101
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Sim S, Wang P, Beyer BN, Cutrona KJ, Radhakrishnan ML, Elmore DE. Investigating the nucleic acid interactions of histone-derived antimicrobial peptides. FEBS Lett 2017; 591:706-717. [PMID: 28130840 DOI: 10.1002/1873-3468.12574] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/13/2017] [Accepted: 01/22/2017] [Indexed: 11/05/2022]
Abstract
While many antimicrobial peptides (AMPs) disrupt bacterial membranes, some translocate into bacteria and interfere with intracellular processes. Buforin II and DesHDAP1 are thought to kill bacteria by interacting with nucleic acids. Here, molecular modeling and experimental measurements are used to show that neither nucleic acid binding peptide selectively binds DNA sequences. Simulations and experiments also show that changing lysines to arginines enhances DNA binding, suggesting that including additional guanidinium groups is a potential strategy to engineer more potent AMPs. Moreover, the lack of binding specificity may make it more difficult for bacteria to evolve resistance to these and other similar AMPs.
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Affiliation(s)
- Sukin Sim
- Department of Chemistry, Wellesley College, MA, USA
| | - Penny Wang
- Department of Chemistry, Wellesley College, MA, USA
| | | | | | - Mala L Radhakrishnan
- Department of Chemistry, Wellesley College, MA, USA.,Biochemistry Program, Wellesley College, MA, USA
| | - Donald E Elmore
- Department of Chemistry, Wellesley College, MA, USA.,Biochemistry Program, Wellesley College, MA, USA
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102
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Fojan P, Gurevich L. Atomic Force Microscopy Study of the Interactions of Indolicidin with Model Membranes and DNA. Methods Mol Biol 2017; 1548:201-215. [PMID: 28013506 DOI: 10.1007/978-1-4939-6737-7_14] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The cell membrane is the first barrier and quite often the primary target that antimicrobial peptides (AMPs) have to destroy or penetrate to fulfill their mission. Upon penetrating through the membrane, the peptides can further attack intracellular targets, in particular DNA. Studying the interaction of an antimicrobial peptide with a cell membrane and DNA holds keys to understanding its killing mechanisms. Commonly, these interactions are studied by using optical or scanning electron microscopy and appropriately labeled peptides. However, labeling can significantly affect the hydrophobicity, conformation, and size of the peptide, hence altering the interaction significantly. Here, we describe the use of atomic force microscopy (AFM) for a label-free study of the interactions of peptides with model membranes under physiological conditions and DNA as a possible intracellular target.
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Affiliation(s)
- Peter Fojan
- Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4A, Aalborg, 9220, Denmark.
| | - Leonid Gurevich
- Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4A, Aalborg, 9220, Denmark
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103
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He SW, Zhang J, Li NQ, Zhou S, Yue B, Zhang M. A TFPI-1 peptide that induces degradation of bacterial nucleic acids, and inhibits bacterial and viral infection in half-smooth tongue sole, Cynoglossus semilaevis. FISH & SHELLFISH IMMUNOLOGY 2017; 60:466-473. [PMID: 27840169 DOI: 10.1016/j.fsi.2016.11.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/04/2016] [Accepted: 11/09/2016] [Indexed: 06/06/2023]
Abstract
Tissue factor pathway inhibitor 1 (TFPI-1) is a serine protease inhibitor that inhibits tissue factor (TF)-mediated coagulation. The C-terminal region of TFPI-1 could be cleaved off and proved to be antimicrobial against a broad-spectrum of microorganism. In a previous study, a C-terminal peptide, TC24 (with 24 amino acids), derived from tongue sole (Cynoglossus semilaevis) TFPI-1, was synthesized and found antibacterial against Micrococcus luteus. In the present study, the antibacterial spectrum and the action mode of TC24 was further examined, and its in vivo function was analyzed. Our results showed that TC24 also possesses bactericidal activity against Staphylococcus aureus and Vibrio vulnificus. During its interaction with the target bacterial cells, TC24 destroyed cell membrane integrity, penetrated into the cytoplasm, and induced degradation of genomic DNA and total RNA. In vivo study showed that administration of tongue sole with TC24 before bacterial and viral infection significantly reduced pathogen dissemination and replication in tissues. These results indicated that TC24 is a novel antimicrobial peptide against bacterial and viral pathogens, and that the observed effect of TC24 on bacterial RNA adds new insights to the action mechanism of fish antimicrobial peptides. Moreover, TC24 may play an important role in fighting pathogenic infection in aquaculture.
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Affiliation(s)
- Shu-Wen He
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Jian Zhang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Ning-Qiu Li
- Key Laboratory of Fishery Drug Development, Ministry of Agriculture, Key Laboratory of Aquatic Animal Immune Technology, Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510380, China
| | - Shun Zhou
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Bin Yue
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Min Zhang
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China.
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104
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Barreto-Santamaría A, Curtidor H, Arévalo-Pinzón G, Herrera C, Suárez D, Pérez WH, Patarroyo ME. A New Synthetic Peptide Having Two Target of Antibacterial Action in E. coli ML35. Front Microbiol 2016; 7:2006. [PMID: 28066341 PMCID: PMC5167725 DOI: 10.3389/fmicb.2016.02006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 11/30/2016] [Indexed: 11/13/2022] Open
Abstract
The increased resistance of microorganisms to the different antimicrobials available to today has highlighted the need to find new therapeutic agents, including natural and/or synthetic antimicrobial peptides (AMPs). This study has evaluated the antimicrobial activity of synthetic peptide 35409 (RYRRKKKMKKALQYIKLLKE) against Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa ATCC 15442 and Escherichia coli ML 35 (ATCC 43827). The results have shown that peptide 35409 inhibited the growth of these three bacterial strains, having 16-fold greater activity against E. coli and P. aeruginosa, but requiring less concentration regarding E. coli (22 μM). When analyzing this activity against E. coli compared to time taken, it was found that this peptide inhibited bacterial growth during the first 60 min and reduced CFU/mL 1 log after 120 min had elapsed. This AMP permeabilized the E. coli membrane by interaction with membrane phospholipids, mainly phosphatidylethanolamine, inhibited cell division and induced filamentation, suggesting two different targets of action within a bacterial cell. Cytotoxicity studies revealed that peptide 35409 had low hemolytic activity and was not cytotoxic for two human cell lines. We would thus propose, in the light of these findings, that the peptide 35409 sequence should provide a promising template for designing broad-spectrum AMPs.
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Affiliation(s)
- Adriana Barreto-Santamaría
- Receptor-Ligand Department, Fundación Instituto de Inmunología de ColombiaBogotá, Colombia; Faculty of Sciences and Education, Universidad Distrital Francisco José de CaldasBogotá, Colombia; School of Medicine and Health sciences, Universidad del RosarioBogotá, Colombia
| | - Hernando Curtidor
- Receptor-Ligand Department, Fundación Instituto de Inmunología de ColombiaBogotá, Colombia; School of Medicine and Health sciences, Universidad del RosarioBogotá, Colombia
| | - Gabriela Arévalo-Pinzón
- Receptor-Ligand Department, Fundación Instituto de Inmunología de ColombiaBogotá, Colombia; School of Medicine and Health sciences, Universidad del RosarioBogotá, Colombia
| | - Chonny Herrera
- Receptor-Ligand Department, Fundación Instituto de Inmunología de ColombiaBogotá, Colombia; School of Medicine and Health sciences, Universidad del RosarioBogotá, Colombia
| | - Diana Suárez
- Receptor-Ligand Department, Fundación Instituto de Inmunología de ColombiaBogotá, Colombia; School of Medicine and Health sciences, Universidad del RosarioBogotá, Colombia
| | - Walter H Pérez
- Escuela Colombiana de Carreras Industriales Bogotá, Colombia
| | - Manuel E Patarroyo
- Receptor-Ligand Department, Fundación Instituto de Inmunología de ColombiaBogotá, Colombia; Faculty of Medicine, Universidad Nacional de ColombiaBogotá, Colombia
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105
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Starr CG, He J, Wimley WC. Host Cell Interactions Are a Significant Barrier to the Clinical Utility of Peptide Antibiotics. ACS Chem Biol 2016; 11:3391-3399. [PMID: 27797468 DOI: 10.1021/acschembio.6b00843] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Despite longstanding promise and many known examples, antimicrobial peptides (AMPs) have failed, thus far, to impact human medicine. On the basis of the physical chemistry and mechanism of action of AMPs, we hypothesized that host cell interactions could contribute to a loss of activity in vivo where host cells are highly concentrated. To test this idea, we characterized AMP activity in the presence of human red blood cells (RBC). Indeed, we show that most of a representative set of natural and synthetic AMPs tested are significantly inhibited by preincubation with host cells and would be effectively inactive at physiological cell density. We studied an example broad-spectrum AMP, ARVA (RRGWALRLVLAY), in a direct, label-free binding assay. We show that weak binding to host cells, coupled with their high concentration, is sufficient to account for a loss of useful activity, for at least some AMPs, because >1 × 108 peptides must be bound to each bacterial cell to achieve sterilization. The effect of host cell preincubation on AMP activity is comparable to that of serum protein binding. Feasible changes in host cell binding could lead to AMPs that do not lose activity through interaction with host cells. We suggest that the intentional identification of AMPs that are active in the presence of concentrated host cells can be achieved with a paradigm shift in the way AMPs are discovered.
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Affiliation(s)
- Charles G. Starr
- Department of Biochemistry
and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana 70112, United States
| | - Jing He
- Department of Biochemistry
and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana 70112, United States
| | - William C. Wimley
- Department of Biochemistry
and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana 70112, United States
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106
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Ravensdale J, Wong Z, O'Brien F, Gregg K. Efficacy of Antibacterial Peptides Against Peptide-Resistant MRSA Is Restored by Permeabilization of Bacteria Membranes. Front Microbiol 2016; 7:1745. [PMID: 27877159 PMCID: PMC5099250 DOI: 10.3389/fmicb.2016.01745] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 10/19/2016] [Indexed: 11/13/2022] Open
Abstract
Clinical application of antimicrobial peptides (AMPs), as with conventional antibiotics, may be compromised by the development of bacterial resistance. This study investigated AMP resistance in methicillin resistant Staphylococcus aureus, including aspects related to the resilience of the resistant bacteria toward the peptides, the stability of resistance when selection pressures are removed, and whether resistance can be overcome by using the peptides with other membrane-permeabilising agents. Genotypically variant strains of S. aureus became equally resistant to the antibacterial peptides melittin and bac8c when grown in sub-lethal concentrations. Subculture of a melittin-resistant strain without melittin for 8 days lowered the minimal lethal concentration of the peptide from 170 μg ml-1 to 30 μg ml-1. Growth for 24 h in 12 μg ml-1 melittin restored the MLC to 100 μg ml-1. Flow cytometry analysis of cationic fluorophore binding to melittin-naïve and melittin-resistant bacteria revealed that resistance coincided with decreased binding of cationic molecules, suggesting a reduction in nett negative charge on the membrane. Melittin was haemolytic at low concentrations but the truncated analog of melittin, mel12-26, was confirmed to lack haemolytic activity. Although a previous report found that mel12-26 retained full bactericidal activity, we found it to lack significant activity when added to culture medium. However, electroporation in the presence of 50 μg ml-1 of mel12-26, killed 99.3% of the bacteria. Similarly, using a low concentration of the non-ionic detergent Triton X-100 to permeabilize bacteria to mel12-26 markedly increased its bactericidal activity. The observation that bactericidal activity of the non-membranolytic peptide mel12-26 was enhanced when the bacterial membrane was permeablized by detergents or electroporation, suggests that its principal mechanism in reducing bacterial survival may be through interaction with intracellular organelles or processes. Additionally, our results showed that the haemolytic peptide bac8c, had increased antibacterial activity at non-haemolytic concentrations when used with membrane-permeabilizing surfactants.
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Affiliation(s)
- Joshua Ravensdale
- School of Biomedical Science, Faculty of Health and Curtin Health Innovation Research Institute, Curtin University, Bentley WA, Australia
| | - Zachary Wong
- School of Biomedical Science, Faculty of Health and Curtin Health Innovation Research Institute, Curtin University, Bentley WA, Australia
| | - Frances O'Brien
- School of Biomedical Science, Faculty of Health and Curtin Health Innovation Research Institute, Curtin University, BentleyWA, Australia; Australian Collaborative Centre for Enterococcal and Staphylococcal Species (ACCESS) Typing and Research, Curtin University and PathWest Microbiology, Royal Perth Hospital, PerthWA, Australia
| | - Keith Gregg
- School of Biomedical Science, Faculty of Health and Curtin Health Innovation Research Institute, Curtin University, Bentley WA, Australia
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107
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AmyI-1–18, a cationic α-helical antimicrobial octadecapeptide derived from α-amylase in rice, inhibits the translation and folding processes in a protein synthesis system. J Biosci Bioeng 2016; 122:385-92. [DOI: 10.1016/j.jbiosc.2016.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/07/2016] [Accepted: 03/08/2016] [Indexed: 01/10/2023]
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108
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Xiao D, Hu JJ, Zhu JY, Wang SB, Zhuo RX, Zhang XZ. A redox-responsive mesoporous silica nanoparticle with a therapeutic peptide shell for tumor targeting synergistic therapy. NANOSCALE 2016; 8:16702-16709. [PMID: 27714082 DOI: 10.1039/c6nr04784j] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In this study, we report a novel redox-responsive mesoporous silica nanoparticle (MSN)-based nanocarrier, capping with a therapeutic peptide ((RGDWWW)2KC) containing a RGD target motif, for tumor targeting synergistic therapy, which is designated as TTSTMSN. The MSN was decorated with a tumor-targeting therapeutic peptide as a potential gatekeeper. The two branched peptides containing rich tryptophans allowed the pores to be blocked via π-π stacking and hydrophobic interactions. Once the drug loaded nanoparticles were taken up by the cancer cells through integrin-mediated endocytosis, the therapeutic peptide capping shells on the surface of MSNs were released, inducing the loaded drug to diffuse into the cytoplasm after breaking of the disulfide bonds, triggered by the high concentration of glutathione (GSH) in cancer cells. At the same time, the falling therapeutic rich tryptophans in the branched chains interacted with DNA due to the indole rings, leading to disturbance of the DNA structure through the strong π interactions and causing cell apoptosis. There is no such report on capping of drug loaded porous silica with a therapeutic peptide shell, co-delivering an anticancer drug and therapeutic agent for tumor targeting synergistic therapy, which will have great potential in developing multifunctional nanocarriers based on therapeutic peptides for synergistic treatment.
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Affiliation(s)
- Dong Xiao
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan 430072, P. R. China.
| | - Jing-Jing Hu
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan 430072, P. R. China.
| | - Jing-Yi Zhu
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan 430072, P. R. China.
| | - Shi-Bo Wang
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan 430072, P. R. China.
| | - Ren-Xi Zhuo
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan 430072, P. R. China.
| | - Xian-Zheng Zhang
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan 430072, P. R. China.
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109
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Pellino-1 derived cationic antimicrobial prawn peptide: Bactericidal activity, toxicity and mode of action. Mol Immunol 2016; 78:171-182. [PMID: 27648859 DOI: 10.1016/j.molimm.2016.09.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/09/2016] [Accepted: 09/11/2016] [Indexed: 02/07/2023]
Abstract
The antimicrobial peptides (AMPs) are multifunctional molecules which represent significant roles in the innate immune system. These molecules have been well known for decades because of their role as natural antibiotics in both invertebrates and vertebrates. The development of multiple drug resistance against conventional antibiotics brought a greater focus on AMPs in recent years. The cationic peptides, in particular, proven as host defense peptides and are considered as effectors of innate immunity. Among the various innate immune molecules, functions of pellino-1 (Peli-1) have been recently studied for its remarkable role in specific immune functions. In our study, we have identified Peli-1 from the cDNA library of freshwater prawn Macrobrachium rosenbergii (Mr) and analyzed its features using various in-silico methods. Real time PCR analysis showed an induced expression of MrPeli-1 during white spot syndrome virus (WSSV), bacteria (Vibrio harveyi) and lipopolysaccharide (LPS) from Escherichia coli challenge. Also, a cationic AMP named MrDN was derived from MrPeli-1 protein sequence and its activity was confirmed against various pathogenic bacteria. The mode of action of MrDN was determined to be its membrane permeabilization ability against Bacillus cereus ATCC 2106 as well as its DNA binding ability. Further, scanning electron microscopic (SEM) images showed the membrane disruption and leakage of cellular components of B. cereus cells induced by MrDN. The toxicity of MrDN against normal cells (HEK293 cells) was demonstrated by MTT and hemolysis assays. Overall, the results demonstrated the innate immune function of MrPeli-1 with a potential cationic AMP in prawn.
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110
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Pushpanathan M, Pooja S, Gunasekaran P, Rajendhran J. Critical Evaluation and Compilation of Physicochemical Determinants and Membrane Interactions of MMGP1 Antifungal Peptide. Mol Pharm 2016; 13:1656-67. [PMID: 26987762 DOI: 10.1021/acs.molpharmaceut.6b00086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A growing issue of pathogen resistance to antibiotics has fostered the development of innovative approaches for novel drug development. Here, we report the physicochemical and biological properties of an antifungal peptide, MMGP1, based on computational analysis. Computation of physicochemical properties has revealed that the natural biological activities of MMGP1 are coordinated by its intrinsic properties such as net positive charge (+5.04), amphipathicity, high hydrophobicity, low hydrophobic moment, and higher isoelectric point (11.915). Prediction of aggregation hot spots in MMGP1 had revealed the presence of potentially aggregation-prone segments that can nucleate in vivo aggregation (on the membrane), whereas no aggregating regions were predicted for in vitro aggregation (in solutions) of MMGP1. This ability of MMGP1 to form oligomeric aggregates on membrane further substantiates its direct-cell penetrating potency. Monte Carlo simulation of the interactions of MMGP1 in the aqueous phase and different membrane environments revealed that increasing the proportion of acidic lipids on membrane had led to increase in the peptide helicity. Furthermore, the peptide adopts energetically favorable transmembrane configuration, by inserting peptide loop and helix termini into the membrane containing >60% of anionic lipids. The charged lipid-based insertion of MMGP1 into membrane might be responsible for the selectivity of peptide toward fungal cells. Additionally, MMGP1 possessed DNA-binding property. Computational docking has identified DNA-binding residues (TRP3, SER4, MET7, ARG8, PHE10, ALA11, GLY20, THR21, ARG22, MET23, TRP34, and LYS36) in MMGP1 crucial for its DNA-binding property. Furthermore, computational mutation analysis revealed that aromatic amino acids are crucial for in vivo aggregation, membrane insertion, and DNA-binding property of MMGP1. These data provide new insight into the molecular determinants of MMGP1 antifungal activity and also serves as the template for the design of novel peptide antibiotics.
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Affiliation(s)
- Muthuirulan Pushpanathan
- Laboratory of Gene Regulation and Development, National Institutes of Child Health and Human Development, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Sharma Pooja
- Department of Animal and Avian Sciences, University of Maryland , College Park, Maryland 20740, United States
| | - Paramasamy Gunasekaran
- Department of Genetics, School of Biological Sciences, Madurai Kamaraj University , Madurai 625 021, India
| | - Jeyaprakash Rajendhran
- Department of Genetics, School of Biological Sciences, Madurai Kamaraj University , Madurai 625 021, India
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111
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Zhang W, Markiewicz BN, Doerksen RS, Smith AB, Gai F. C≡N stretching vibration of 5-cyanotryptophan as an infrared probe of protein local environment: what determines its frequency? Phys Chem Chem Phys 2016; 18:7027-34. [PMID: 26343769 PMCID: PMC4775302 DOI: 10.1039/c5cp04413h] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Recently it has been suggested that the C≡N stretching vibration of a tryptophan analog, 5-cyanotryptophan, could be used as an infrared probe of the local environment, especially the hydration status, of tryptophan residues in proteins. However, the factors that influence the frequency of this vibrational mode are not understood. To determine these factors, herein we carried out linear and nonlinear infrared measurements on the C≡N stretching vibration of the sidechain of 5-cyanotryptophan, 3-methyl-5-cyanoindole, in a series of protic and aprotic solvents. We found that while the C≡N stretching frequencies obtained in these solvents do not correlate well with any individual Kamlet-Taft solvent parameter, i.e., π* (polarizability), β (hydrogen bond accepting ability), and α (hydrogen bond donating ability), they do however, collapse on a straight line when plotted against σ = π* + β - α. This linear relationship provides a firm indication that both specific interactions, i.e., hydrogen-bonding interactions with the C≡N (through α) and indole N-H (through β) groups, and non-specific interactions with the molecule (through π*) work together to determine the C≡N stretching frequency, thus laying a quantitative framework for applying 5-cyanotryptophan to investigate the microscopic environment of proteins in a site-specific manner. Furthermore, two-dimensional and pump-probe infrared measurements revealed that a significant portion (∼31%) of the ground state bleach signal has a decay time constant of ∼12.3 ps, due to an additional vibrational relaxation channel, making it possible to use 5-cyanotryptophan to probe dynamics occurring on a timescale on the order of tens of picoseconds.
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Affiliation(s)
- Wenkai Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA. and The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Rosalie S Doerksen
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA. and The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA
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112
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Shi W, Li C, Li M, Zong X, Han D, Chen Y. Antimicrobial peptide melittin against Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen in rice. Appl Microbiol Biotechnol 2016; 100:5059-67. [PMID: 26948237 PMCID: PMC4866983 DOI: 10.1007/s00253-016-7400-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/12/2016] [Accepted: 02/16/2016] [Indexed: 11/28/2022]
Abstract
Xanthomonas oryzae pv. oryzae is a destructive bacterial disease of rice, and the development of an environmentally safe bactericide is urgently needed. Antimicrobial peptides, as antibacterial sources, may play important roles in bactericide development. In the present study, we found that the antimicrobial peptide melittin had the desired antibacterial activity against X. oryzae pv. oryzae. The antibacterial mechanism was investigated by examining its effects on cell membranes, energy metabolism, and nucleic acid, and protein synthesis. The antibacterial effects arose from its ability to interact with the bacterial cell wall and disrupt the cytoplasmic membrane by making holes and channels, resulting in the leakage of the cytoplasmic content. Additionally, melittin is able to permeabilize bacterial membranes and reach the cytoplasm, indicating that there are multiple mechanisms of antimicrobial action. DNA/RNA binding assay suggests that melittin may inhibit macromolecular biosynthesis by binding intracellular targets, such as DNA or RNA, and that those two modes eventually lead to bacterial cell death. Melittin can inhibit X. oryzae pv. oryzae from spreading, alleviating the disease symptoms, which indicated that melittin may have potential applications in plant protection.
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Affiliation(s)
- Wei Shi
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing, 210023, China
| | - Caiyun Li
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing, 210023, China
| | - Man Li
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing, 210023, China
| | - Xicui Zong
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing, 210023, China
| | - Dongju Han
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing, 210023, China
| | - Yuqing Chen
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing, 210023, China.
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113
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Ho YH, Shah P, Chen YW, Chen CS. Systematic Analysis of Intracellular-targeting Antimicrobial Peptides, Bactenecin 7, Hybrid of Pleurocidin and Dermaseptin, Proline-Arginine-rich Peptide, and Lactoferricin B, by Using Escherichia coli Proteome Microarrays. Mol Cell Proteomics 2016; 15:1837-47. [PMID: 26902206 DOI: 10.1074/mcp.m115.054999] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Indexed: 01/12/2023] Open
Abstract
Antimicrobial peptides (AMPs) act either through membrane lysis or by attacking intracellular targets. Intracellular targeting AMPs are a resource for antimicrobial agent development. Several AMPs have been identified as intracellular targeting peptides; however, the intracellular targets of many of these peptides remain unknown. In the present study, we used an Escherichia coli proteome microarray to systematically identify the protein targets of three intracellular targeting AMPs: bactenecin 7 (Bac7), a hybrid of pleurocidin and dermaseptin (P-Der), and proline-arginine-rich peptide (PR-39). In addition, we also included the data of lactoferricin B (LfcinB) from our previous study for a more comprehensive analysis. We analyzed the unique protein hits of each AMP in the Kyoto Encyclopedia of Genes and Genomes. The results indicated that Bac7 targets purine metabolism and histidine kinase, LfcinB attacks the transcription-related activities and several cellular carbohydrate biosynthetic processes, P-Der affects several catabolic processes of small molecules, and PR-39 preferentially recognizes proteins involved in RNA- and folate-metabolism-related cellular processes. Moreover, both Bac7 and LfcinB target purine metabolism, whereas LfcinB and PR-39 target lipopolysaccharide biosynthesis. This suggested that LfcinB and Bac7 as well as LfcinB and PR-39 have a synergistic effect on antimicrobial activity, which was validated through antimicrobial assays. Furthermore, common hits of all four AMPs indicated that all of them target arginine decarboxylase, which is a crucial enzyme for Escherichia coli survival in extremely acidic environments. Thus, these AMPs may display greater inhibition to bacterial growth in extremely acidic environments. We have also confirmed this finding in bacterial growth inhibition assays. In conclusion, this comprehensive identification and systematic analysis of intracellular targeting AMPs reveals crucial insights into the intracellular mechanisms of the action of AMPs.
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Affiliation(s)
- Yu-Hsuan Ho
- From the ‡Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jhongli 32001, Taiwan; §Department of Biomedical Science and Engineering, National Central University, Jhongli 32001, Taiwan
| | - Pramod Shah
- From the ‡Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jhongli 32001, Taiwan; §Department of Biomedical Science and Engineering, National Central University, Jhongli 32001, Taiwan
| | - Yi-Wen Chen
- From the ‡Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jhongli 32001, Taiwan; §Department of Biomedical Science and Engineering, National Central University, Jhongli 32001, Taiwan
| | - Chien-Sheng Chen
- From the ‡Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jhongli 32001, Taiwan; §Department of Biomedical Science and Engineering, National Central University, Jhongli 32001, Taiwan
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114
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Shah P, Hsiao FSH, Ho YH, Chen CS. The proteome targets of intracellular targeting antimicrobial peptides. Proteomics 2016; 16:1225-37. [PMID: 26648572 DOI: 10.1002/pmic.201500380] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 10/30/2015] [Accepted: 12/03/2015] [Indexed: 01/28/2023]
Abstract
Antimicrobial peptides have been considered well-deserving candidates to fight the battle against microorganisms due to their broad-spectrum antimicrobial activities. Several studies have suggested that membrane disruption is the basic mechanism of AMPs that leads to killing or inhibiting microorganisms. Also, AMPs have been reported to interact with macromolecules inside the microbial cells such as nucleic acids (DNA/RNA), protein synthesis, essential enzymes, membrane septum formation and cell wall synthesis. Proteins are associated with many intracellular mechanisms of cells, thus protein targets may be specifically involved in mechanisms of action of AMPs. AMPs like pyrrhocoricin, drosocin, apidecin and Bac 7 are documented to have protein targets, DnaK and GroEL. Moreover, the intracellular targeting AMPs are reported to influence more than one protein targets inside the cell, suggesting for the multiple modes of actions. This complex mechanism of intracellular targeting AMPs makes them more difficult for the development of resistance. Herein, we have summarized the current status of AMPs in terms of their mode of actions, entry to cytoplasm and inhibition of macromolecules. To reveal the mechanism of action, we have focused on AMPs with intracellular protein targets. We have also included the use of high-throughput proteome microarray to determine the unidentified AMP protein targets in this review.
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Affiliation(s)
- Pramod Shah
- Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jhongli, Taiwan.,Department of Biomedical Science and Engineering, National Central University, Jhongli, Taiwan
| | - Felix Shih-Hsiang Hsiao
- Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jhongli, Taiwan.,Department of Biomedical Science and Engineering, National Central University, Jhongli, Taiwan
| | - Yu-Hsuan Ho
- Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jhongli, Taiwan.,Department of Biomedical Science and Engineering, National Central University, Jhongli, Taiwan
| | - Chien-Sheng Chen
- Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jhongli, Taiwan.,Department of Biomedical Science and Engineering, National Central University, Jhongli, Taiwan
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115
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Nguyen LT, Chau JK, Zaat SAJ, Vogel HJ. Cyclic Tritrpticin Analogs with Distinct Biological Activities. Probiotics Antimicrob Proteins 2016; 3:132-43. [PMID: 26781579 DOI: 10.1007/s12602-011-9067-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Tritrpticin is a Trp-, Arg-, and Pro-rich cathelicidin peptide with promising antimicrobial activity. Cyclic analogs of tritrpticin were designed using two different approaches: circularization of the backbone by a head-to-tail peptide bond (TritrpCyc) or disulfide bridging between two Cys residues introduced at the termini of the peptide (TritrpDisu). Compared to the parent peptide, TritrpCyc has greatly improved therapeutic potential, showing stronger bactericidal activities and diminished hemolytic activity. Unexpectedly, the opposite effect was observed for TritrpDisu, which has lost its antimicrobial activity and is very hemolytic. In a membrane mimetic environment, NMR spectra show that TritrpDisu adopts an amphipathic turn-turn structure similar to linear tritrpticin. The structure of membrane-bound TritrpCyc has some similarity to that of TritrpDisu; however, the lipid interactions were not sufficient to restrain the structure of the former peptide in a single well-defined conformation. To help explain the distinct biological properties of the analogs, experiments investigating alternative antimicrobial targets were pursued: the membrane bilayer, lipopolysaccharides, and DNA. Although the hemolytic activity of TritrpDisu can be explained by the peptide's ability to induce higher leakage from the model mammalian membranes, TritrpCyc and TritrpDisu show no significant differences in these functional assays. Overall, our studies show that TritrpCyc holds great promise as a candidate for further development toward antimicrobial therapy.
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Affiliation(s)
- Leonard T Nguyen
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Alberta, Canada
| | - Johnny K Chau
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Alberta, Canada
| | - Sebastian A J Zaat
- Department of Medical Microbiology, Centre for Infection and Immunity Amsterdam, Academic Medical Center, Amsterdam, The Netherlands
| | - Hans J Vogel
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Alberta, Canada.
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116
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Libardo MDJ, Gorbatyuk VY, Angeles-Boza AM. Central Role of the Copper-Binding Motif in the Complex Mechanism of Action of Ixosin: Enhancing Oxidative Damage and Promoting Synergy with Ixosin B. ACS Infect Dis 2016; 2:71-81. [PMID: 27622949 DOI: 10.1021/acsinfecdis.5b00140] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ticks transmit multiple pathogens to different hosts without compromising their health. Their ability to evade microbial infections is largely a result of their effective innate immune response including various antimicrobial peptides. Therefore, a deep understanding of how ticks (and other arthropod vectors) control microbial loads could lead to the design of broad-spectrum antimicrobial agents. In this paper we study the role of the amino-terminal copper and nickel (ATCUN)-binding sequence in the peptide ixosin, isolated from the salivary glands of the hard tick Ixodes sinensis. Our results indicate that the ATCUN motif is not essential to the potency of ixosin, but is indispensable to its oxidative mechanism of action. Specifically, the ATCUN motif promotes dioxygen- and copper-dependent lipid (per)oxidation of bacterial membranes in a temporal fashion coinciding with the onset of bacterial death. Microscopy and studies on model membranes indicate that the oxidized phospholipids are utilized as potential targets of ixosin B (another tick salivary gland peptide) involving its delocalization to the bacterial membrane, thus resulting in a synergistic effect. Our proposed mechanism of action highlights the centrality of the ATCUN motif to ixosin's mechanism of action and demonstrates a novel way in which (tick) antimicrobial peptides (AMPs) utilize metal ions in its activity. This study suggests that ticks employ a variety of effectors to generate an amplified immune response, possibly justifying its vector competence.
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Affiliation(s)
- M. Daben J. Libardo
- Department of Chemistry, University of Connecticut, Unit 3060, 55 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Vitaliy Y. Gorbatyuk
- Department of Chemistry, University of Connecticut, Unit 3060, 55 North Eagleville Road, Storrs, Connecticut 06269, United States
- Biotechnology and Bioservices Center, University of Connecticut, Unit 3149, 91 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Alfredo M. Angeles-Boza
- Department of Chemistry, University of Connecticut, Unit 3060, 55 North Eagleville Road, Storrs, Connecticut 06269, United States
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117
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Diversity, Antimicrobial Action and Structure-Activity Relationship of Buffalo Cathelicidins. PLoS One 2015; 10:e0144741. [PMID: 26675301 PMCID: PMC4684500 DOI: 10.1371/journal.pone.0144741] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/22/2015] [Indexed: 02/07/2023] Open
Abstract
Cathelicidins are an ancient class of antimicrobial peptides (AMPs) with broad spectrum bactericidal activities. In this study, we investigated the diversity and biological activity of cathelicidins of buffalo, a species known for its disease resistance. A series of new homologs of cathelicidin4 (CATHL4), which were structurally diverse in their antimicrobial domain, was identified in buffalo. AMPs of newly identified buffalo CATHL4s (buCATHL4s) displayed potent antimicrobial activity against selected Gram positive (G+) and Gram negative (G-) bacteria. These peptides were prompt to disrupt the membrane integrity of bacteria and induced specific changes such as blebing, budding, and pore like structure formation on bacterial membrane. The peptides assumed different secondary structure conformations in aqueous and membrane-mimicking environments. Simulation studies suggested that the amphipathic design of buCATHL4 was crucial for water permeation following membrane disruption. A great diversity, broad-spectrum antimicrobial action, and ability to induce an inflammatory response indicated the pleiotropic role of cathelicidins in innate immunity of buffalo. This study suggests short buffalo cathelicidin peptides with potent bactericidal properties and low cytotoxicity have potential translational applications for the development of novel antibiotics and antimicrobial peptidomimetics.
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118
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Taniguchi M, Ochiai A, Kondo H, Fukuda S, Ishiyama Y, Saitoh E, Kato T, Tanaka T. Pyrrhocoricin, a proline-rich antimicrobial peptide derived from insect, inhibits the translation process in the cell-free Escherichia coli protein synthesis system. J Biosci Bioeng 2015; 121:591-8. [PMID: 26472128 DOI: 10.1016/j.jbiosc.2015.09.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 09/07/2015] [Accepted: 09/07/2015] [Indexed: 01/28/2023]
Abstract
Previous studies have shown that pyrrhocoricin, a proline-rich antimicrobial peptide (PrAMP), killed sensitive species in a dose-dependent manner by specifically binding to DnaK. Here, on the basis of the finding that DnaK-deficient Escherichia coli strains are susceptible to PrAMPs, we used pyrrhocoricin to investigate internal targets other than DnaK. Using conventional antibiotics (bleomycin, streptomycin, and fosfomycin) that have known modes of action, first, we validated the availability of an assay using a cell-free rapid translation system (RTS), which is an in vitro protein synthesis system based on E. coli lysate, for evaluating inhibition of protein synthesis. We found that, similarly to bleomycin and streptomycin, pyrrhocoricin inhibited GFP synthesis in RTS in a concentration-dependent manner. In addition, blockage of transcription and translation steps in RTS was individually estimated using RT-PCR after gene expression to determine mRNA products and using sodium dodecyl sulfate-polyacrylamide gel electrophoresis to determine the amounts of GFP expressed from purified mRNA, respectively. The results demonstrated that this inhibition of GFP synthesis by pyrrhocoricin did not occur at the transcription step but rather at the translation step, in a manner similar to that of GFP synthesis by streptomycin, an inhibitor of the translation step by causing misreading of tRNA. These results suggest that RTS is a powerful assay system for determining if antimicrobial peptides inhibit protein synthesis and its transcription and/or translation steps. This is the first study to have shown that pyrrhocoricin inhibited protein synthesis by specifically repressing the translation step.
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Affiliation(s)
- Masayuki Taniguchi
- Department of Materials Science and Technology, Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan; Center for Transdisciplinary Research, Niigata University, Niigata 950-2181, Japan.
| | - Akihito Ochiai
- Department of Materials Science and Technology, Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
| | - Hiroshi Kondo
- Department of Materials Science and Technology, Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
| | - Shun Fukuda
- Department of Materials Science and Technology, Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
| | - Yohei Ishiyama
- Center for Fostering Innovative Leadership, Niigata University, Niigata 950-2181, Japan
| | - Eiichi Saitoh
- Graduate School of Technology, Niigata Institute of Technology, Niigata 945-1195, Japan
| | - Tetsuo Kato
- Department of Chemistry, Tokyo Dental College, Tokyo 101-0062, Japan
| | - Takaaki Tanaka
- Department of Materials Science and Technology, Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
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119
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Kumaresan V, Bhatt P, Ganesh MR, Harikrishnan R, Arasu M, Al-Dhabi NA, Pasupuleti M, Marimuthu K, Arockiaraj J. A novel antimicrobial peptide derived from fish goose type lysozyme disrupts the membrane of Salmonella enterica. Mol Immunol 2015; 68:421-33. [PMID: 26477736 DOI: 10.1016/j.molimm.2015.10.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 09/30/2015] [Accepted: 10/02/2015] [Indexed: 12/21/2022]
Abstract
In aquaculture, accumulation of antibiotics resulted in development of resistance among bacterial pathogens. Consequently, it became mandatory to find alternative to synthetic antibiotics. Antimicrobial peptides (AMPs) which are described as evolutionary ancient weapons have been considered as promising alternates in recent years. In this study, a novel antimicrobial peptide had been derived from goose type lysozyme (LyzG) which was identified from the cDNA library of freshwater fish Channa striatus (Cs). The identified lysozyme cDNA contains 585 nucleotides which encodes a protein of 194 amino acids. CsLyzG was closely related to Siniperca chuatsi with 92.8% homology. The depicted protein sequence contained a GEWL domain with conserved GLMQ motif, 7 active residues and 2 catalytic residues. Gene expression analysis revealed that CsLyzG was distributed in major immune organs with highest expression in head kidney. Results of temporal expression analysis after bacterial (Aeromonas hydrophila) and fungal (Aphanomyces invadans) challenges indicated a stimulant-dependent expression pattern of CsLyzG. Two antimicrobial peptides IK12 and TS10 were identified from CsLyzG and synthesized. Antibiogram showed that IK12 was active against Salmonella enterica, a major multi-drug resistant (MDR) bacterial pathogen which produces beta lactamase. The IK12 induced loss of cell viability in the bacterial pathogen. Flow cytometry assay revealed that IK12 disrupt the membrane of S. enterica which is confirmed by scanning electron microscope (SEM) analysis that reveals blebs around the bacterial cell membrane. Conclusively, CsLyzG is a potential innate immune component and the identified antimicrobial peptide has great caliber to be used as an ecofriendly antibacterial substance in aquaculture.
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Affiliation(s)
- Venkatesh Kumaresan
- Division of Fisheries Biotechnology & Molecular Biology, Department of Biotechnology, Faculty of Science and Humanities, SRM University, Kattankulathur, 603 203 Chennai, Tamil Nadu, India
| | - Prasanth Bhatt
- Division of Fisheries Biotechnology & Molecular Biology, Department of Biotechnology, Faculty of Science and Humanities, SRM University, Kattankulathur, 603 203 Chennai, Tamil Nadu, India
| | - Munuswamy-Ramanujam Ganesh
- Interdisciplinary Institute of Indian System of Medicine, SRM University, Kattankulathur, 603 203 Chennai, Tamil Nadu, India
| | - Ramasamy Harikrishnan
- Department of Zoology, Pachaiyappa's College for Men, Kanchipuram 631 501 Tamil Nadu, India
| | - MariadhasValan Arasu
- Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies, College of Science, King Saud University, P. O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Naif Abdullah Al-Dhabi
- Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies, College of Science, King Saud University, P. O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Mukesh Pasupuleti
- Lab PCN 206, Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226 031 Uttar Pradesh, India
| | - Kasi Marimuthu
- Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Semeling Bedong, 08100 Bedong, Kedah, Malaysia
| | - Jesu Arockiaraj
- Division of Fisheries Biotechnology & Molecular Biology, Department of Biotechnology, Faculty of Science and Humanities, SRM University, Kattankulathur, 603 203 Chennai, Tamil Nadu, India.
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120
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Tsai CW, Hu WW, Liu CI, Ruaan RC, Tsai BC, Jin SLC, Chang Y, Chen WY. The consideration of indolicidin modification to balance its hemocompatibility and delivery efficiency. Int J Pharm 2015; 494:498-505. [DOI: 10.1016/j.ijpharm.2015.08.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 07/24/2015] [Accepted: 08/13/2015] [Indexed: 01/21/2023]
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121
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Taute H, Bester MJ, Neitz AWH, Gaspar ARM. Investigation into the mechanism of action of the antimicrobial peptides Os and Os-C derived from a tick defensin. Peptides 2015. [PMID: 26215047 DOI: 10.1016/j.peptides.2015.07.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Os and Os-C are two novel antimicrobial peptides, derived from a tick defensin, which have been shown to have a larger range of antimicrobial activity than the parent peptide, OsDef2. The aim of this study was to determine whether the peptides Os and Os-C are mainly membrane acting, or if these peptides have possible additional intracellular targets in Escherichia coli and Bacillus subtilis. Transmission electron microscopy revealed that both peptides adversely affected intracellular structure of both bacteria causing different degrees of granulation of the intracellular contents. At the minimum bactericidal concentrations, permeabilization as determined with the SYTOX green assay seemed not to be the principle mode of killing when compared to melittin. However, fluorescent triple staining indicated that the peptides caused permeabilization of stationary phase bacteria and TEM indicated membrane effects. Studies using fluorescently labeled peptides revealed that the membrane penetrating activity of Os and Os-C was similar to buforin II. Os-C was found to associate with the septa of B. subtilis. Plasmid binding studies showed that Os and Os-C binds E. coli plasmid DNA at a similar charge ratio as melittin. These studies suggest membrane activity for Os and Os-C with possible intracellular targets such as DNA. The differences in permeabilization at lower concentrations and binding to DNA between Os and Os-C, suggest that the two peptides have dissimilar modes of action.
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Affiliation(s)
- Helena Taute
- Department of Anatomy, Faculty of Health Sciences, University of Pretoria, 0002, South Africa.
| | - Megan J Bester
- Department of Anatomy, Faculty of Health Sciences, University of Pretoria, 0002, South Africa
| | - Albert W H Neitz
- Department of Biochemistry, Faculty of Natural Sciences, University of Pretoria, 0002, South Africa
| | - Anabella R M Gaspar
- Department of Biochemistry, Faculty of Natural Sciences, University of Pretoria, 0002, South Africa
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122
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Xi D, Wang X, Teng D, Mao R. Mechanism of action of the tri-hybrid antimicrobial peptide LHP7 from lactoferricin, HP and plectasin on Staphylococcus aureus. Biometals 2015; 27:957-68. [PMID: 25015218 DOI: 10.1007/s10534-014-9768-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 06/24/2014] [Indexed: 11/28/2022]
Abstract
The tri-hybrid peptide-LHP7 has the potent activity against Gram-positive and Gram-negative as well as fungi, but its mechanism of action has remained elusive. The effluences of LHP7 on the Staphylococcus aureus cell membrane and targets of intracellular action were investigated. LHP7 exhibited an inhibitory effect on the S. aureus growth, similar to those achieved by plectasin, vancomycin and gramicidin. The membrane integrity studies confirmed that LHP7 disrupted the cell membrane, indicating a membrane permeabilizing killing action. A marginal decline in the intensity fluorescence indicated no significant depolarization of the membrane potential following LHP7 treatment. Furthermore, electron microscopy showed that cell shrinkage, cell wall thickening, cellular content leakage, and cell disruption were observed in the cells treated with LHP7. A gel retardation assay showed that LHP7 bound to the genomic DNA of S. aureus or plasmid DNA at a mass ratio of 2.5–10 (peptide/DNA). Circular dichroism indicated that LHP7 inserted into the groove of DNA. The cell cycle analysis showed that after the treatment with LHP7 for 30 and 60 min, the proportion of cells in I-phase increased from 8.71 to 12.09 % and from 8.71 to 15.68 %, indicating that LHP7 induced arrest of cells in the I-phase. These results would conduce to elucidate its underlying antibacterial mechanism.
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123
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Peptides and Peptidomimetics for Antimicrobial Drug Design. Pharmaceuticals (Basel) 2015; 8:366-415. [PMID: 26184232 PMCID: PMC4588174 DOI: 10.3390/ph8030366] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/27/2015] [Accepted: 06/17/2015] [Indexed: 12/21/2022] Open
Abstract
The purpose of this paper is to introduce and highlight a few classes of traditional antimicrobial peptides with a focus on structure-activity relationship studies. After first dissecting the important physiochemical properties that influence the antimicrobial and toxic properties of antimicrobial peptides, the contributions of individual amino acids with respect to the peptides antibacterial properties are presented. A brief discussion of the mechanisms of action of different antimicrobials as well as the development of bacterial resistance towards antimicrobial peptides follows. Finally, current efforts on novel design strategies and peptidomimetics are introduced to illustrate the importance of antimicrobial peptide research in the development of future antibiotics.
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124
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Tian X, Sun F, Zhou XR, Luo SZ, Chen L. Role of peptide self-assembly in antimicrobial peptides. J Pept Sci 2015; 21:530-9. [DOI: 10.1002/psc.2788] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 05/05/2015] [Accepted: 05/05/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Xibo Tian
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology; Beijing University of Chemical Technology; Beijing 100029 China
| | - Fude Sun
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology; Beijing University of Chemical Technology; Beijing 100029 China
| | - Xi-Rui Zhou
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology; Beijing University of Chemical Technology; Beijing 100029 China
| | - Shi-Zhong Luo
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology; Beijing University of Chemical Technology; Beijing 100029 China
| | - Long Chen
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology; Beijing University of Chemical Technology; Beijing 100029 China
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125
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Molecular characterization of the liver-expressed antimicrobial peptide 2 (LEAP-2) in a teleost fish, Plecoglossus altivelis: Antimicrobial activity and molecular mechanism. Mol Immunol 2015; 65:406-15. [DOI: 10.1016/j.molimm.2015.02.022] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 02/16/2015] [Accepted: 02/19/2015] [Indexed: 02/01/2023]
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126
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An unprecedented alteration in mode of action of IsCT resulting its translocation into bacterial cytoplasm and inhibition of macromolecular syntheses. Sci Rep 2015; 5:9127. [PMID: 25773522 PMCID: PMC4360471 DOI: 10.1038/srep09127] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 01/30/2015] [Indexed: 01/12/2023] Open
Abstract
IsCT, a 13-residue, non-cell-selective antimicrobial peptide is comprised of mostly hydrophobic residues and lesser cationic residues. Assuming that placement of an additional positive charge in the non-polar face of IsCT could reduce its hydrophobic interaction, resulting in its reduction of cytotoxicity, an analog, I9K-IsCT was designed. Two more analogs, namely, E7K-IsCT and E7K,I9K-IsCT, were designed to investigate the impact of positive charges in the polar face as well as polar and non-polar faces at a time. These amino acid substitutions resulted in a significant enhancement of therapeutic potential of IsCT. IsCT and E7K-IsCT seem to target bacterial membrane for their anti-bacterial activity. However, I9K-IsCT and E7K,I9K-IsCT inhibited nucleic acid and protein syntheses in tested E. coli without perturbing its membrane. This was further supported by the observation that NBD-IsCT localized onto bacterial membrane while NBD-labeled I9K-IsCT and E7K,I9K-IsCT translocated into bacterial cytoplasm. Interestingly, IsCT and E7K-IsCT were significantly helical while I9K-IsCT and E7K,I9K-IsCT were mostly unstructured with no helix content in presence of mammalian and bacterial membrane-mimetic lipid vesicles. Altogether, the results identify two novel cell-selective analogs of IsCT with new prototype amino acid sequences that can translocate into bacterial cytoplasm without any helical structure and inhibit macromolecular syntheses.
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127
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Bactericidal efficiency and modes of action of the novel antimicrobial peptide T9W against Pseudomonas aeruginosa. Antimicrob Agents Chemother 2015; 59:3008-17. [PMID: 25753629 DOI: 10.1128/aac.04830-14] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/01/2015] [Indexed: 11/20/2022] Open
Abstract
The antipseudomonal efficiency and mechanism of action of a novel engineered antimicrobial peptide, T9W, were evaluated in this study. T9W displayed high activity, with a lethal concentration (LC) of 1 to 4 μM against Pseudomonas aeruginosa, including against ciprofloxacin-, gentamicin-, and ceftazidime-resistant strains, even in the presence of 50 to 300 mM NaCl, 1 to 5 mM Ca(2+), or 0.5 to 2 mM Mg(2+). The time-kill curve (TKC) analysis demonstrated concentration-dependent activity, with T9W achieving complete killing in less than 30 min at 1× LC and in less than 5 min at 4× LC. Combination TKC analyses additionally demonstrated a synergistic effect with ciprofloxacin and gentamicin. The selectivity of T9W was further supported by its ability to specifically eliminate P. aeruginosa in a coculture with macrophages without toxicity to the mammalian cells. The results from fluorescent measurement indicated that T9W bound to lipopolysaccharide (LPS) and induced P. aeruginosa membrane depolarization, and microscopic observations and flow cytometry further indicated that T9W targeted the P. aeruginosa cell membrane and disrupted cytoplasmic membrane integrity, thereby causing cellular content release leading to cell death. This study revealed the potential usefulness of T9W as a novel antimicrobial agent against P. aeruginosa.
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128
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Zhang X, Zhang Z, Xu X, Li Y, Li Y, Jian Y, Gu Z. Bioinspired Therapeutic Dendrimers as Efficient Peptide Drugs Based on Supramolecular Interactions for Tumor Inhibition. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201500683] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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129
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Zhang X, Zhang Z, Xu X, Li Y, Li Y, Jian Y, Gu Z. Bioinspired Therapeutic Dendrimers as Efficient Peptide Drugs Based on Supramolecular Interactions for Tumor Inhibition. Angew Chem Int Ed Engl 2015; 54:4289-94. [DOI: 10.1002/anie.201500683] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Indexed: 11/09/2022]
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130
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Vale N, Aguiar L, Gomes P. Antimicrobial peptides: a new class of antimalarial drugs? Front Pharmacol 2014; 5:275. [PMID: 25566072 PMCID: PMC4271771 DOI: 10.3389/fphar.2014.00275] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 11/26/2014] [Indexed: 12/12/2022] Open
Abstract
A range of antimicrobial peptides (AMP) exhibit activity on malaria parasites, Plasmodium spp., in their blood or mosquito stages, or both. These peptides include a diverse array of both natural and synthetic molecules varying greatly in size, charge, hydrophobicity, and secondary structure features. Along with an overview of relevant literature reports regarding AMP that display antiplasmodial activity, this review makes a few considerations about those molecules as a potential new class of antimalarial drugs.
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Affiliation(s)
- Nuno Vale
- Department of Chemistry and Biochemistry, Faculty of Sciences, Centro de Investigação em Química, University of Porto Porto, Portugal
| | - Luísa Aguiar
- Department of Chemistry and Biochemistry, Faculty of Sciences, Centro de Investigação em Química, University of Porto Porto, Portugal
| | - Paula Gomes
- Department of Chemistry and Biochemistry, Faculty of Sciences, Centro de Investigação em Química, University of Porto Porto, Portugal
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131
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Mardirossian M, Grzela R, Giglione C, Meinnel T, Gennaro R, Mergaert P, Scocchi M. The host antimicrobial peptide Bac71-35 binds to bacterial ribosomal proteins and inhibits protein synthesis. ACTA ACUST UNITED AC 2014; 21:1639-47. [PMID: 25455857 DOI: 10.1016/j.chembiol.2014.10.009] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 10/03/2014] [Accepted: 10/06/2014] [Indexed: 11/15/2022]
Abstract
Antimicrobial peptides (AMPs) are molecules from innate immunity with high potential as novel anti-infective agents. Most of them inactivate bacteria through pore formation or membrane barrier disruption, but others cross the membrane without damages and act inside the cells, affecting vital processes. However, little is known about their intracellular bacterial targets. Here we report that Bac71-35, a proline-rich AMP belonging to the cathelicidin family, can reach high concentrations (up to 340 μM) inside the E. coli cytoplasm. The peptide specifically and completely inhibits in vitro translation in the micromolar concentration range. Experiments of incorporation of radioactive precursors in macromolecules with E. coli cells confirmed that Bac71-35 affects specifically protein synthesis. Ribosome coprecipitation and crosslinking assays showed that the peptide interacts with ribosomes, binding to a limited subset of ribosomal proteins. Overall, these results indicate that the killing mechanism of Bac71-35 is based on a specific block of protein synthesis.
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Affiliation(s)
- Mario Mardirossian
- Department of Life Sciences, University of Trieste, Via Giorgieri 5, Trieste 34127, Italy
| | - Renata Grzela
- Institut des Sciences du Végétal UPR 2355 CNRS, 1 avenue de la Terrasse Bât. 23, 91198 Gif-sur-Yvette, France
| | - Carmela Giglione
- Institut des Sciences du Végétal UPR 2355 CNRS, 1 avenue de la Terrasse Bât. 23, 91198 Gif-sur-Yvette, France
| | - Thierry Meinnel
- Institut des Sciences du Végétal UPR 2355 CNRS, 1 avenue de la Terrasse Bât. 23, 91198 Gif-sur-Yvette, France
| | - Renato Gennaro
- Department of Life Sciences, University of Trieste, Via Giorgieri 5, Trieste 34127, Italy
| | - Peter Mergaert
- Institut des Sciences du Végétal UPR 2355 CNRS, 1 avenue de la Terrasse Bât. 23, 91198 Gif-sur-Yvette, France
| | - Marco Scocchi
- Department of Life Sciences, University of Trieste, Via Giorgieri 5, Trieste 34127, Italy.
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132
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Yi T, Huang Y, Chen Y. Production of an Antimicrobial Peptide AN5-1 inEscherichia coliand its Dual Mechanisms Against Bacteria. Chem Biol Drug Des 2014; 85:598-607. [DOI: 10.1111/cbdd.12449] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/23/2014] [Accepted: 09/30/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Tonghui Yi
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education; Jilin University; 2699 Qianjin Street Changchun Jilin 130012 China
- School of Life Sciences; Jilin University; Changchun Jilin 130012 China
| | - Yibing Huang
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education; Jilin University; 2699 Qianjin Street Changchun Jilin 130012 China
- School of Life Sciences; Jilin University; Changchun Jilin 130012 China
- National Engineering Laboratory for AIDS Vaccine; Jilin University; Changchun Jilin 130012 China
| | - Yuxin Chen
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education; Jilin University; 2699 Qianjin Street Changchun Jilin 130012 China
- School of Life Sciences; Jilin University; Changchun Jilin 130012 China
- National Engineering Laboratory for AIDS Vaccine; Jilin University; Changchun Jilin 130012 China
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133
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Antimicrobial activity of peptides derived from olive flounder lipopolysaccharide binding protein/bactericidal permeability-increasing protein (LBP/BPI). Mar Drugs 2014; 12:5240-57. [PMID: 25329706 PMCID: PMC4210897 DOI: 10.3390/md12105240] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/18/2014] [Accepted: 10/07/2014] [Indexed: 11/17/2022] Open
Abstract
We describe the antimicrobial function of peptides derived from the C-terminus of the olive flounder LBP BPI precursor protein. The investigated peptides, namely, ofLBP1N, ofLBP2A, ofLBP4N, ofLBP5A, and ofLBP6A, formed α-helical structures, showing significant antimicrobial activity against several Gram-negative bacteria, Gram-positive bacteria, and the yeast Candida albicans, but very limited hemolytic activities. The biological activities of these five analogs were evaluated against biomembranes or artificial membranes for the development of candidate therapeutic agents. Gel retardation studies revealed that peptides bound to DNA and inhibited migration on an agarose gel. In addition, we demonstrated that ofLBP6A inhibited polymerase chain reaction. These results suggested that the ofLBP-derived peptide bactericidal mechanism may be related to the interaction with intracellular components such as DNA or polymerase.
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134
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Wang KF, Nagarajan R, Camesano TA. Differentiating antimicrobial peptides interacting with lipid bilayer: Molecular signatures derived from quartz crystal microbalance with dissipation monitoring. Biophys Chem 2014; 196:53-67. [PMID: 25307196 DOI: 10.1016/j.bpc.2014.09.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 09/16/2014] [Accepted: 09/16/2014] [Indexed: 10/24/2022]
Abstract
Many antimicrobial peptides (AMPs) kill bacteria by disrupting the lipid bilayer structure of their inner membrane. However, there is only limited quantitative information in the literature to differentiate between AMPs of differing molecular properties, in terms of how they interact with the membrane. In this study, we have used quartz crystal microbalance with dissipation monitoring (QCM-D) to probe the interactions between a supported bilayer membrane of egg phosphatidylcholine (egg PC) and four structurally different AMPs: alamethicin, chrysophsin-3, indolicidin, and sheep myeloid antimicrobial peptide (SMAP-29). Multiple signatures from the QCM-D measurements were extracted, differentiating the AMPs, that provide information on peptide addition to and lipid removal from the membrane, the dynamics of peptide-membrane interactions and the rates at which the peptide actions are initiated. The mechanistic variations in peptide action were related to the fundamental structural properties of the peptides including the hydrophobicity, hydrophobic moment, and the probability of α-helical secondary structures.
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Affiliation(s)
- Kathleen F Wang
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA 01609, United States
| | - Ramanathan Nagarajan
- Molecular Sciences and Engineering Team, Natick Soldier Research, Development and Engineering Center, Natick, MA 01760, United States.
| | - Terri A Camesano
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA 01609, United States
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135
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Bandyopadhyay S, Junjie RL, Lim B, Sanjeev R, Xin WY, Yee CK, Hui Melodies SM, Yow N, Sivaraman J, Chatterjee C. Solution structures and model membrane interactions of Ctriporin, an anti-methicillin-resistantStaphylococcus aureusPeptide from Scorpion Venom. Biopolymers 2014; 101:1143-53. [DOI: 10.1002/bip.22519] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 05/14/2014] [Accepted: 06/06/2014] [Indexed: 02/04/2023]
Affiliation(s)
| | | | - Brendan Lim
- School of Applied Science; Republic Polytechnic Singapore
| | - R. Sanjeev
- School of Applied Science; Republic Polytechnic Singapore
| | - Woon Yong Xin
- School of Applied Science; Republic Polytechnic Singapore
| | - Chong Kok Yee
- School of Applied Science; Republic Polytechnic Singapore
| | | | - Nicole Yow
- School of Applied Science; Republic Polytechnic Singapore
| | - J. Sivaraman
- Department of Biological Sciences; National University of Singapore; Singapore
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136
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Schmidt NW, Deshayes S, Hawker S, Blacker A, Kasko AM, Wong GCL. Engineering persister-specific antibiotics with synergistic antimicrobial functions. ACS NANO 2014; 8:8786-93. [PMID: 25130648 PMCID: PMC4173747 DOI: 10.1021/nn502201a] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Most antibiotics target growth processes and are ineffective against persister bacterial cells, which tolerate antibiotics due to their reduced metabolic activity. These persisters act as a genetic reservoir for resistant mutants and constitute a root cause of antibiotic resistance, a worldwide problem in human health. We re-engineer antibiotics specifically for persisters using tobramycin, an aminoglycoside antibiotic that targets bacterial ribosomes but is ineffective against persisters with low metabolic and cellular transport activity. By giving tobramycin the ability to induce nanoscopic negative Gaussian membrane curvature via addition of 12 amino acids, we transform tobramycin itself into a transporter sequence. The resulting molecule spontaneously permeates membranes, retains the high antibiotic activity of aminoglycosides, kills E. coli and S. aureus persisters 4-6 logs better than tobramycin, but remains noncytotoxic to eukaryotes. These results suggest a promising paradigm to renovate traditional antibiotics.
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137
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Zhang M, Li MF, Sun L. NKLP27: a teleost NK-lysin peptide that modulates immune response, induces degradation of bacterial DNA, and inhibits bacterial and viral infection. PLoS One 2014; 9:e106543. [PMID: 25180858 PMCID: PMC4152322 DOI: 10.1371/journal.pone.0106543] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 08/06/2014] [Indexed: 12/30/2022] Open
Abstract
NK-lysin is an antimicrobial protein produced by cytotoxic T lymphocytes and natural killer cells. In this study, we examined the biological property of a peptide, NKLP27, derived from tongue sole (Cynoglossus semilaevis) NK-lysin. NKLP27 is composed of 27 amino acids and shares little sequence identity with known NK-lysin peptides. NKLP27 possesses bactericidal activity against both Gram-negative and Gram-positive bacteria including common aquaculture pathogens. The bactericidal activity of NKLP27 was dependent on the C-terminal five residues, deletion of which dramatically reduced the activity of NKLP27. During its interaction with the target bacterial cells, NKLP27 destroyed cell membrane integrity, penetrated into the cytoplasm, and induced degradation of genomic DNA. In vivo study showed that administration of tongue sole with NKLP27 before bacterial and viral infection significantly reduced pathogen dissemination and replication in tissues. Further study revealed that fish administered with NKLP27 exhibited significantly upregulated expression of the immune genes including those that are known to be involved in antibacterial and antiviral defense. These results indicate that NKLP27 is a novel antimicrobial against bacterial and viral pathogens, and that the observed effect of NKLP27 on bacterial DNA and host gene expression adds new insights to the action mechanism of fish antimicrobial peptides.
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Affiliation(s)
- Min Zhang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- College of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Mo-fei Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Graduate University of the Chinese Academy of Sciences, Beijing, China
| | - Li Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Collaborative Innovation Center of Deep Sea Biology, Zhejiang University, Hangzhou, China
- * E-mail:
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138
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Bandyopadhyay S, Ng BY, Chong C, Lim MZ, Gill SK, Lee KH, Sivaraman J, Chatterjee C. Micelle bound structure and DNA interaction of brevinin-2-related peptide, an antimicrobial peptide derived from frog skin. J Pept Sci 2014; 20:811-21. [DOI: 10.1002/psc.2673] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 05/23/2014] [Accepted: 06/13/2014] [Indexed: 11/11/2022]
Affiliation(s)
| | - Boon Yee Ng
- School of Applied Science; Republic Polytechnic; Singapore
| | | | - Ming Zhen Lim
- School of Applied Science; Republic Polytechnic; Singapore
| | | | - Ke Hui Lee
- School of Applied Science; Republic Polytechnic; Singapore
| | - J Sivaraman
- Department of Biological Sciences; National University of Singapore; Singapore
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139
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Ghosh A, Kar RK, Jana J, Saha A, Jana B, Krishnamoorthy J, Kumar D, Ghosh S, Chatterjee S, Bhunia A. Indolicidin targets duplex DNA: structural and mechanistic insight through a combination of spectroscopy and microscopy. ChemMedChem 2014; 9:2052-8. [PMID: 25044630 DOI: 10.1002/cmdc.201402215] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Indexed: 12/22/2022]
Abstract
Indolicidin (IR13), a 13-residue antimicrobial peptide from the cathelicidin family, is known to exhibit a broad spectrum of antimicrobial activity against various microorganisms. This peptide inhibits bacterial DNA synthesis resulting in cell filamentation. However, the precise mechanism remains unclear and requires further investigation. The central PWWP motif of IR13 provides a unique structural element that can wrap around, and thus stabilize, duplex B-type DNA structures. Replacements of the central Trp-Trp pair with Ala-Ala, His-His, or Phe-Phe residues in the PxxP motif significantly affects the ability of the peptide to stabilize duplex DNA. Results of microscopy studies in conjunction with spectroscopic data confirm that the DNA duplex is stabilized by IR13, thereby inhibiting DNA replication and transcription. In this study we provide high-resolution structural information on the interaction between indolicidin and DNA, which will be beneficial for the design of novel therapeutic antibiotics based on peptide scaffolds.
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Affiliation(s)
- Anirban Ghosh
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VII (M), Kolkata 700054 (India)
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140
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Joshi KB, Singh P. l-Proline induced self-assembly of indolicidin derived palindromic tripeptide. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.04.090] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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141
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Limoli DH, Rockel AB, Host KM, Jha A, Kopp BT, Hollis T, Wozniak DJ. Cationic antimicrobial peptides promote microbial mutagenesis and pathoadaptation in chronic infections. PLoS Pathog 2014; 10:e1004083. [PMID: 24763694 PMCID: PMC3999168 DOI: 10.1371/journal.ppat.1004083] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 03/09/2014] [Indexed: 12/30/2022] Open
Abstract
Acquisition of adaptive mutations is essential for microbial persistence during chronic infections. This is particularly evident during chronic Pseudomonas aeruginosa lung infections in cystic fibrosis (CF) patients. Thus far, mutagenesis has been attributed to the generation of reactive species by polymorphonucleocytes (PMN) and antibiotic treatment. However, our current studies of mutagenesis leading to P. aeruginosa mucoid conversion have revealed a potential new mutagen. Our findings confirmed the current view that reactive oxygen species can promote mucoidy in vitro, but revealed PMNs are proficient at inducing mucoid conversion in the absence of an oxidative burst. This led to the discovery that cationic antimicrobial peptides can be mutagenic and promote mucoidy. Of specific interest was the human cathelicidin LL-37, canonically known to disrupt bacterial membranes leading to cell death. An alternative role was revealed at sub-inhibitory concentrations, where LL-37 was found to induce mutations within the mucA gene encoding a negative regulator of mucoidy and to promote rifampin resistance in both P. aeruginosa and Escherichia coli. The mechanism of mutagenesis was found to be dependent upon sub-inhibitory concentrations of LL-37 entering the bacterial cytosol and binding to DNA. LL-37/DNA interactions then promote translesion DNA synthesis by the polymerase DinB, whose error-prone replication potentiates the mutations. A model of LL-37 bound to DNA was generated, which reveals amino termini α-helices of dimerized LL-37 bind the major groove of DNA, with numerous DNA contacts made by LL-37 basic residues. This demonstrates a mutagenic role for antimicrobials previously thought to be insusceptible to resistance by mutation, highlighting a need to further investigate their role in evolution and pathoadaptation in chronic infections. Antimicrobial peptides (AMPs) are produced by the mammalian immune system to fight invading pathogens. The best understood function of AMPs is to interact with the membranes of microbes, thereby disrupting and killing cells. However, the amount of AMP available during chronic bacterial infections may not be sufficient to kill pathogens (sub-inhibitory). In this study, we found that at sub-inhibitory levels, AMPs promote mutations in bacterial DNA, a function not previously attributed to them. In particular, we found that in the bacteria Pseudomonas aeruginosa, one AMP called LL-37 can promote mutations, which enable the bacteria to overproduce a protective sugar coating, a process called mucoid conversion. P. aeruginosa mucoid conversion is a major risk factor for those suffering from cystic fibrosis (CF), the most common lethal, heritable disease in the US. We found that LL-37 is able to produce these mutations by penetrating the bacterial cell and binding to the bacterial DNA. DNA binding disrupts normal DNA replication and allows mutations to occur. Furthermore, we observed LL-37 induced mutagenesis in processes apart from mucoid conversion, in both P. aeruginosa and E. coli. This suggests that AMP-induced mutagenesis may be important for a broad range of chronic diseases and pathogens.
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Affiliation(s)
- Dominique H. Limoli
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, United States of America
| | - Andrea B. Rockel
- Department of Natural Sciences, Mars Hill University, Mars Hill, North Carolina, United States of America
| | - Kurtis M. Host
- Medicine Administration, University of North Carolina Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Anuvrat Jha
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, United States of America
| | - Benjamin T. Kopp
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, United States of America
| | - Thomas Hollis
- Department of Biochemistry and Center for Structural Biology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Daniel J. Wozniak
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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142
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Lee MW, Chakraborty S, Schmidt NW, Murgai R, Gellman SH, Wong GCL. Two interdependent mechanisms of antimicrobial activity allow for efficient killing in nylon-3-based polymeric mimics of innate immunity peptides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2269-79. [PMID: 24743021 DOI: 10.1016/j.bbamem.2014.04.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 12/21/2022]
Abstract
Novel synthetic mimics of antimicrobial peptides have been developed to exhibit structural properties and antimicrobial activity similar to those of natural antimicrobial peptides (AMPs) of the innate immune system. These molecules have a number of potential advantages over conventional antibiotics, including reduced bacterial resistance, cost-effective preparation, and customizable designs. In this study, we investigate a family of nylon-3 polymer-based antimicrobials. By combining vesicle dye leakage, bacterial permeation, and bactericidal assays with small-angle X-ray scattering (SAXS), we find that these polymers are capable of two interdependent mechanisms of action: permeation of bacterial membranes and binding to intracellular targets such as DNA, with the latter necessarily dependent on the former. We systemically examine polymer-induced membrane deformation modes across a range of lipid compositions that mimic both bacteria and mammalian cell membranes. The results show that the polymers' ability to generate negative Gaussian curvature (NGC), a topological requirement for membrane permeation and cellular entry, in model Escherichia coli membranes correlates with their ability to permeate membranes without complete membrane disruption and kill E. coli cells. Our findings suggest that these polymers operate with a concentration-dependent mechanism of action: at low concentrations permeation and DNA binding occur without membrane disruption, while at high concentrations complete disruption of the membrane occurs. This article is part of a Special Issue entitled: Interfacially Active Peptides and Proteins. Guest Editors: William C. Wimley and Kalina Hristova.
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Affiliation(s)
- Michelle W Lee
- Department of Bioengineering, University of California, Los Angeles, CA 90095, United States
| | - Saswata Chakraborty
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, United States
| | - Nathan W Schmidt
- Department of Bioengineering, University of California, Los Angeles, CA 90095, United States
| | - Rajan Murgai
- Department of Bioengineering, University of California, Los Angeles, CA 90095, United States
| | - Samuel H Gellman
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, United States
| | - Gerard C L Wong
- Department of Bioengineering, University of California, Los Angeles, CA 90095, United States; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, United States; California NanoSystems Institute, University of California, Los Angeles, CA 90095, United States.
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143
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Mutwiri G, Gerdts V, van Drunen Littel-van den Hurk S, Auray G, Eng N, Garlapati S, Babiuk LA, Potter A. Combination adjuvants: the next generation of adjuvants? Expert Rev Vaccines 2014; 10:95-107. [DOI: 10.1586/erv.10.154] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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144
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Leitgeb B. Characteristic Structural Features of Indolicidin: Effects of thecis-transIsomerism on its Conformation. Chem Biol Drug Des 2013; 83:132-40. [DOI: 10.1111/cbdd.12238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 09/03/2013] [Accepted: 09/23/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Balázs Leitgeb
- Institute of Biophysics; Biological Research Centre; Hungarian Academy of Sciences; Temesvári krt. 62 H-6726 Szeged Hungary
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145
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Antimicrobial peptides. Pharmaceuticals (Basel) 2013; 6:1543-75. [PMID: 24287494 PMCID: PMC3873676 DOI: 10.3390/ph6121543] [Citation(s) in RCA: 847] [Impact Index Per Article: 77.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 11/21/2013] [Accepted: 11/25/2013] [Indexed: 12/20/2022] Open
Abstract
The rapid increase in drug-resistant infections has presented a serious challenge to antimicrobial therapies. The failure of the most potent antibiotics to kill “superbugs” emphasizes the urgent need to develop other control agents. Here we review the history and new development of antimicrobial peptides (AMPs), a growing class of natural and synthetic peptides with a wide spectrum of targets including viruses, bacteria, fungi, and parasites. We summarize the major types of AMPs, their modes of action, and the common mechanisms of AMP resistance. In addition, we discuss the principles for designing effective AMPs and the potential of using AMPs to control biofilms (multicellular structures of bacteria embedded in extracellular matrixes) and persister cells (dormant phenotypic variants of bacterial cells that are highly tolerant to antibiotics).
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146
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Mulder KCL, Lima LA, Miranda VJ, Dias SC, Franco OL. Current scenario of peptide-based drugs: the key roles of cationic antitumor and antiviral peptides. Front Microbiol 2013; 4:321. [PMID: 24198814 PMCID: PMC3813893 DOI: 10.3389/fmicb.2013.00321] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 10/11/2013] [Indexed: 01/21/2023] Open
Abstract
Cationic antimicrobial peptides (AMPs) and host defense peptides (HDPs) show vast potential as peptide-based drugs. Great effort has been made in order to exploit their mechanisms of action, aiming to identify their targets as well as to enhance their activity and bioavailability. In this review, we will focus on both naturally occurring and designed antiviral and antitumor cationic peptides, including those here called promiscuous, in which multiple targets are associated with a single peptide structure. Emphasis will be given to their biochemical features, selectivity against extra targets, and molecular mechanisms. Peptides which possess antitumor activity against different cancer cell lines will be discussed, as well as peptides which inhibit virus replication, focusing on their applications for human health, animal health and agriculture, and their potential as new therapeutic drugs. Moreover, the current scenario for production and the use of nanotechnology as delivery tool for both classes of cationic peptides, as well as the perspectives on improving them is considered.
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Affiliation(s)
- Kelly C L Mulder
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Centro de Análises Proteômicas e Bioquímicas, Universidade Católica de Brasília Brasília, Brazil
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147
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Lee JK, Park SC, Hahm KS, Park Y. A helix-PXXP-helix peptide with antibacterial activity without cytotoxicity against MDRPA-infected mice. Biomaterials 2013; 35:1025-39. [PMID: 24176194 DOI: 10.1016/j.biomaterials.2013.10.035] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 10/08/2013] [Indexed: 10/26/2022]
Abstract
In response to the growing problem of multidrug-resistant pathogenic microbes, much attention is being paid to naturally occurring and synthetic antimicrobial peptides (AMPs) and the effects of their structural modification. Among these modifications, amino acid substitution is a simple approach to enhancing biological activity and reducing cytotoxicity. An earlier study indicated that HPA3, an analog of HP (2-20) derived from the N-terminus of Helicobacter pylori ribosomal protein L1, forms large pores and shows considerable cytotoxicity. However, HPA3P, in which a proline (Pro) is substituted for glutamic acid (Glu) at position 9 of HPA3, shows markedly less cytotoxicity. This may be attributable to the presence of a Pro-kink into middle of the HPA3P structure within the membrane environment. Unfortunately, HPA3P is not an effective antibacterial agent in vivo. We therefore designed a helix-PXXP-helix structure (HPA3P2), in which Pro was substituted for the Glu and phenylalanine (Phe) at positions 9 and 12 of HPA3, yielding a molecule with a flexible central hinge. As compared to HPA3P, HPA3P3 exhibited dramatically increased antibacterial activity in vivo. ICR mice infected with clinically isolated multidrug-resistant Pseudomonas aeruginosa showed 100% survival when administered one 0.5-mg/kg dose of HPA3P2 or three 0.1-mg/kg doses of HPA3P2. Moreover, in a mouse model of septic shock induced by P. aeruginosa LPS, HPA3P2 reduced production of pro-inflammatory mediators and correspondingly reduced lung (alveolar) and liver tissue damage. The changes in HPA3 behavior with the introduction of Pro likely reflects alterations of the mechanism of action: i) HPA3 forms pores in the bacterial cell membranes, ii) HPA3P permeates the cell membranes and binds to intracellular RNA and DNA, and iii) HPA3P2 acts on the outer cellular membrane component LPS. Collectively, these results suggest HPA3P2 has the potential to be an effective antibiotic for use against multidrug-resistant bacterial strains.
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Affiliation(s)
- Jong-Kook Lee
- Research Center for Proteinaceous Materials (RCPM), Chosun University, Kwangju 501-759, Republic of Korea
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148
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Alfred RL, Palombo EA, Panozzo JF, Bhave M. The antimicrobial domains of wheat puroindolines are cell-penetrating peptides with possible intracellular mechanisms of action. PLoS One 2013; 8:e75488. [PMID: 24098387 PMCID: PMC3788796 DOI: 10.1371/journal.pone.0075488] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 08/14/2013] [Indexed: 11/19/2022] Open
Abstract
The puroindoline proteins (PINA and PINB) of wheat display lipid-binding properties which affect the grain texture, a critical parameter for wheat quality. Interestingly, the same proteins also display antibacterial and antifungal properties, attributed mainly to their Tryptophan-rich domain (TRD). Synthetic peptides based on this domain also display selectivity towards bacterial and fungal cells and do not cause haemolysis of mammalian cells. However, the mechanisms of these activities are unclear, thus limiting our understanding of the in vivo roles of PINs and development of novel applications. This study investigated the mechanisms of antimicrobial activities of synthetic peptides based on the TRD of the PINA and PINB proteins. Calcein dye leakage tests and transmission electron microscopy showed that the peptides PuroA, Pina-M and Pina-W→F selectively permeabilised the large unilamellar vesicles (LUVs) made with negatively charged phospholipids mimicking bacterial membranes, but were ineffective against LUVs made with zwitterionic phospholipids mimicking eukaryotic membranes. Propidium iodide fluorescence tests of yeast (Saccharomyces cerevisiae) cells showed the peptides were able to cause loss of membrane integrity, PuroA and Pina-M being more efficient. Scanning electron micrographs of PINA-based peptide treated yeast cells showed the formation of pits or pores in cell membranes and release of cellular contents. Gel retardation assays indicated the peptides were able to bind to DNA in vitro, and the induction of filamental growth of E. coli cells indicated in vivo inhibition of DNA synthesis. Together, the results strongly suggest that the PIN-based peptides exert their antimicrobial effects by pore formation in the cell membrane, likely by a carpet-like mechanism, followed by intracellular mechanisms of activity.
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Affiliation(s)
- Rebecca L. Alfred
- Environment and Biotechnology Centre, Faculty of Life and Social Sciences, Swinburne University of Technology, Melbourne, Victoria, Australia
| | - Enzo A. Palombo
- Environment and Biotechnology Centre, Faculty of Life and Social Sciences, Swinburne University of Technology, Melbourne, Victoria, Australia
| | - Joseph F. Panozzo
- Department of Environment and Primary Industries, Horsham, Victoria, Australia
| | - Mrinal Bhave
- Environment and Biotechnology Centre, Faculty of Life and Social Sciences, Swinburne University of Technology, Melbourne, Victoria, Australia
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149
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Sharma R, Lomash S, Salunke DM. Putative bioactive motif of tritrpticin revealed by an antibody with biological receptor-like properties. PLoS One 2013; 8:e75582. [PMID: 24086578 PMCID: PMC3782441 DOI: 10.1371/journal.pone.0075582] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 08/16/2013] [Indexed: 11/18/2022] Open
Abstract
Antimicrobial peptides represent one of the most promising future strategies for combating infections and microbial drug resistance. Tritrpticin is a 13mer tryptophan-rich cationic antimicrobial peptide with a broad spectrum of activity whose application in antimicrobial therapy has been hampered by ambiguity about its biological target and consequently the molecular interactions necessary for its antimicrobial activity. The present study provides clues about the mechanism of action of tritripticin by using a unique monoclonal antibody (mAb) as a 'physiological' structural scaffold. A pool of mAbs were generated against tritrpticin and based on its high affinity and ability to bind tritrpticin analogs, mAb 6C6D7 was selected and characterized further. In a screening of phage displayed random peptides, this antibody was able to identify a novel antimicrobial peptide with low sequence homology to tritrpticin, suggesting that the mAb possessed the physico-chemical characteristics mimicking the natural receptor. Subsequently, thermodynamics and molecular modeling identified a core group of hydrophobic residues in tritrpticin arranged in a distorted's' shaped conformation as critical for antibody binding. Comparison of the mAb induced conformation with the micelle bound structure of tritrpticin reveals how a common motif may be able to interact with multiple classes of biomolecules thus extending the target range of this innate immune peptide. Based on the concurrence between thermodynamic and structural data our results reveal a template that can be used to design novel antimicrobial pharmacophores while simultaneously demonstrating at a more fundamental level the potential of mAbs to act as receptor surrogates.
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Affiliation(s)
| | | | - Dinakar M. Salunke
- National Institute of Immunology, New Delhi, India
- Regional Centre for Biotechnology, Gurgaon, India
- * E-mail:
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150
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Synthesis of side chain N,N'-diaminoalkylated derivatives of basic amino acids for application in solid-phase peptide synthesis. Methods Mol Biol 2013; 1081:61-75. [PMID: 24014434 DOI: 10.1007/978-1-62703-652-8_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Despite the enormous therapeutic potential, the clinical use of peptides has been limited by their poor bioavailability and low stability under physiological conditions. Hence, efforts have been undertaken to alter peptide structure in ways to improve their pharmacological properties. Inspired by the importance of basic amino acids in biological systems and the remarkable versatility displayed by lysine during the synthesis of complex peptide scaffolds, this chapter describes a simple procedure that enables rapid access to protected N,N'-diaminoalkylated basic amino acid building blocks suitable for standard solid-phase peptide synthesis. This procedure allows preparation of symmetrical, as well as unsymmetrical, dialkylated amino acid derivatives that can be further modified, enhancing their synthetic utility. The suitability of the synthesized branched basic amino acid building blocks for use in standard solid-phase peptide synthesis has been demonstrated by synthesis of an indolicidin analog in which the lysine residue was substituted with its synthetic polyamino derivate. The substitution provided indolicidin analog with increase net positive charge, more ordered secondary structure in biological membranes mimicking conditions, and enhanced antibacterial activity without altering hemolytic activity. Taking into consideration the increasing interest for peptides with unusual structural features due to their improved biological properties, the described synthesis of polyfunctional amino acid building blocks is of particular practical value.
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