with efficient binding to heparan sulfate and lipid-induced conformational changes. The peptide contains a disulfide bridge formed by terminal cysteine residues. At concentrations exceeding 10 mum, this peptide undergoes the same rapid entry into the cytoplasm that was described previously for the arginine-rich CPPs nona-arginine and Tat. Cytoplasmic entry strictly depends on the presence of the disulfide bridge. To better understand this conformation dependence, NMR spectroscopy was performed for the free peptide, and CD measurements were performed for free and lipid-bound peptide. In solution, the peptides showed only slight differences in secondary structure, with a predominantly disordered structure both in the presence and absence of the disulfide bridge. In contrast, in complex with large unilamellar vesicles, the conformation of the oxidized and reduced forms of the peptide clearly differed. Moreover, surface plasmon resonance experiments showed that the oxidized form binds to heparan sulfate with a considerably higher affinity than the reduced form. Consistently, membrane binding and cellular uptake of the peptide were reduced when heparan sulfate chains were removed.
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Affiliation(s)
- Falk Duchardt
- Interfaculty Institute for Cell Biology, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Ivo R Ruttekolk
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, 6525 GA Nijmegen, The Netherlands
| | - Wouter P R Verdurmen
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, 6525 GA Nijmegen, The Netherlands
| | - Hugues Lortat-Jacob
- Institut de Biologie Structurale, UMR 5075 CEA-CNRS, Université Joseph Fourier, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France
| | - Jochen Bürck
- Karlsruhe Institute of Technology, Forschungszentrum Karlsruhe, IBG-2, 76131 Karlsruhe, Germany
| | - Hansjörg Hufnagel
- Interfaculty Institute for Cell Biology, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Rainer Fischer
- Interfaculty Institute for Cell Biology, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Maaike van den Heuvel
- Department of Bio-Organic Chemistry, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Dennis W P M Löwik
- Department of Bio-Organic Chemistry, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Geerten W Vuister
- Department of Protein Biophysics, Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Anne Ulrich
- Karlsruhe Institute of Technology, Forschungszentrum Karlsruhe, IBG-2, 76131 Karlsruhe, Germany
| | - Michel de Waard
- INSERM U836, Université Joseph Fourier, Grenoble Neuroscience Institute, Group 3, 38027 Grenoble Cedex 1, France
| | - Roland Brock
- Interfaculty Institute for Cell Biology, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany; Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, 6525 GA Nijmegen, The Netherlands.
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Subasinghage AP, Conlon JM, Hewage CM. Conformational analysis of the broad-spectrum antibacterial peptide, ranatuerin-2CSa: identification of a full length helix-turn-helix motif. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:924-9. [PMID: 18387372 DOI: 10.1016/j.bbapap.2008.02.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 02/21/2008] [Accepted: 02/26/2008] [Indexed: 10/22/2022]
Abstract
Design of clinically valuable antibacterial agents based upon naturally occurring peptides requires the use of spectroscopic methods, particularly NMR, to determine the three-dimensional structure of the native peptide so that analogues with improved therapeutic properties can be made. Ranatuerin-2CSa (GILSSFKGVAKGVAKDLAG KLLETLKCKITGC), first isolated from skin secretions of the Cascades frog, Rana cascadae, represents a promising candidate for drug development. The peptide shows potent growth inhibitory activity against Escherichia coli (MIC=5 microM) and Staphylococcus aureus (MIC=10 microM) but displays haemolytic activity against human erythrocytes (LC(50)=160 microM). The solution structure of ranatuerin-2CSa was investigated by proton NMR spectroscopy and molecular modelling. In aqueous solution, the peptide lacks secondary structure but, in a 2,2,2-trifluoroethanol (TFE-d(3))-H(2)O solvent mixture, the structure is characterised by a full length helix-turn-helix conformation between residues I(2)-L(21), L(22)-L(25) and K(26)-T(30) respectively. This structural information will facilitate the design of novel therapeutic agents based upon the ranatuerin-2CSa structure with improved antimicrobial potencies but decreased cytolytic activities against mammalian cells.
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Affiliation(s)
- Anusha P Subasinghage
- UCD School of Biomolecular and Biomedical Science, UCD Centre for Synthesis and Chemical Biology, UCD Conway institute, University College Dublin, Belfield, Dublin 4, Ireland
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Eley A, Ibrahim M, Kurdi SE, Conlon JM. Activities of the frog skin peptide, ascaphin-8 and its lysine-substituted analogs against clinical isolates of extended-spectrum beta-lactamase (ESBL) producing bacteria. Peptides 2008; 29:25-30. [PMID: 18068868 DOI: 10.1016/j.peptides.2007.10.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2007] [Revised: 10/27/2007] [Accepted: 10/30/2007] [Indexed: 11/19/2022]
Abstract
Extended-spectrum beta-lactamase (ESBL)-producing Gram-negative bacteria are becoming increasingly prevalent and their antibiotic resistance necessitates novel therapeutic intervention. Ascaphin-8 is a cationic alpha-helical peptide that shows broad-spectrum antibacterial activity but is also toxic to human erythrocytes (LC(50)= 55 microM). This study assesses the activity of ascaphin-8, and a series of l-lysine-substituted analogs, against a range of clinical isolates of ESBL-producing bacteria. All ESBL-producing Escherichia coli (MIC=1.5-6 microM) and Klebsiella pneumoniae (MIC=12.5-25 microM) strains tested were susceptible to ascaphin-8, as well as a group of miscellaneous ESBL-producing strains (Citrobacter, Salmonella, Serratia, Shigella spp.) (MIC< or = 25 microM). The Lys4- and Lys8-substituted analogs were generally the most potent against bacteria but showed the highest hemolytic activity. However, the Lys10, Lys14, and Lys18 analogs also displayed potent antibacterial activity while showing very low hemolytic activity (LC50> 500 microM). An unexpected finding was the susceptibility of ESBL-producing Proteus mirabilis strains to ascaphin-8 (MIC=12.5-25 microM) and its Lys4-substituted analog (MIC= 6 microM), although non-ESBL isolates of this organism were resistant to these peptides (MIC> 100 microM).
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Affiliation(s)
- Adrian Eley
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, United Arab Emirates University, 17666 Al Ain, United Arab Emirates
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Conlon JM, Abraham B, Galadari S, Knoop FC, Sonnevend A, Pál T. Antimicrobial and cytolytic properties of the frog skin peptide, kassinatuerin-1 and its L- and D-lysine-substituted derivatives. Peptides 2005; 26:2104-10. [PMID: 15885852 DOI: 10.1016/j.peptides.2005.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Revised: 04/09/2005] [Accepted: 04/11/2005] [Indexed: 11/19/2022]
Abstract
Kassinatuerin-1, a 21-amino-acid C-terminally alpha-amidated peptide first isolated from the skin of the African frog Kassina senegalensis, adopts an amphipathic alpha-helical conformation in a membrane-mimetic solvent (50% trifluoroethanol) and shows broad-spectrum antimicrobial activity. However, its therapeutic potential is limited by its relatively high cytolytic activity against mammalian cells. The antimicrobial and cytolytic properties of a peptide are determined by an interaction between cationicity, hydrophobicity, alpha-helicity and amphipathicity. Replacement of the C-terminal alpha-amide group in kassinatuerin-1 by carboxylic acid decreased both cationicity and alpha-helicity, resulting in an analog with decreased potency against Escherichia coli (4-fold) and Staphylococcus aureus (16-fold). Low cytolytic activities against human erythrocytes (LD50>400 microM) and L929 fibroblasts (LD50=105 microM) were also observed. Increasing cationicity, while maintaining amphipathic alpha-helical character, by progressively substituting Gly7, Ser18, and Asp19 on the hydrophilic face of the alpha-helix with L-lysine, increased antimicrobial potency against S. aureus and Candida albicans (up to 4-fold) but also increased hemolytic and cytolytic activities. In contrast, analogs with d-lysine at positions 7, 18 and 19 retained activity against Gram-negative bacteria but displayed reduced hemolytic and cytolytic activities. For example, the carboxylic acid derivative of [D-Lys7, D-Lys18, D-Lys19]kassinatuerin-1 was active (minimum inhibitory concentration (MIC)=6-12.5 microM) against a range of strongly antibiotic-resistant strains of E. coli but showed no detectable hemolytic activity at 400 microM and was 4-fold less cytolyic than kassinatuerin-1. However, the reduction in alpha-helicity produced by the D-amino acid substitutions resulted in analogs with reduced potencies against Gram-positive bacteria and against C. albicans.
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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, P.O. Box 17666, Al Ain, United Arab Emirates.
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Rollins-Smith LA, King JD, Nielsen PF, Sonnevend A, Conlon JM. An antimicrobial peptide from the skin secretions of the mountain chicken frog Leptodactylus fallax (Anura:Leptodactylidae). ACTA ACUST UNITED AC 2005; 124:173-8. [PMID: 15544856 DOI: 10.1016/j.regpep.2004.07.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2004] [Revised: 07/05/2004] [Accepted: 07/08/2004] [Indexed: 11/23/2022]
Abstract
A 25 amino-acid-residue, C-terminally alpha-amidated peptide with antimicrobial activity, which has been termed fallaxin, was isolated in high yield from the norepinephrine-stimulated skin secretions of the mountain chicken frog Leptodactylus fallax (Anura:Leptodactylidae). The amino acid sequence of the peptide (Gly-Val-Val-Asp-Ile-Leu-Lys-Gly-Ala-Ala-Lys-Asp-Ile-Ala-Gly-His-Leu-Ala-Ser-Lys-Val-Met-Asn-Lys-Leu.NH2) shows structural similarity with members of the ranatuerin-2 family previously isolated from the skins of frogs of the genus Rana that are only distantly related to the Leptodactylidae. This observation is consistent with the hypothesis that many frog skin antimicrobial peptides are related evolutionarily, having arisen from multiple duplications of an ancestral gene that existed before the radiation of the different families. Fallaxin inhibited the growth of reference strains of Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Enterobacter cloacae, Klebsiella pneumoniae) but with relatively low potency (MIC> or =20 microM) and was inactive against the Gram-positive bacterium (Staphylococcus aureus) and the yeast Candida albicans. The hemolytic activity of fallaxin was very low (HC50>200 microM). A second peptide, comprising residues (1-22) of fallaxin, was also isolated from the skin secretions but this component was inactive against the microorganisms tested.
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Affiliation(s)
- Louise A Rollins-Smith
- Departments of Microbiology and Immunology and of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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14
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Pál T, Sonnevend A, Galadari S, Conlon JM. Design of potent, non-toxic antimicrobial agents based upon the structure of the frog skin peptide, pseudin-2. ACTA ACUST UNITED AC 2005; 129:85-91. [PMID: 15927702 DOI: 10.1016/j.regpep.2005.01.015] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2004] [Revised: 01/01/2005] [Accepted: 01/27/2005] [Indexed: 11/15/2022]
Abstract
Pseudin-2, a naturally occurring 24 amino-acid-residue antimicrobial peptide first isolated from the skin of the South American paradoxical frog Pseudis paradoxa, has weak hemolytic and cytolytic activity but also relatively low potency against microorganisms. In a membrane-mimetic environment, the peptide exists in an amphipathic alpha-helical conformation. Analogs of the peptide with increased cationicity and alpha-helicity were chemically synthesized by progressively substituting neutral and acidic amino acid residues on the hydrophilic face of the alpha-helix by lysine. Analogs with up to three L-lysine substitutions showed increased potency against a range of gram-negative and gram-positive bacteria (up to 16-fold) whilst retaining low hemolytic activity. The analog [D-Lys3, D-Lys10, D-Lys14]pseudin-2 showed potent activity against gram-negative bacteria (minimum inhibitory concentration, MIC=5 microM against several antibiotic-resistant strains of Escherichia coli) but very low hemolytic activity (HC50>500 microM) and cytolytic activity against L929 fibroblasts (LC50=215 microM). Increasing the number of l-lysines to four and five did not enhance antimicrobial potency further but increased hemolytic activity towards human erythrocytes. Time-kill studies demonstrated that the analog [Lys3, Lys10, Lys14, Lys21]pseudin-2 at a concentration of 1 x MIC was bacteriocidal against E. coli (99.9% cell death after 96 min) but was bacteriostatic against S. aureus. Increasing the hydrophobicity of pseudin-2, while maintaining the amphipathic character of the molecule, by substitution of neutral amino acids on the hydrophobic face of the alpha-helix by L-phenylalanine, had only minor effects on antimicrobial and hemolytic activities.
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Affiliation(s)
- Tibor Pál
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666 Al-Ain, United Arab Emirates
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Conlon JM, Sonnevend A, Davidson C, Demandt A, Jouenne T. Host-defense peptides isolated from the skin secretions of the Northern red-legged frog Rana aurora aurora. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2005; 29:83-90. [PMID: 15325526 DOI: 10.1016/j.dci.2004.05.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2004] [Revised: 04/25/2004] [Accepted: 05/04/2004] [Indexed: 05/24/2023]
Abstract
Antimicrobial peptides in the skin secretions of anurans constitute a component of the innate immunity that protects the organism against invading pathogens. Four peptides with antimicrobial activity were isolated in high yield from norepinephrine-stimulated skin secretions of the Northern red-legged frog Rana aurora aurora and their primary structures determined. Ranatuerin-2AUa (GILSSFKGVAKGVAKNLAGKLLDELKCKITGC) showed potent growth-inhibitory activity against a range of Gram-positive and Gram-negative bacteria (minimum inhibitory concentrations < 20 microM) but low hemolytic activity against human erythrocytes (50% hemolysis at 290 microM). Brevinin-1AUa (FLPILAGLAAKLVPKVFCSITKKC) and brevinin-1AUb (FLPILAGLAANILPKVFCSITKKC) also showed potent antimicrobial activity but were strongly hemolytic (HC50 < 10 microM). Temporin-1AUa (FLPIIGQLLSGLL.NH2) atypically lacked a basic amino acid residue and showed very weak antimicrobial and hemolytic activity. Its biological function remains to be established. The primary structures of the antimicrobial peptides are consistent with a close phylogenetic relationship between R. aurora, Rana boylii and Rana luteiventris.
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Affiliation(s)
- J Michael Conlon
- Department of Biochemistry, Faculty of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al-Ain, United Arab Emirates.
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Conlon JM, Sonnevend A, Davidson C, Smith DD, Nielsen PF. The ascaphins: a family of antimicrobial peptides from the skin secretions of the most primitive extant frog, Ascaphus truei. Biochem Biophys Res Commun 2004; 320:170-5. [PMID: 15207717 DOI: 10.1016/j.bbrc.2004.05.141] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Indexed: 11/18/2022]
Abstract
The tailed frog Ascaphus truei occupies a unique position in phylogeny as the most primitive extant anuran and is regarded as the sister taxon to the clade of all other living frogs. Eight structurally related peptides, termed ascaphins 1-8, were isolated from norepinephrine-stimulated skin secretions of A. truei and were shown to possess differential growth inhibitory activity against Escherichia coli and Staphylococcus aureus. Ascaphins 2-7 may be represented by the consensus amino acid sequence GX2DX2KGAAKX3KTVAX2IANX.COOH whereas ascaphin-1 (GFRDVLKGAAKAFVKTVAGHIAN.NH2) and ascaphin-8 (GFKDLLKGAAKALVKTVLF.NH2) contain a C-terminally alpha-amidated residue. The ascaphins show no appreciable structural similarity with other families of antimicrobial peptides from frog skin but display limited sequence identity with the cationic, amphipathic alpha-helical peptides pandinin 1 and opistoporin 1, isolated from the venoms of African scorpions. Ascaphin-8 shows the highest potency against a range of pathogenic microorganisms but has the greatest haemolytic activity. The data indicate that the host defence strategy of using antimicrobial peptides in skin secretions arose early in the evolution of anurans.
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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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