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He L, Zhang T, Zhu C, Yan T, Liu J. Crown Ether-Based Ion Transporters in Bilayer Membranes. Chemistry 2023; 29:e202300044. [PMID: 36723493 DOI: 10.1002/chem.202300044] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 01/28/2023] [Accepted: 01/30/2023] [Indexed: 02/02/2023]
Abstract
Bilayer membranes that enhance the stability of the cell are essential for cell survival, separating and protecting the interior of the cell from its external environment. Membrane-based channel proteins are crucial for sustaining cellular activities. However, dysfunction of these proteins would induce serial channelopathies, which could be substituted by artificial ion channel analogs. Crown ethers (CEs) are widely studied in the area of artificial ion channels owing to their intrinsic host-guest interaction with different kinds of organic and inorganic ions. Other advantages such as lower price, chemical stability, and easier modification also make CE a research hotspot in the field of synthetic transmembrane nanopores. And numerous CEs-based membrane-active synthetic ion channels were designed and fabricated in the past decades. Herein, the recent progress of CEs-based synthetic ion transporters has been comprehensively summarized in this review, including their design principles, functional mechanisms, controllable properties, and biomedical applications. Furthermore, this review has been concluded by discussing the future opportunities and challenges facing this research field. It is anticipated that this review could offer some inspiration for the future fabrication of novel CEs-derived ion transporters with more advanced structures, properties, and practical applications.
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Affiliation(s)
- Lei He
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, 311121, Hangzhou, P. R. China
| | - Tianlong Zhang
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, 311121, Hangzhou, P. R. China
| | - Canhong Zhu
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, 311121, Hangzhou, P. R. China
| | - Tengfei Yan
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, 311121, Hangzhou, P. R. China
| | - Junqiu Liu
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, 311121, Hangzhou, P. R. China
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2
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Self-assembled Supramolecular Artificial Transmembrane Ion Channels: Recent Progress and Application. Chem Res Chin Univ 2023. [DOI: 10.1007/s40242-023-2337-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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3
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Yan T, Liu S, Luo Y, Zou Y, Liu J. Research Progress on the Macrocycle-Derived Artificial Transmembrane Ion Channels. ACTA CHIMICA SINICA 2021. [DOI: 10.6023/a21050222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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4
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Xin P, Zhao L, Mao L, Xu L, Hou S, Kong H, Fang H, Zhu H, Jiang T, Chen CP. Effect of charge status on the ion transport and antimicrobial activity of synthetic channels. Chem Commun (Camb) 2020; 56:13796-13799. [DOI: 10.1039/d0cc05730d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The charge status of channels formed by pillararene–gramicidin hybrid molecules has a significant impact on their trans-membrane transport properties, membrane-association abilities and antimicrobial activities.
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5
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Effects of the peptide Magainin H2 on Supported Lipid Bilayers studied by different biophysical techniques. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2635-2643. [DOI: 10.1016/j.bbamem.2018.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 10/02/2018] [Indexed: 11/24/2022]
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6
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Xin P, Sun Y, Kong H, Wang Y, Tan S, Guo J, Jiang T, Dong W, Chen CP. A unimolecular channel formed by dual helical peptide modified pillar[5]arene: correlating transmembrane transport properties with antimicrobial activity and haemolytic toxicity. Chem Commun (Camb) 2017; 53:11492-11495. [DOI: 10.1039/c7cc06697j] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Five unimolecular channels with different lengths are presented. The varying length of these channels has significant impact on their transport properties.
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Affiliation(s)
- Pengyang Xin
- Henan Engineering Laboratory of Chemical Pharmaceuticals & Biomedical Materials
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
| | - Yonghui Sun
- Henan Engineering Laboratory of Chemical Pharmaceuticals & Biomedical Materials
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
| | - Huiyuan Kong
- Henan Engineering Laboratory of Chemical Pharmaceuticals & Biomedical Materials
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
| | - Yaodong Wang
- Henan Engineering Laboratory of Chemical Pharmaceuticals & Biomedical Materials
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
| | - Si Tan
- Henan Engineering Laboratory of Chemical Pharmaceuticals & Biomedical Materials
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
| | - Jingjing Guo
- Henan Engineering Laboratory of Chemical Pharmaceuticals & Biomedical Materials
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
| | - Tao Jiang
- Henan Engineering Laboratory of Chemical Pharmaceuticals & Biomedical Materials
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
| | - Wenpei Dong
- Henan Engineering Laboratory of Chemical Pharmaceuticals & Biomedical Materials
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
| | - Chang-Po Chen
- Henan Engineering Laboratory of Chemical Pharmaceuticals & Biomedical Materials
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
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Common Mechanism of Cross-Resistance Development in Pathogenic Bacteria Bacillus cereus Against Alamethicin and Pediocin Involves Alteration in Lipid Composition. Curr Microbiol 2016; 73:534-41. [DOI: 10.1007/s00284-016-1090-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/21/2016] [Indexed: 10/21/2022]
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8
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Shi WL, Chen XL, Wang LX, Gong ZT, Li S, Li CL, Xie BB, Zhang W, Shi M, Li C, Zhang YZ, Song XY. Cellular and molecular insight into the inhibition of primary root growth of Arabidopsis induced by peptaibols, a class of linear peptide antibiotics mainly produced by Trichoderma spp. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:2191-205. [PMID: 26850879 PMCID: PMC4809282 DOI: 10.1093/jxb/erw023] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Trichoderma spp. are well known biocontrol agents that produce a variety of antibiotics. Peptaibols are a class of linear peptide antibiotics mainly produced by Trichoderma Alamethicin, the most studied peptaibol, is reported as toxic to plants at certain concentrations, while the mechanisms involved are unclear. We illustrated the toxic mechanisms of peptaibols by studying the growth-inhibitory effect of Trichokonin VI (TK VI), a peptaibol from Trichoderma longibrachiatum SMF2, on Arabidopsis primary roots. TK VI inhibited root growth by suppressing cell division and cell elongation, and disrupting root stem cell niche maintenance. TK VI increased auxin content and disrupted auxin response gradients in root tips. Further, we screened the Arabidopsis TK VI-resistant mutant tkr1. tkr1 harbors a point mutation in GORK, which encodes gated outwardly rectifying K(+)channel proteins. This mutation alleviated TK VI-induced suppression of K(+)efflux in roots, thereby stabilizing the auxin gradient. The tkr1 mutant also resisted the phytotoxicity of alamethicin. Our results indicate that GORK channels play a key role in peptaibol-plant interaction and that there is an inter-relationship between GORK channels and maintenance of auxin homeostasis. The cellular and molecular insight into the peptaibol-induced inhibition of plant root growth advances our understanding of Trichoderma-plant interactions.
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Affiliation(s)
- Wei-Ling Shi
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research, Shandong University, Jinan 250100, China State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research, Shandong University, Jinan 250100, China
| | - Li-Xia Wang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research, Shandong University, Jinan 250100, China
| | - Zhi-Ting Gong
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research, Shandong University, Jinan 250100, China
| | - Shuyu Li
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Chun-Long Li
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan 250100, China
| | - Bin-Bin Xie
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research, Shandong University, Jinan 250100, China
| | - Wei Zhang
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan 250100, China
| | - Mei Shi
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research, Shandong University, Jinan 250100, China
| | - Chuanyou Li
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yu-Zhong Zhang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research, Shandong University, Jinan 250100, China
| | - Xiao-Yan Song
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research, Shandong University, Jinan 250100, China
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9
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Barns KJ, Weisshaar JC. Single-cell, time-resolved study of the effects of the antimicrobial peptide alamethicin on Bacillus subtilis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:725-32. [PMID: 26777771 DOI: 10.1016/j.bbamem.2016.01.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 01/05/2016] [Accepted: 01/07/2016] [Indexed: 12/14/2022]
Abstract
Alamethicin is a well-studied antimicrobial peptide (AMP) that kills Gram-positive bacteria. It forms narrow, barrel-stave pores in planar lipid bilayers. We present a detailed, time-resolved microscopy study of the sequence of events during the attack of alamethicin on individual, live Bacillus subtilis cells expressing GFP in the cytoplasm. At the minimum inhibitory concentration (MIC), the first observed symptom is the halting of growth, as judged by the plateau in measured cell length vs time. The data strongly suggest that this growth-halting event occurs prior to membrane permeabilization. Gradual degradation of the proton-motive force, inferred from a decrease in pH-dependent GFP fluorescence intensity, evidently begins minutes later and continues over about 5 min. There follows an abrupt permeabilization of the cytoplasmic membrane to the DNA stain Sytox Orange and concomitant loss of small osmolytes, causing observable cell shrinkage, presumably due to decreased turgor pressure. This permeabilization of the cytoplasmic membrane occurs uniformly across the entire membrane, not locally, on a timescale of 5s or less. GFP gradually leaks out of the cell envelope, evidently impeded by the shrunken peptidoglycan layer. Disruption of the cell envelope by alamethicin occurs in stages, with larger and larger species permeating the envelope as time evolves over tens of minutes. Some of the observed symptoms are consistent with the formation of barrel-stave pores, but the data do not rule out "chaotic pore" or "carpet" mechanisms. We contrast the effects of alamethicin and the human cathelicidin LL-37 on B. subtilis.
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Affiliation(s)
- Kenneth J Barns
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - James C Weisshaar
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA; Molecular Biophysics Program, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA.
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10
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Development and validation of LC–MS methods for peptaibol quantification in fungal extracts according to their lengths. J Chromatogr B Analyt Technol Biomed Life Sci 2016; 1009-1010:25-33. [DOI: 10.1016/j.jchromb.2015.11.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/20/2015] [Accepted: 11/21/2015] [Indexed: 01/31/2023]
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11
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Lohan S, Cameotra SS, Bisht GS. Antibacterial evaluation of structurally amphipathic, membrane active small cationic peptidomimetics: Synthesized by incorporating 3-amino benzoic acid as peptidomimetic element. Eur J Med Chem 2014; 83:102-15. [DOI: 10.1016/j.ejmech.2014.06.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 06/06/2014] [Accepted: 06/12/2014] [Indexed: 10/25/2022]
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12
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Mehla J, Sood SK. Substantiation in Enterococcus faecalis of dose-dependent resistance and cross-resistance to pore-forming antimicrobial peptides by use of a polydiacetylene-based colorimetric assay. Appl Environ Microbiol 2011; 77:786-93. [PMID: 21115699 PMCID: PMC3028714 DOI: 10.1128/aem.01496-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 11/15/2010] [Indexed: 11/20/2022] Open
Abstract
A better understanding of the antimicrobial peptide (AMP) resistance mechanisms of bacteria will facilitate the design of effective and potent AMPs. Therefore, to understand resistance mechanisms and for in vitro assessment, variants of Enterococcus faecalis that are resistant to different doses of the fungal AMP alamethicin (Alm(r)) were selected and characterized. The resistance developed was dose dependent, as both doses of alamethicin and degrees of resistance were colinear. The formation of bacterial cell aggregates observed in resistant cells may be the prime mechanism of resistance because overall, a smaller cell surface in aggregated cells is exposed to AMPs. Increased rigidity of the membranes of Alm(r) variants, because of their altered fatty acids, was correlated with limited membrane penetration by alamethicin. Thus, resistance developed against alamethicin was an adaptation of the bacterial cells through changes in their morphological features and physiological activity and the composition of membrane phospholipids. The Alm(r) variants showed cross-resistance to pediocin, which indicated that resistance developed against both AMPs may share a mechanism, i.e., an alteration in the cell membrane. High percentages of colorimetric response by both AMPs against polydiacetylene/lipid biomimetic membranes of Alm(r) variants confirmed that altered phospholipid and fatty acid compositions were responsible for acquisition of resistance. So far, this is the only report of quantification of resistance and cross-resistance using an in vitro colorimetric approach. Our results imply that a single AMP or AMP analog may be effective against bacterial strains having a common mechanism of resistance. Therefore, an understanding of resistance would contribute to the development of a single efficient, potent AMP against resistant strains that share a mechanism of resistance.
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Affiliation(s)
- Jitender Mehla
- Animal Biochemistry Division, National Dairy Research Institute, Karnal-132001, Haryana, India.
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13
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Azevedo Calderon LD, Silva ADAE, Ciancaglini P, Stábeli RG. Antimicrobial peptides from Phyllomedusa frogs: from biomolecular diversity to potential nanotechnologic medical applications. Amino Acids 2010; 40:29-49. [PMID: 20526637 DOI: 10.1007/s00726-010-0622-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 05/05/2010] [Indexed: 10/19/2022]
Abstract
Screening for new bioactive peptides in South American anurans has been pioneered in frogs of the genus Phyllomedusa. All frogs of this genus have venomous skin secretions, i.e., a complex mixture of bioactive peptides against potential predators and pathogens that presumably evolved in a scenario of predator-prey interaction and defense against microbial invasion. For every new anuran species studied new peptides are found, with homologies to hormones, neurotransmitters, antimicrobials, and several other peptides with unknown biological activity. From Vittorio Erspamer findings, this genus has been reported as a "treasure store" of bioactive peptides, and several groups focus their research on these species. From 1966 to 2009, more than 200 peptide sequences from different Phyllomedusa species were deposited in UniProt and other databases. During the last decade, the emergence of high-throughput molecular technologies involving de novo peptide sequencing via tandem mass spectrometry, cDNA cloning, pharmacological screening, and surface plasmon resonance applied to peptide discovery, led to fast structural data acquisition and the generation of peptide molecular libraries. Research groups on bioactive peptides in Brazil using these new technologies, accounted for the exponential increase of new molecules described in the last decade, much higher than in any previous decades. Recently, these secretions were also reported as a rich source of multiple antimicrobial peptides effective against multidrug resistant strains of bacteria, fungi, protozoa, and virus, providing instructive lessons for the development of new and more efficient nanotechnological-based therapies for infectious diseases treatment. Therefore, novel drugs arising from the identification and analysis of bioactive peptides from South American anuran biodiversity have a promising future role on nanobiotechnology.
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Affiliation(s)
- Leonardo de Azevedo Calderon
- Centro de Estudos de Biomoléculas Aplicadas a Medicina "Professor Dr. José Roberto Giglio" (CEBio), Núcleo de Saúde (NUSAU), Universidade Federal de Rondônia (UNIR), Porto Velho, RO, 76800-000, Brazil
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14
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Thippeswamy HS, Sood SK, Venkateswarlu R, Raj I. Membranes of five-fold alamethicin-resistantStaphylococcus aureus, Enterococcus faecalis andBacillus cereus show decreased interactions with alamethicin due to changes in membrane fluidity and surface charge. ANN MICROBIOL 2009. [DOI: 10.1007/bf03175151] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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15
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Kaderbhai NN, Khan T, Kaderbhai MA. An Anti-microbial Peptide Derivative of Flesh Fruit Fly Mimics Secretory Signal Sequence and Inhibits Signal Peptidase-I in the Export Pathway. Int J Pept Res Ther 2008. [DOI: 10.1007/s10989-008-9128-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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16
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Leitgeb B, Szekeres A, Manczinger L, Vágvölgyi C, Kredics L. The history of alamethicin: a review of the most extensively studied peptaibol. Chem Biodivers 2007; 4:1027-51. [PMID: 17589875 DOI: 10.1002/cbdv.200790095] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Balázs Leitgeb
- Institute of Biophysics, Biological Research Center of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged, Hungary
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Rippa S, Adenier H, Derbaly M, Béven L. The peptaibol alamethicin induces an rRNA-cleavage-associated death in Arabidopsis thaliana. Chem Biodivers 2007; 4:1360-73. [PMID: 17589869 DOI: 10.1002/cbdv.200790116] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The plant-metabolic response to amphipathic peptides produced by the soil fungi of the genus Trichoderma remains largely unknown. The present investigation was undertaken to examine the death process in alamethicin-treated Arabidopsis thaliana plantlets. The rapid death triggered by alamethicin (at 50 microM) was shown to be associated with protein-synthesis arrest and with specific cleavage of 18S and 25S ribosomal RNA. The use of an inhibitor of nitric oxide (NO) synthases and of an NO scavenger suggested that rRNA cleavage was suppressed by NO. Experiments conducted with a synthetic alamethicin analogue, in which all alpha-aminoisobutyric acid (Aib) residues have been replaced by leucine moieties, showed that the non-coded residues are essential for the ability of the peptaibol to induce rRNA cleavage in Arabidopsis. Our data indicate that further investigations on the mode of action of alamethicin in planta could be of great interest to study the death-signaling pathway associated with rRNA degradation in plants.
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Affiliation(s)
- Sonia Rippa
- Université de Technologie de Compiègne, CNRS, UMR 6022 Génie Enzymatique et Cellulaire, Compiègne Cedex, France
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Abstract
The development and antimicrobial properties of peptaibiotics and peptaibols are discussed. Also, the role of emerging peptaibol analogues, of alamethicin, e.g., harzianins HC, trichotoxin, and antiamoebin, is outlined.
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Affiliation(s)
- Hervé Duclohier
- UMR 6187 CNRS, Université de Poitiers, Pôle Biologie Santé, Poitiers, France.
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19
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Abstract
AbstractAntibiotic resistance is increasing at a rate that far exceeds the pace of new development of drugs. Antimicrobial peptides, both synthetic and from natural sources, have raised interest as pathogens become resistant against conventional antibiotics. Indeed, one of the major strengths of this class of molecules is their ability to kill multidrug-resistant bacteria. Antimicrobial peptides are relatively small (6 to 100 aminoacids), amphipathic molecules of variable length, sequence and structure with activity against a wide range of microorganisms including bacteria, protozoa, yeast, fungi, viruses and even tumor cells. They usually act through relatively non-specific mechanisms resulting in membranolytic activity but they can also stimulate the innate immune response. Several peptides have already entered pre-clinical and clinical trials for the treatment of catheter site infections, cystic fibrosis, acne, wound healing and patients undergoing stem cell transplantation. We review the advantages of these molecules in clinical applications, their disadvantages including their low in vivo stability, high costs of production and the strategies for their discovery and optimization.
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Abstract
Antimicrobial peptides are ancient components of the innate immune system and have been isolated from organisms spanning the phylogenetic spectrum. Over an evolutionary time span, these peptides have retained potency, in the face of highly mutable target microorganisms. This fact suggests important coevolutionary influences in the host-pathogen relationship. Despite their diverse origins, the majority of antimicrobial peptides have common biophysical parameters that are likely essential for activity, including small size, cationicity, and amphipathicity. Although more than 900 different antimicrobial peptides have been characterized, most can be grouped as belonging to one of three structural classes: (1) linear, often of alpha-helical propensity; (2) cysteine stabilized, most commonly conforming to beta-sheet structure; and (3) those with one or more predominant amino acid residues, but variable in structure. Interestingly, these biophysical and structural features are retained in ribosomally as well as nonribosomally synthesized peptides. Therefore, it appears that a relatively limited set of physicochemical features is required for antimicrobial peptide efficacy against a broad spectrum of microbial pathogens. During the past several years, a number of themes have emerged within the field of antimicrobial peptide immunobiology. One developing area expands upon known microbicidal mechanisms of antimicrobial peptides to include targets beyond the plasma membrane. Examples include antimicrobial peptide activity involving structures such as extracellular polysaccharide and cell wall components, as well as the identification of an increasing number of intracellular targets. Additional areas of interest include an expanding recognition of antimicrobial peptide multifunctionality, and the identification of large antimicrobial proteins, and antimicrobial peptide or protein fragments derived thereof. The following discussion highlights such recent developments in antimicrobial peptide immunobiology, with an emphasis on the biophysical aspects of host-defense polypeptide action and mechanisms of microbial resistance.
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Affiliation(s)
- Nannette Y Yount
- Division of Infectious Diseases, Harbor-UCLA Medical Center, Torrance, CA 90509, USA
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Salditt T, Li C, Spaar A. Structure of antimicrobial peptides and lipid membranes probed by interface-sensitive X-ray scattering. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:1483-98. [DOI: 10.1016/j.bbamem.2006.08.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Revised: 08/04/2006] [Accepted: 08/04/2006] [Indexed: 10/24/2022]
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22
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Li C, Salditt T. Structure of magainin and alamethicin in model membranes studied by x-ray reflectivity. Biophys J 2006; 91:3285-300. [PMID: 16920839 PMCID: PMC1614476 DOI: 10.1529/biophysj.106.090118] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have investigated the structure of lipid bilayers containing varied molar ratios of different lipids and the antimicrobial peptides magainin and alamethicin. For this structural study, we have used x-ray reflectivity on highly aligned solid-supported multilamellar lipid membranes. The reflectivity curves have been analyzed by semi-kinematical reflectivity theory modeling the bilayer density profile rho(z). Model simulations of the reflectivity curves cover a large range of vertical momentum transfer q(z), and yield excellent agreement between data and theory. The structural changes observed as a function of the molar peptide/lipid concentration P/L are discussed in a comparative way.
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Affiliation(s)
- C Li
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany
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23
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Duclohier H. Bilayer lipid composition modulates the activity of dermaseptins, polycationic antimicrobial peptides. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2006; 35:401-9. [PMID: 16477458 DOI: 10.1007/s00249-006-0047-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 01/17/2006] [Accepted: 01/30/2006] [Indexed: 10/25/2022]
Abstract
The primary targets of defense peptides are plasma membranes, and the induced irreversible depolarization is sufficient to exert antimicrobial activity although secondary modes of action might be at work. Channels or pores underlying membrane permeabilization are usually quite large with single-channel conductances two orders of magnitude higher than those exhibited by physiological channels involved, e.g., in excitability. Accordingly, the ion specificity and selectivity are quite low. Whereas, e.g., peptaibols favor cation transport, polycationic or basic peptides tend to form anion-specific pores. With dermaseptin B2, a 33 residue long and mostly alpha-helical peptide isolated from the skin of the South American frog Phyllomedusa bicolor, we found that the ion specificity of its pores induced in bilayers is modulated by phospholipid-charged headgroups. This suggests mixed lipid-peptide pore lining instead of the more classical barrel-stave model. Macroscopic conductance is nearly voltage independent, and concentration dependence suggests that the pores are mainly formed by dermaseptin tetramers. The two most probable single-channel events are well resolved at 200 and 500 pS (in 150 mM NaCl) with occasional other equally spaced higher or lower levels. In contrast to previous molecular dynamics previsions, this study demonstrates that dermaseptins are able to form pores, although a related analog (B6) failed to induce any significant conductance. Finally, the model of the pore we present accounts for phospholipid headgroups intercalated between peptide helices lining the pore and for one of the most probable single-channel conductance.
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Affiliation(s)
- Hervé Duclohier
- Institut de Physiologie et de Biologie Cellulaires (Pôle Biologie Santé), UMR 6187 CNRS-Université de Poitiers, 40 Avenue du Recteur Pineau, 86022, Poitiers, France.
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Szekeres A, Leitgeb B, Kredics L, Antal Z, Hatvani L, Manczinger L, Vágvölgyi C. Peptaibols and related peptaibiotics of Trichoderma. A review. Acta Microbiol Immunol Hung 2005; 52:137-68. [PMID: 16003936 DOI: 10.1556/amicr.52.2005.2.2] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Peptaibols and the related peptaibiotics are linear, amphipathic polypeptides. More than 300 of these secondary metabolites have been described to date. These compounds are composed of 5-20 amino acids and are generally produced in microheterogeneous mixtures. Peptaibols and peptaibiotics with unusual amino acid content are the result of non-ribosomal biosynthesis. Large multifunctional enzymes known as peptide synthetases assemble these molecules by the multiple carrier thiotemplate mechanism from a remarkable range of precursors, which can be N-methylated, acylated or reduced. Peptaibols and peptaibiotics show interesting physico-chemical and biological properties including the formation of pores in bilayer lipid membranes, as well as antibacterial, antifungal, occasionally antiviral activities, and may elicit plant resistance. The three-dimensional structure of peptaibols and peptaibiotics is characterized predominantly by one type of the helical motifs alpha-helix, 3(10)-helix and beta-bend ribbon spiral. The aim of this review is to summarize the data available about the biosynthesis, biological activity and conformational properties of peptaibols and peptaibiotics described from Trichoderma species.
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Affiliation(s)
- A Szekeres
- Department of Microbiology, Faculty of Sciences, University of Szeged, P.O. Box 533, H-6701 Szeged, Hungary
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Duclohier H, Alder GM, Bashford CL, Brückner H, Chugh JK, Wallace BA. Conductance studies on trichotoxin_A50E and implications for channel structure. Biophys J 2005; 87:1705-10. [PMID: 15345549 PMCID: PMC1304575 DOI: 10.1529/biophysj.104.040659] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Trichotoxin_A50E is an 18-residue peptaibol whose crystal structure has recently been determined. In this study, the conductance properties of trichotoxin_A50E have been investigated in neutral planar lipid bilayers. The macroscopic current-voltage curves disclose a moderate voltage-sensitivity and the concentration-dependence suggests the channels are primarily hexameric. Under ion gradients, shifts of the reversal potential indicate that cations are preferentially transported. Trichotoxin displays only one single-channel conductance state in a given experiment, but an ensemble of experiments reveals a distribution of conductance levels. This contrasts with the related peptaibol alamethicin, which produces multiple channel levels in a single experiment, indicative of recruitment of additional monomers into different multimeric-sized channels. Based on these conductance measurements and on the recently available crystal structure of trichotoxin_A50E, which is a shorter and straighter helix than alamethicin, a tightly-packed hexameric model structure has been constructed for the trichotoxin channel. It has molecular dimensions and surface electrostatic potential compatible with the observed conductance properties of the most probable and longer-lived channel.
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Affiliation(s)
- H Duclohier
- Interactions Cellulaires et Moléculaires, UMR 6026 Centre National de la Recherche Scientifique-Université de Rennes I, 35042 Rennes Cedex, France.
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Houdai T, Matsuoka S, Morsy N, Matsumori N, Satake M, Murata M. Hairpin conformation of amphidinols possibly accounting for potent membrane permeabilizing activities. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.01.069] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Spaar A, Münster C, Salditt T. Conformation of peptides in lipid membranes studied by x-ray grazing incidence scattering. Biophys J 2005; 87:396-407. [PMID: 15240474 PMCID: PMC1304361 DOI: 10.1529/biophysj.104.040667] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although the antimicrobial, fungal peptide alamethicin has been extensively studied, the conformation of the peptide and the interaction with lipid bilayers as well as the mechanism of channel gating are still not completely clear. As opposed to studies of the crystalline state, the polypeptide structures in the environment of fluid bilayers are difficult to probe. We have investigated the conformation of alamethicin in highly aligned stacks of model lipid membranes by synchrotron-based x-ray scattering. The (wide-angle) scattering distribution has been measured by reciprocal space mappings. A pronounced scattering signal is observed in samples of high molar peptide/lipid ratio which is distinctly different from the scattering distribution of an ideal helix in the transmembrane state. Beyond simple models of ideal helices, the data is analyzed in terms of models based on atomic coordinates from the Brookhaven Protein Data Bank, as well as from published molecular dynamics simulations. The results can be explained by assuming a wide distribution of helix tilt angles with respect to the membrane normal and a partial insertion of the N-terminus into the membrane.
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Affiliation(s)
- Alexander Spaar
- Department of Experimental Physics, Universität des Saarlandes, Saarbruecken, Germany
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Shenkarev ZO, Paramonov AS, Balashova TA, Yakimenko ZA, Baru MB, Mustaeva LG, Raap J, Ovchinnikova TV, Arseniev AS. High stability of the hinge region in the membrane-active peptide helix of zervamicin: paramagnetic relaxation enhancement studies. Biochem Biophys Res Commun 2005; 325:1099-105. [PMID: 15541401 DOI: 10.1016/j.bbrc.2004.10.115] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Indexed: 10/26/2022]
Abstract
Zervamicin IIB is a 16 amino acid peptaibol that forms voltage dependent ion channels with multilevel conductance states in planar lipid bilayers and vesicular systems. Stability of the hinge region and intermolecular interactions were investigated in the N- and C-terminally spin-labelled peptide analogues. Intermolecular and intramolecular paramagnetic enhancement indicates that zervamicin behaves as a rigid helical rod in methanol solution. There are no high amplitude hinge-bending motions, and the peptaibol is monomeric up to concentration 1.5 mM. Stability of the hinge region illustrates the helix stabilising propensity of the Pro residue in membrane mimic environments and implies absence of significant conformational rearrangement due to voltage peptaibol activation.
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Affiliation(s)
- Zakhar O Shenkarev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
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29
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Béven L, Castano S, Dufourcq J, Wieslander A, Wróblewski H. The antibiotic activity of cationic linear amphipathic peptides: lessons from the action of leucine/lysine copolymers on bacteria of the class Mollicutes. EUROPEAN JOURNAL OF BIOCHEMISTRY 2003; 270:2207-17. [PMID: 12752440 DOI: 10.1046/j.1432-1033.2003.03587.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Peptides composed of leucyl and lysyl residues ('LK peptides') with different compositions and sequences were compared for their antibacterial activities using cell wall-less bacteria of the class Mollicutes (acholeplasmas, mycoplasmas and spiroplasmas) as targets. The antibacterial activity of the amphipathic alpha-helical peptides varied with their size, 15 residues being the optimal length, independent of the membrane hydrophobic core thickness and the amount of cholesterol. The 15-residue ideally amphipathic alpha helix with a +5 positive net charge (KLLKLLLKLLLKLLK) had the strongest antibacterial activity, similar to that of melittin. In contrast, scrambled peptides devoid of amphipathy and the less hydrophobic beta-sheeted peptides [(LK)nK], even those 15-residue long, were far less potent than the helical ones. Furthermore, the growth inhibitory activity of the peptides was correlated with their ability to abolish membrane potential. These data are fully consistent with a predominantly flat orientation of LK peptides at the lipid/water interface and strongly supports that these peptides and probably the linear polycationic amphipathic defence peptides act on bacterial membranes in four main steps according to the 'carpet' model: (a) interfacial partitioning with accumulation of monomers on the target membrane (limiting step); (b) peptide structural changes (conformation, aggregation, and orientation) induced by interactions with the lipid bilayer (as already shown with liposomes and erythrocytes); (c) plasma membrane permeabilization/depolarization via a detergent-like effect; and (d) rapid bacterial cell death if the extent of depolarization is maintained above a critical threshold.
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Affiliation(s)
- Laure Béven
- UMR CNRS 6026, Université de Rennes 1, France
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Yin P, Burns CJ, Osman PDJ, Cornell BA. A tethered bilayer sensor containing alamethicin channels and its detection of amiloride based inhibitors. Biosens Bioelectron 2003; 18:389-97. [PMID: 12604256 DOI: 10.1016/s0956-5663(02)00160-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Alamethicin, a small transmembrane peptide, inserts into a tethered bilayer membrane (tBLM) to form ion channels, which we have investigated using electrical impedance spectroscopy. The number of channels formed is dependent on the incubation time, concentration of the alamethicin and the application of DC voltage. The properties of the ion channels when formed in tethered bilayers are similar to those for such channels assembled into black lipid membranes (BLMs). Furthermore, amiloride and certain analogs can inhibit the channel pores, formed in the tBLMs. The potency and concentration of the inhibitors can be determined by measuring the change of impedance. Our work illustrates the possibility of using a synthetic tBLM for the study of small peptide voltage dependent ion channels. A potential application of such a device is as a screening tool in drug discovery processes.
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Affiliation(s)
- Ping Yin
- Australian Membrane Biotechnology Research Institute, 126 Greville Street, Chatswood NSW 2067, Australia.
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Abstract
Antimicrobial peptides have been isolated and characterized from tissues and organisms representing virtually every kingdom and phylum, ranging from prokaryotes to humans. Yet, recurrent structural and functional themes in mechanisms of action and resistance are observed among peptides of widely diverse source and composition. Biochemical distinctions among the peptides themselves, target versus host cells, and the microenvironments in which these counterparts convene, likely provide for varying degrees of selective toxicity among diverse antimicrobial peptide types. Moreover, many antimicrobial peptides employ sophisticated and dynamic mechanisms of action to effect rapid and potent activities consistent with their likely roles in antimicrobial host defense. In balance, successful microbial pathogens have evolved multifaceted and effective countermeasures to avoid exposure to and subvert mechanisms of antimicrobial peptides. A clearer recognition of these opposing themes will significantly advance our understanding of how antimicrobial peptides function in defense against infection. Furthermore, this understanding may provide new models and strategies for developing novel antimicrobial agents, that may also augment immunity, restore potency or amplify the mechanisms of conventional antibiotics, and minimize antimicrobial resistance mechanisms among pathogens. From these perspectives, the intention of this review is to illustrate the contemporary structural and functional themes among mechanisms of antimicrobial peptide action and resistance.
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Affiliation(s)
- Michael R Yeaman
- Division of Infectious Diseases, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA.
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Duclohier H, Alder G, Kociolek K, Leplawy MT. Channel properties of template assembled alamethicin tetramers. J Pept Sci 2003; 9:776-83. [PMID: 14658797 DOI: 10.1002/psc.523] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The multiple conductance levels displayed by the antibiotic alamethicin in planar lipid bilayers is explained by a dynamic 'barrel-stave' model, the conducting pore resulting from the aggregation of up to ten helical amphipathic helical monomers. However, the precise assignment of an oligomerization state to a particular single-channel conductance substate is far from being experimentally clear. In addition, it could be useful to tailor a given channel geometry to selectively allow the permeation of solutes with different molecular sizes, whilst retaining a high voltage-dependence. To control the aggregation state of the channel, the TASP (template assembled synthetic proteins) strategy was applied to synthesize structurally defined oligomers, i.e. dimer, trimer, tetramer. The modulation of conductance properties of three alamethicin tetramers with the length and flexibility of the linkers of the 'open' or linear template is described. It is shown that the introduction of an alanine between the contiguous lysines to which are tethered C-terminally modified alamethicin helical monomers stabilizes the open channel states, whereas the alanine substitution by Pro-Gly, a reverse beta-turn promoting motif, increases voltage-dependence and leads to single-channel conductance values more in line with the expected ones from a tetrameric bundle.
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Affiliation(s)
- Hervé Duclohier
- UMR 6026 CNRS-Université de Rennes I, Bâtiment 13, Campus de Beaulieu, 35042 Rennes, France.
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Yamaguchi H, Kodama H, Osada S, Jelokhani-Niaraki M, Kato F, Kondo M. The Position of Aib Residues Defines the Antimicrobial Activity of Aib-Containing Peptides. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2002. [DOI: 10.1246/bcsj.75.1563] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Castano S, Blaudez D, Desbat B, Dufourcq J, Wróblewski H. Secondary structure of spiralin in solution, at the air/water interface, and in interaction with lipid monolayers. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1562:45-56. [PMID: 11988221 DOI: 10.1016/s0005-2736(02)00366-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The surface of spiroplasmas, helically shaped pathogenic bacteria related to the mycoplasmas, is crowded with the membrane-anchored lipoprotein spiralin whose structure and function are unknown. In this work, the secondary structure of spiralin under the form of detergent-free micelles (average Stokes radius, 87.5 A) in water and at the air/water interface, alone or in interaction with lipid monolayers was analyzed. FT-IR and circular dichroism (CD) spectroscopic data indicate that spiralin in solution contains about 25+/-3% of helices and 38+/-2% of beta sheets. These measurements are consistent with a consensus predictive analysis of the protein sequence suggesting about 28% of helices, 32% of beta sheets and 40% of irregular structure. Brewster angle microscopy (BAM) revealed that, in water, the micelles slowly disaggregate to form a stable and homogeneous layer at the air/water interface, exhibiting a surface pressure up to 10 mN/m. Polarization modulation infrared reflection absorption spectroscopy (PMIRRAS) spectra of interfacial spiralin display a complex amide I band characteristic of a mixture of beta sheets and alpha helices, and an intense amide II band. Spectral simulations indicate a flat orientation for the beta sheets and a vertical orientation for the alpha helices with respect to the interface. The combination of tensiometric and PMIRRAS measurements show that, when spiroplasma lipids are used to form a monolayer at the air/water interface, spiralin is adsorbed under this monolayer and its antiparallel beta sheets are mainly parallel to the polar-head layer of the lipids without deep perturbation of the fatty acid chains organization. Based upon these results, we propose a 'carpet model' for spiralin organization at the spiroplasma cell surface. In this model, spiralin molecules anchored into the outer leaflet of the lipid bilayer by their N-terminal lipid moiety are composed of two colinear domains (instead of a single globular domain) situated at the lipid/water interface. Owing to the very high amount of spiralin in the membrane, such carpets would cover most if not all the lipids present in the outer leaflet of the bilayer.
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Affiliation(s)
- Sabine Castano
- LPCM-CRCM, UMR CNRS 5803, University Bordeaux I, Talence, France.
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35
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Nir-Paz R, Prévost MC, Nicolas P, Blanchard A, Wróblewski H. Susceptibilities of Mycoplasma fermentans and Mycoplasma hyorhinis to membrane-active peptides and enrofloxacin in human tissue cell cultures. Antimicrob Agents Chemother 2002; 46:1218-25. [PMID: 11959548 PMCID: PMC127185 DOI: 10.1128/aac.46.5.1218-1225.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycoplasmas, which are bacteria that are devoid of a cell wall and which belong to the class Mollicutes, are pathogenic for humans and animals and are frequent contaminants of tissue cell cultures. Although contamination of cultures with mycoplasma can easily be monitored with fluorescent dyes that stain DNA and/or with molecular probes, protection and decontamination of cultures remain serious challenges. In the present work, we investigated the susceptibilities of Mycoplasma fermentans and Mycoplasma hyorhinis to the membrane-active peptides alamethicin, dermaseptin B2, gramicidin S, and surfactin by growth inhibition and lethality assays. In the absence of serum, the four peptides killed mycoplasmas at minimal bactericidal concentrations that ranged from 12.5 to 100 microM, but in all cases the activities were decreased by the presence of serum. As a result, under standard culture conditions (10% serum) only alamethicin and gramicidin S were able to inhibit mycoplasma growth (MICs, 50 microM), while dermaseptin B2 and surfactin were ineffective. Furthermore, 8 days of treatment of HeLa cell cultures experimentally contaminated with either mycoplasma species with 70 microM enrofloxacin cured the cultures of infection, whereas treatment with alamethicin and gramicidin S alone was not reliable because the concentrations and treatment times required were toxic to the cells. However, combination of alamethicin or gramicidin S with 70 microM enrofloxacin allowed mycoplasma eradication after 30 min or 24 h of treatment, depending on the mycoplasma and peptide considered. HeLa cell cultures experimentally infected with mycoplasmas should prove to be a useful model for study of the antimycoplasma activities of antibiotics and membrane-active peptides under conditions close to those found in vivo.
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Affiliation(s)
- Ran Nir-Paz
- Unité d'Oncologie Virale, Institut Pasteur, Paris, France
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Shenkarev ZO, Balashova TA, Efremov RG, Yakimenko ZA, Ovchinnikova TV, Raap J, Arseniev AS. Spatial structure of zervamicin IIB bound to DPC micelles: implications for voltage-gating. Biophys J 2002; 82:762-71. [PMID: 11806918 PMCID: PMC1301885 DOI: 10.1016/s0006-3495(02)75438-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Zervamicin IIB is a 16-amino acid peptaibol that forms voltage-dependent ion channels with multilevel conductance states in planar lipid bilayers and vesicular systems. The spatial structure of zervamicin IIB bound to dodecylphosphocholine micelles was studied by nuclear magnetic resonance spectroscopy. The set of 20 structures obtained has a bent helical conformation with a mean backbone root mean square deviation value of approximately 0.2 A and resembles the structure in isotropic solvents (Balashova et al., 2000. NMR structure of the channel-former zervamicin IIB in isotropic solvents. FEBS Lett 466:333-336). The N-terminus represents an alpha-helix, whereas the C-terminal part has a mixed 3(10)/alpha(R) hydrogen-bond pattern. In the anisotropic micelle environment, the bending angle on Hyp10 (23 degrees) is smaller than that (47 degrees) in isotropic solvents. In the NOESY (Nuclear Overhauser Effect Spectroscopy) spectra, the characteristic attenuation of the peptide signals by 5- and 16-doxylstearate relaxation probes indicates a peripheral mode of the peptaibol binding to the micelle with the N-terminus immersed slightly deeper into micelle interior. Analysis of the surface hydrophobicity reveals that the zervamicin IIB helix is amphiphilic and well suited to formation of a tetrameric transmembrane bundle, according to the barrel-stave mechanism. The results are discussed in a context of voltage-driven peptaibol insertion into membrane.
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Affiliation(s)
- Z O Shenkarev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
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Dé E, Chaloin L, Heitz A, Méry J, Molle G, Heitz F. Conformation and ion channel properties of a five-helix Bundle protein. J Pept Sci 2001; 7:41-9. [PMID: 11245204 DOI: 10.1002/psc.293] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The primary amphipathic peptide Ac-Met-Gly-Leu-Gly-Leu-Trp-Leu-Leu-Val-Leu10-Ala-Ala-Ala-Leu-Gln-Gly-Ala-Lys-Lys-Lys20-Arg-Lys-Val-NH-CH2-CH2-SH called SPM was able to induce formation of ion channels into planar lipid bilayers with main conductance values of 75 and 950 pS in 1 M KCl. The 75 pS value can be attributed to an aggregate composed of five monomers since the corresponding five-unit bundle (5-SPM) also presented a 70 pS channels under the same conditions. The upper 950 pS level would be generated by a hexameric aggregate. Ion channels induced by both SPM and its pentameric bundle are slightly cation selective but not voltage-dependent. The structural studies showed that the SPM and 5-SPM possess mainly an alpha-helical structure (approximately 40%) and are strongly embedded in the bilayer. This behaviour and the strong hydrophobic interactions occurring between helices in the bundle induce a strong stabilization of 5-SPM in the bilayer and would be responsible for the stepwise current fluctuations observed during the incorporation of 5-SPM into the membrane.
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Affiliation(s)
- E Dé
- UMR 6522 CNRS, IFRMP 23, Faculté des Sciences, Mont-Saint-Aignan, France
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38
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Amiche M, Seon AA, Wroblewski H, Nicolas P. Isolation of dermatoxin from frog skin, an antibacterial peptide encoded by a novel member of the dermaseptin genes family. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:4583-92. [PMID: 10880984 DOI: 10.1046/j.1432-1327.2000.01514.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A 32-residue peptide, named dermatoxin, has been extracted from the skin of a single specimen of the tree frog Phyllomedusa bicolor, and purified to homogeneity using a four-step protocol. Mass spectral analysis and sequencing of the purified peptide, as well as chemical synthesis and cDNA analysis were consistent with the structure: SLGSFLKGVGTTLASVGKVVSDQF GKLLQAGQ. This peptide proved to be bactericidal towards mollicutes (wall-less eubacteria) and Gram-positive eubacteria, and also, though to a lesser extent, towards Gram-negative eubacteria. Measurement of the bacterial membrane potential revealed that the plasma membrane is the primary target of dermatoxin. Observation of bacterial cells using reflected light fluorescence microscopy after DNA-staining was consistent with a mechanism of cell killing based upon the alteration of membrane permeability rather than membrane solubilization, very likely by forming ion-conducting channels through the plasma membrane. CD spectroscopy and secondary structure predictions indicated that dermatoxin assumes an amphipathic alpha-helical conformation in low polarity media which mimic the lipophilicity of the membrane of target microorganisms. PCR analysis coupled with cDNA cloning and sequencing revealed that dermatoxin is expressed in the skin, the intestine and the brain. Preprodermatoxin from the brain and the intestine have the same sequence as the skin preproform except for two amino-acid substitutions in the preproregion of the brain precursor. The dermatoxin precursor displayed the characteristic features of preprodermaseptins, a family of peptide precursors found in the skin of Phyllomedusa ssp. Precursors of this family have a common N-terminal preproregion followed by markedly different C-terminal domains that give rise to 19-34-residue peptide antibiotics named dermaseptins B and phylloxin, and to the D-amino-acid-containing opioid heptapeptides dermorphins and deltorphins. Because the structures and cidal mechanisms of dermatoxin, dermaseptins B and phylloxin are very different, dermatoxin extends the repertoire of structurally and functionally diverse peptides derived from the rapidly evolving C-terminal domains of precursors of the dermaseptins family.
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Affiliation(s)
- M Amiche
- Laboratoire de Bioactivation des Peptides, Institut Jacques Monod, Paris, France
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