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Gan BH, Gaynord J, Rowe SM, Deingruber T, Spring DR. The multifaceted nature of antimicrobial peptides: current synthetic chemistry approaches and future directions. Chem Soc Rev 2021; 50:7820-7880. [PMID: 34042120 PMCID: PMC8689412 DOI: 10.1039/d0cs00729c] [Citation(s) in RCA: 165] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Indexed: 12/13/2022]
Abstract
Bacterial infections caused by 'superbugs' are increasing globally, and conventional antibiotics are becoming less effective against these bacteria, such that we risk entering a post-antibiotic era. In recent years, antimicrobial peptides (AMPs) have gained significant attention for their clinical potential as a new class of antibiotics to combat antimicrobial resistance. In this review, we discuss several facets of AMPs including their diversity, physicochemical properties, mechanisms of action, and effects of environmental factors on these features. This review outlines various chemical synthetic strategies that have been applied to develop novel AMPs, including chemical modifications of existing peptides, semi-synthesis, and computer-aided design. We will also highlight novel AMP structures, including hybrids, antimicrobial dendrimers and polypeptides, peptidomimetics, and AMP-drug conjugates and consider recent developments in their chemical synthesis.
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Affiliation(s)
- Bee Ha Gan
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
| | - Josephine Gaynord
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
| | - Sam M Rowe
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
| | - Tomas Deingruber
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
| | - David R Spring
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
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2
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Yu W, Ning N, Xue Y, Huang Y, Guo F, Li T, Yang B, Luo D, Sun Y, Li Z, Wang J, He Z, Cheng S, Zhang X, Wang H. A Chimeric Cationic Peptide Composed of Human β-Defensin 3 and Human β-Defensin 4 Exhibits Improved Antibacterial Activity and Salt Resistance. Front Microbiol 2021; 12:663151. [PMID: 34025617 PMCID: PMC8137984 DOI: 10.3389/fmicb.2021.663151] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/14/2021] [Indexed: 01/10/2023] Open
Abstract
Human beta-defensins (hBDs) play an important role in the host defense against various microbes, showing different levels of antibacterial activity and salt resistance in vitro. It is of interest to investigate whether can chimeric hBD analogs enhanced antibacterial activity and salt resistance. In this study, we designed a chimeric human defensin, named H4, by combining sequences of human beta-defensin-3 (hBD-3) and human beta-defensin-4 (hBD-4), then evaluated its antibacterial activity, salt resistance, and cytotoxic effects. The result showed that the antibacterial activity of H4 against most tested strains, including Klebsiella pneumonia, Enterococcus faecalis, Staphyloccocus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, and Acinetobacter baumannii was significantly improved compared to that of hBD-3 and hBD-4. Notably, H4 exhibited significantly better antibacterial activity against multidrug resistant isolate A. baumannii MDR-ZJ06 than commonly used antibiotics. Chimeric H4 still showed more than 80% antibacterial activity at high salt concentration (150 μM), which proves its good salt tolerance. The cytotoxic effect assay showed that the toxicity of H4 to Hela, Vero, A549 cells and erythrocytes at a low dose (<10 μg/ml) was similar to that of hBD-3 and hBD-4. In conclusion, given its broad spectrum of antibacterial activity and high salt resistance, chimeric H4 could serve as a promising template for new therapeutic antimicrobial agents.
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Affiliation(s)
- Wenjing Yu
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Nianzhi Ning
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Ying Xue
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,College of Life Science, Ludong University, Yantai, China
| | - Yanyu Huang
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Feng Guo
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Tao Li
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Boning Yang
- Department of Orthopedics, Henan University People's Hospital, Zhengzhou, China
| | - Deyan Luo
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yakun Sun
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zhan Li
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Jianxin Wang
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zhili He
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Shiwei Cheng
- College of Life Science, Ludong University, Yantai, China
| | - Xingxiao Zhang
- College of Life Science, Ludong University, Yantai, China
| | - Hui Wang
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
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3
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Kapil S, Sharma V. d-Amino acids in antimicrobial peptides: a potential approach to treat and combat antimicrobial resistance. Can J Microbiol 2020; 67:119-137. [PMID: 32783775 DOI: 10.1139/cjm-2020-0142] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Antimicrobial resistance is one of the leading challenges in the human healthcare segment. Advances in antimicrobial resistance have triggered exploration of natural alternatives to stabilize its seriousness. Antimicrobial peptides are small, positively charged oligopeptides that are as potent as commercially available antibiotics against a wide spectrum of organisms, such as Gram-positive bacteria, Gram-negative bacteria, viruses, and fungal strains. In addition to their antibiotic capabilities, these peptides possess anticancer activity, activate the immune response, and regulate inflammation. Peptides have distinct modes of action and fall into various categories due to their amino acid composition. Although antimicrobial peptides specifically target the bacterial cytoplasmic membrane, they can also target the cell nucleus and protein synthesis. Owing to the increasing demand for novel treatments against the threat of antimicrobial resistance, naturally synthesized peptides are a beneficial development concept. Antimicrobial peptides are pervasive and can easily be modified using de-novo synthesis technology. Antimicrobial peptides can be isolated from natural resources such as humans, plants, bacteria, and fungi. This review gives a brief overview of antimicrobial peptides and their diastereomeric composition. Other current trends, the future scope of antimicrobial peptides, and the role of d-amino acids are also discussed, with a specific emphasis on the design and development of new drugs.
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Affiliation(s)
- Shikha Kapil
- University Institute of Biotechnology, Chandigarh University, Gharuan Mohali, Punjab 140413, India.,University Institute of Biotechnology, Chandigarh University, Gharuan Mohali, Punjab 140413, India
| | - Vipasha Sharma
- University Institute of Biotechnology, Chandigarh University, Gharuan Mohali, Punjab 140413, India.,University Institute of Biotechnology, Chandigarh University, Gharuan Mohali, Punjab 140413, India
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4
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Hazam PK, Akhil R, Jerath G, Saikia J, Ramakrishnan V. Topological effects on the designability and bactericidal potency of antimicrobial peptides. Biophys Chem 2019; 248:1-8. [DOI: 10.1016/j.bpc.2019.02.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 02/22/2019] [Accepted: 02/22/2019] [Indexed: 12/21/2022]
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5
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Hazam PK, Goyal R, Ramakrishnan V. Peptide based antimicrobials: Design strategies and therapeutic potential. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 142:10-22. [PMID: 30125585 DOI: 10.1016/j.pbiomolbio.2018.08.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 08/13/2018] [Accepted: 08/14/2018] [Indexed: 12/24/2022]
Abstract
Therapeutic activity of antibiotics is noteworthy, as they are used in the treatment of microbial infections. Regardless of their utility, there has been a steep decrease in the number of drug candidates due to antibiotic resistance, an inevitable consequence of noncompliance with the full therapeutic regimen. A variety of resistant species like MDR (Multi-Drug Resistant), XDR (Extensively Drug-Resistant) and PDR (Pan Drug-Resistant) species have evolved, but discovery pipeline has already shown signs of getting dried up. Therefore, the need for newer antibiotics is of utmost priority to combat the microbial infections of future times. Peptides have some interesting features like minimal side effect, high tolerability and selectivity towards specific targets, which would help them successfully comply with the stringent safety standards set for clinical trials. In this review, we attempt to present the state of the art in the discovery of peptide-based antimicrobials from a design perspective.
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Affiliation(s)
- Prakash Kishore Hazam
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Guwahati, 781039, India
| | - Ruchika Goyal
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Guwahati, 781039, India
| | - Vibin Ramakrishnan
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Guwahati, 781039, India.
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6
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Bactericidal Potency and Extended Serum Life of Stereo-Chemically Engineered Peptides Against Mycobacterium. Int J Pept Res Ther 2018. [DOI: 10.1007/s10989-018-9690-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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7
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Pachón-Ibáñez ME, Smani Y, Pachón J, Sánchez-Céspedes J. Perspectives for clinical use of engineered human host defense antimicrobial peptides. FEMS Microbiol Rev 2018; 41:323-342. [PMID: 28521337 PMCID: PMC5435762 DOI: 10.1093/femsre/fux012] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 02/28/2017] [Indexed: 12/15/2022] Open
Abstract
Infectious diseases caused by bacteria, viruses or fungi are among the leading causes of death worldwide. The emergence of drug-resistance mechanisms, especially among bacteria, threatens the efficacy of all current antimicrobial agents, some of them already ineffective. As a result, there is an urgent need for new antimicrobial drugs. Host defense antimicrobial peptides (HDPs) are natural occurring and well-conserved peptides of innate immunity, broadly active against Gram-negative and Gram-positive bacteria, viruses and fungi. They also are able to exert immunomodulatory and adjuvant functions by acting as chemotactic for immune cells, and inducing cytokines and chemokines secretion. Moreover, they show low propensity to elicit microbial adaptation, probably because of their non-specific mechanism of action, and are able to neutralize exotoxins and endotoxins. HDPs have the potential to be a great source of novel antimicrobial agents. The goal of this review is to provide an overview of the advances made in the development of human defensins as well as the cathelicidin LL-37 and their derivatives as antimicrobial agents against bacteria, viruses and fungi for clinical use.
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Affiliation(s)
- María Eugenia Pachón-Ibáñez
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville
| | - Younes Smani
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville
| | - Jerónimo Pachón
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville.,Department of Medicine, University of Seville, Seville, Spain
| | - Javier Sánchez-Céspedes
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville.,Department of Medicine, University of Seville, Seville, Spain
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8
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Gomes B, Augusto MT, Felício MR, Hollmann A, Franco OL, Gonçalves S, Santos NC. Designing improved active peptides for therapeutic approaches against infectious diseases. Biotechnol Adv 2018; 36:415-429. [PMID: 29330093 DOI: 10.1016/j.biotechadv.2018.01.004] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 12/13/2017] [Accepted: 01/06/2018] [Indexed: 12/25/2022]
Abstract
Infectious diseases are one of the main causes of human morbidity and mortality. In the last few decades, pathogenic microorganisms' resistance to conventional drugs has been increasing, and it is now pinpointed as a major worldwide health concern. The need to search for new therapeutic options, as well as improved treatment outcomes, has therefore increased significantly, with biologically active peptides representing a new alternative. A substantial research effort is being dedicated towards their development, especially due to improved biocompatibility and target selectivity. However, the inherent limitations of peptide drugs are restricting their application. In this review, we summarize the current status of peptide drug development, focusing on antiviral and antimicrobial peptide activities, highlighting the design improvements needed, and those already being used, to overcome the drawbacks of the therapeutic application of biologically active peptides.
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Affiliation(s)
- Bárbara Gomes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Marcelo T Augusto
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Mário R Felício
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Axel Hollmann
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal; Laboratory of Molecular Microbiology, Institute of Basic and Applied Microbiology, National University of Quilmes, Bernal, Buenos Aires, Argentina; Laboratory of Biointerfaces and Biomimetic Systems, CITSE, National University of Santiago del Estero-CONICET, Santiago del Estero, Argentina
| | - Octávio L Franco
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil; Programa de Pós-Graduação em Patologia Molecular, Universidade de Brasília, Brasília, DF, Brazil; S-Inova Biotech, Pós-graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil
| | - Sónia Gonçalves
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Nuno C Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal.
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9
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Kudryashova E, Seveau SM, Kudryashov DS. Targeting and inactivation of bacterial toxins by human defensins. Biol Chem 2017; 398:1069-1085. [PMID: 28593905 DOI: 10.1515/hsz-2017-0106] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 04/18/2017] [Indexed: 11/15/2022]
Abstract
Defensins, as a prominent family of antimicrobial peptides (AMP), are major effectors of the innate immunity with a broad range of immune modulatory and antimicrobial activities. In particular, defensins are the only recognized fast-response molecules that can neutralize a broad range of bacterial toxins, many of which are among the deadliest compounds on the planet. For a decade, the mystery of how a small and structurally conserved group of peptides can neutralize a heterogeneous group of toxins with little to no sequential and structural similarity remained unresolved. Recently, it was found that defensins recognize and target structural plasticity/thermodynamic instability, fundamental physicochemical properties that unite many bacterial toxins and distinguish them from the majority of host proteins. Binding of human defensins promotes local unfolding of the affected toxins, destabilizes their secondary and tertiary structures, increases susceptibility to proteolysis, and leads to their precipitation. While the details of toxin destabilization by defensins remain obscure, here we briefly review properties and activities of bacterial toxins known to be affected by or resilient to defensins, and discuss how recognized features of defensins correlate with the observed inactivation.
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10
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Mathew B, Olli S, Guru A, Nagaraj R. Chimeric analogs of human β-defensin 1 and θ-defensin disrupt pre-established bacterial biofilms. Bioorg Med Chem Lett 2017. [PMID: 28642103 DOI: 10.1016/j.bmcl.2017.06.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Antibiofilm activity of several human defensin analogs that have the ability to kill planktonic bacteria, against pre-established biofilms of Escherichia coli MG1655 and Staphylococcus aureus NCTC 8530 were examined. Linear and linear fatty acylated analogs did not show any activity while disulfide constrained analogs disrupted pre-established S. aureus biofilms. Chimeric analogs of human β-defensin 1 and θ-defensin, hBTD-1 and [d]hBTD-1 were highly active against S. aureus biofilms. Among the analogs tested, only the d-enantiomer [d]hBTD-1 showed activity against E. coli biofilm. Our study provides insights into the structural requirements for the eradication of pre-established biofilms in defensin analogs.
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Affiliation(s)
- Basil Mathew
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.
| | - Sudar Olli
- Virupaksha Life Sciences Pvt Ltd, CRTDH, CSIR-Centre for Cellular and Molecular Biology Annexe-II, Hyderabad 500 007, India
| | - Ankeeta Guru
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Ramakrishanan Nagaraj
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.
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11
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Zhu X, Zhang L, Wang J, Ma Z, Xu W, Li J, Shan A. Characterization of antimicrobial activity and mechanisms of low amphipathic peptides with different α-helical propensity. Acta Biomater 2015; 18:155-67. [PMID: 25735802 DOI: 10.1016/j.actbio.2015.02.023] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 01/14/2015] [Accepted: 02/23/2015] [Indexed: 11/29/2022]
Abstract
Antimicrobial peptides (AMPs) serve as a defense mechanism within multicellular organisms and are attracting increasing attention because of their potential application in the treatment of multidrug-resistant infections. Amphipathicity has long been believed to be the most important consideration for the structural modification and design of both naturally occurring and synthetic AMPs. Previous studies indicated that disruptive amphipathicity formed by replacing the paired charged amino acid residues on the polar face of an amphipathic helix with tryptophan residues linked with hydrogen bonds on the basis of α-helical protein folding principles endowed the AMPs with increased cell selectivity. In an attempt to augment and hone this strategy further, we designed a series of imperfect amphipathic peptides by placing different types of amino acid residues at the hydrogen bond linked positions of α-helix structures to characterize their antimicrobial properties and mechanism of action. The d-Trp-substituted sequence (PRW4-d) showed greater antimicrobial potency than Cys-(C4), Asp-(D4), Ile-(I4), and Pro-(P4) substituted sequences, comparable to the l-Trp-substituted parent sequence (PRW4). Furthermore, the total replacement of Lys residues with Arg residues along the peptide sequence (PRW4-R) exhibited enhanced antimicrobial activity and cell selectivity. In addition, no cytotoxicity was observed among these synthetic peptides. PRW4-d and PRW4-R maintained their activities in the presence of physiological salts and human serum. The fluorescence spectroscopy, flow cytometry, and electron microscopy observations indicated that the optimized sequences exhibited excellent antimicrobial potency by inducing cytoplasmic membrane potential loss, membrane permeabilization and disruption. Collectively, the results could be useful for designing short AMPs with great antimicrobial activity and cell selectivity.
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Affiliation(s)
- Xin Zhu
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
| | - Licong Zhang
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
| | - Jue Wang
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
| | - Zhi Ma
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
| | - Wei Xu
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
| | - Jianping Li
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
| | - Anshan Shan
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China.
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12
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Sharma H, Mathew B, Nagaraj R. Engineering of a linear inactive analog of human β-defensin 4 to generate peptides with potent antimicrobial activity. J Pept Sci 2015; 21:501-11. [PMID: 25810238 DOI: 10.1002/psc.2770] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 02/12/2015] [Accepted: 02/13/2015] [Indexed: 02/01/2023]
Abstract
Human β-defensins (HBDs) are cationic antimicrobial peptides constrained by three disulfide bridges. They have diverse range of functions in the innate immune response. It is of interest to investigate whether linear analogs of defensins can be generated, which possess antimicrobial activity. In this study, we have designed linear peptides with potent antimicrobial activity from an inactive peptide spanning the N-terminus of HBD4. Our results show that l-arginine to d-arginine substitution imparts considerable antimicrobial activity against both bacteria and Candida albicans. Increase in hydrophobicity by fatty acylation of the peptides with myristic acid further enhances their potency. In the presence of high concentrations of salt, antimicrobial activity of the myristoylated peptide with l-arginine is attenuated relatively to a lesser extent as compared with the linear active peptide with d-arginine. Substitution of cysteine with the hydrophobic helix-promoting amino acid α-aminoisobutyric acid favors candidacidal activity but not antibacterial activity. The mechanism of killing by d-arginine substituted unacylated analog involves transient interaction with the bacterial membrane followed by translocation into the cytoplasm without membrane permeabilization. Accumulation of peptides in the cytoplasm can affect various cellular processes that lead to cell death. However, the peptide causes membrane permeabilization in case of C. albicans. Myristoylation results in greater interaction of the peptide chain with the microbial cell surface and causes membrane permeabilization. Results described in the study demonstrate that it is possible to generate highly active linear analogs of defensins by selective introduction of d-amino acids and fatty acids, which could be attractive candidates for development as therapeutic agents.
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Affiliation(s)
- Himanshu Sharma
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India
| | - Basil Mathew
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India
| | - Ramakrishnan Nagaraj
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India
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13
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Chakraborty S, Rao B, Dandekar A. PAGAL - Properties and corresponding graphics of alpha helical structures in proteins. F1000Res 2014; 3:206. [PMID: 25352981 PMCID: PMC4207245 DOI: 10.12688/f1000research.4952.2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/17/2014] [Indexed: 11/20/2022] Open
Abstract
Alpha helices (AH) are peptide fragments characterized by regular patterns of hydrogen bonding between the carbonyl oxygen and amino nitrogen of residues regularly spaced in sequence, resulting in spiral conformations. Their preponderance in protein structures underlines their importance. Interestingly, AHs are present in most anti-microbial peptides, although they might remain in random-coil conformations depending on the solvent dielectric. For example, the cecropin component of the chimeric anti-microbial protein designed previously by our group comprises of two AHs linked by a short stretch of random coil. These anti-microbial peptides are often amphipathic (quantified by a hydrophobic moment), aligning hydrophobic residues on one surface and charged residues on the others. In the current work, we reproduce previously described computational methods to compute the hydrophobic moment of AHs - and provide open access to the source code (PAGAL). We simultaneously generated input files for TikZ (a package for creating high resolution graphics programmatically) to obtain the Edmundson wheel and showing the direction and magnitude of the hydrophobic moment, and Pymol scripts to generate color coded protein surfaces. Additionally, we have observed an empirical structural property of AHs: the distance between the Cα atoms of the ith and (i+4)th residue is equal to the distance between the carbonyl oxygens of the ith and (i+4)th residue. We validated this using 100 non-homologous high resolution structures from the PISCES database. The source code and manual is available at http://github.com/sanchak/pagal and on http://dx.doi.org/10.5281/zenodo.11136.
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Affiliation(s)
- Sandeep Chakraborty
- Plant Sciences Department, University of California, Davis, 95616, USA ; Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, 400 005, India
| | - Basuthkar Rao
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, 400 005, India
| | - Abhaya Dandekar
- Plant Sciences Department, University of California, Davis, 95616, USA
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14
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A hybrid cationic peptide composed of human β-defensin-1 and humanized θ-defensin sequences exhibits salt-resistant antimicrobial activity. Antimicrob Agents Chemother 2014; 59:217-25. [PMID: 25348533 DOI: 10.1128/aac.03901-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have designed a hybrid peptide by combining sequences of human β-defensin-1 (HBD-1) and θ-defensin, in an attempt to generate a molecule that combines the diversity in structure and biological activity of two different peptides to yield a promising therapeutic candidate. HBD-1 was chosen as it is a natural defensin of humans that is constitutively expressed, but its antibacterial activity is considerably impaired by elevated ionic strength. θ-Defensins are expressed in human bone marrow as a pseudogene and are homologous to rhesus monkey circular minidefensins. Retrocyclins are synthetic human θ-defensins. The cyclic nature of the θ-defensin peptides makes them salt resistant, nonhemolytic, and virtually noncytotoxic in vitro. However, a nonhuman circular molecule developed for clinical use would be less viable than a linear molecule. In this study, we have fused the C-terminal region of HBD-1 to the nonapeptide sequence of a synthetic retrocyclin. Cyclization was achieved by joining the terminal ends of the hybrid peptide by a disulfide bridge. The hybrid peptide with or without the disulfide bridge exhibited enhanced antimicrobial activity against both Gram-negative and Gram-positive bacteria as well as against fungi, including clinical bacterial isolates from eye infections. The peptide retained activity in the presence of NaCl and serum and was nonhemolytic in vitro. Thus, the hybrid peptide generated holds potential as a new class of antibiotics.
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15
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Masso-Silva JA, Diamond G. Antimicrobial peptides from fish. Pharmaceuticals (Basel) 2014; 7:265-310. [PMID: 24594555 PMCID: PMC3978493 DOI: 10.3390/ph7030265] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/06/2014] [Accepted: 02/18/2014] [Indexed: 12/21/2022] Open
Abstract
Antimicrobial peptides (AMPs) are found widely distributed through Nature, and participate in the innate host defense of each species. Fish are a great source of these peptides, as they express all of the major classes of AMPs, including defensins, cathelicidins, hepcidins, histone-derived peptides, and a fish-specific class of the cecropin family, called piscidins. As with other species, the fish peptides exhibit broad-spectrum antimicrobial activity, killing both fish and human pathogens. They are also immunomodulatory, and their genes are highly responsive to microbes and innate immuno-stimulatory molecules. Recent research has demonstrated that some of the unique properties of fish peptides, including their ability to act even in very high salt concentrations, make them good potential targets for development as therapeutic antimicrobials. Further, the stimulation of their gene expression by exogenous factors could be useful in preventing pathogenic microbes in aquaculture.
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Affiliation(s)
- Jorge A Masso-Silva
- Department of Pediatrics and Graduate School of Biomedical Sciences, Rutgers New Jersey Medical School, Newark, NJ 07101, USA.
| | - Gill Diamond
- Department of Oral Biology, University of Florida, Box 100424, Gainesville, FL 32610, USA.
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