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Sani MA, Rajput S, Keizer DW, Separovic F. NMR techniques for investigating antimicrobial peptides in model membranes and bacterial cells. Methods 2024; 224:10-20. [PMID: 38295893 DOI: 10.1016/j.ymeth.2024.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/07/2024] [Accepted: 01/08/2024] [Indexed: 02/05/2024] Open
Abstract
AMPs are short, mainly cationic membrane-active peptides found in all living organism. They perform diverse roles including signaling and acting as a line of defense against bacterial infections. AMPs have been extensively investigated as templates to facilitate the development of novel antimicrobial therapeutics. Understanding the interplay between these membrane-active peptides and the lipid membranes is considered to be a significant step in elucidating the specific mechanism of action of AMPs against prokaryotic and eukaryotic cells to aid the development of new therapeutics. In this review, we have provided a brief overview of various NMR techniques commonly used for studying AMP structure and AMP-membrane interactions in model membranes and whole cells.
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Affiliation(s)
- Marc-Antoine Sani
- Bio21 Institute, University of Melbourne, Melbourne, VIC 3010, Australia.
| | - Sunnia Rajput
- Bio21 Institute, University of Melbourne, Melbourne, VIC 3010, Australia
| | - David W Keizer
- Bio21 Institute, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Frances Separovic
- Bio21 Institute, University of Melbourne, Melbourne, VIC 3010, Australia; School of Chemistry, University of Melbourne, Melbourne, VIC 3010, Australia
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Khavani M, Mehranfar A, Mofrad MRK. Antimicrobial peptide interactions with bacterial cell membranes. J Biomol Struct Dyn 2024:1-14. [PMID: 38263741 DOI: 10.1080/07391102.2024.2304683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 01/06/2024] [Indexed: 01/25/2024]
Abstract
Antimicrobial peptides (AMPs) are potential alternatives for common antibiotics because of their greater activity and efficiency against a broad range of viruses, bacteria, fungi, and parasites. In this project, two antimicrobial peptides including magainin 2 and protegrin 1 with α-helix and β-sheet secondary structures were selected to investigate their interactions with different lipid bilayers such as 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoserine (POPS), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG), and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), POPC/POPG (7:3), POPC/POPS (7:3), POPG/POPE(1:3), and POPG/POPE(3:1). The obtained structures of the AMPs illustrated that protegrin 1 cannot maintain its secondary structure in the solution phase in contrast to magainin 2. The head groups of the lipid units play a key role in the stability of the lipid bilayers. The head parts of the lipid membranes by increasing the internal H-bond contribute to membrane compactness. The POPG and POPS units inside the POPC/POPG and POPC/POPS membranes increase the order of the POPC units. The cationic residues of the AMPs form remarkable electrostatic interactions with the negatively charged membrane surfaces, which play a key role in the stabilization process of the peptide secondary structures. The Arg residues of protegrin 1 and the Gly1, Lys4, Lys10, Lys11, Lys14, and Glu19 of the magainin 2 have the most important roles in the complexation process. The values of Gibbs binding energies (ΔG) indicate that the complexation process between AMPs and different bacterial membranes is favorable from the thermodynamic viewpoint and AMPs could form stable complexes with the lipid bilayers. As a result of ΔG values, protegrin 1 forms a more stable complex with POPG/POPE(3:1), while the α-helix has more affinity to the POPG/POPE(1:3) bacterial membranes. Therefore, it can be considered that β-sheet and α-helix AMPs are more effective against gram-positive and gram-negative bacteria, respectively. The results of this study can provide useful details about the antimicrobial peptide interactions with the bacterial cell, which can be employed for designing new antimicrobial materials with greater efficiency.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Mohammad Khavani
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, California, USA
| | - Aliyeh Mehranfar
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, California, USA
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, California, USA
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Talandashti R, Mehrnejad F, Rostamipour K, Doustdar F, Lavasanifar A. Molecular Insights into Pore Formation Mechanism, Membrane Perturbation, and Water Permeation by the Antimicrobial Peptide Pleurocidin: A Combined All-Atom and Coarse-Grained Molecular Dynamics Simulation Study. J Phys Chem B 2021; 125:7163-7176. [PMID: 34171196 DOI: 10.1021/acs.jpcb.1c01954] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The antimicrobial peptide (AMP) pleurocidin has a broad antimicrobial activity against Gram-negative and Gram-positive bacteria by perturbation and permeabilizing their membranes; however, understanding the mechanism of action of pleurocidin, a promising AMP for replacing current antibiotic agents, has tremendous importance for future applications. Hence, we applied all-atom (AA) and coarse-grained (CG) molecular dynamics (MD) simulations to provide molecular-level insights into the pore-forming process. The early stages of pore formation were examined by 500 ns AA simulations. The results demonstrated that pleurocidin has the ability to create a pore with two peptides through which water molecules can flow. However, the results of the 25 μs CG simulations indicate that the final pore will be created by accumulation of more than two peptides. The results show that after 2.5 μs of simulations, peptides will aggregate and create a channel-like pore across the membrane. Pleurocidin can construct a more efficient and stable pore in the anionic membranes than in the zwitterionic membranes. Moreover, the structure amphipathicity, polarity, and basic residues play crucial roles in the pore formation and flow of water molecules across the lipid bilayers. In general, the findings revealed that based on the lipid compositions of the membranes, pleurocidin could act by forming either toroidal or disordered toroidal pores with different peptide arrangements.
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Affiliation(s)
- Reza Talandashti
- Infectious Diseases and Tropical Medicine Research Center, Shahid Beheshti University of Medical Sciences, P. O. Box: 1985717443 Tehran, Iran.,Department of Life Sciences Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran 14395-1561, Iran
| | - Faramarz Mehrnejad
- Department of Life Sciences Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran 14395-1561, Iran
| | - Kiana Rostamipour
- Department of Life Sciences Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran 14395-1561, Iran
| | - Farahnoosh Doustdar
- Department of Life Sciences Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran 14395-1561, Iran.,Department of Microbiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran 19839-63113, Iran
| | - Afsaneh Lavasanifar
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
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Zhu S, Li W, O'Brien-Simpson N, Separovic F, Sani MA. C-terminus amidation influences biological activity and membrane interaction of maculatin 1.1. Amino Acids 2021; 53:769-777. [PMID: 33891157 DOI: 10.1007/s00726-021-02983-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/16/2021] [Indexed: 11/24/2022]
Abstract
Cationic antimicrobial peptides have been investigated for their potential use in combating infections by targeting the cell membrane of microbes. Their unique chemical structure has been investigated to understand their mode of action and optimize their dose-response by rationale design. One common feature among cationic AMPs is an amidated C-terminus that provides greater stability against in vivo degradation. This chemical modification also likely modulates the interaction with the cell membrane of bacteria yet few studies have been performed comparing the effect of the capping groups. We used maculatin 1.1 (Mac1) to assess the role of the capping groups in modulating the peptide bacterial efficiency, stability and interactions with lipid membranes. Circular dichroism results showed that C-terminus amidation maintains the structural stability of the peptide (α-helix) in contact with micelles. Dye leakage experiments revealed that amidation of the C-terminus resulted in higher membrane disruptive ability while bacteria and cell viability assays revealed that the amidated form displayed higher antibacterial ability and cytotoxicity compared to the acidic form of Mac1. Furthermore, 31P and 2H solid-state NMR showed that C-terminus amidation played a greater role in disturbance of the phospholipid headgroup but had little effect on the lipid tails. This study paves the way to better understand how membrane-active AMPs act in live bacteria.
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Affiliation(s)
- Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Wenyi Li
- Melbourne Dental School and Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Neil O'Brien-Simpson
- Melbourne Dental School and Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia.
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Sheard DE, O’Brien-Simpson NM, Wade JD, Separovic F. Combating bacterial resistance by combination of antibiotics with antimicrobial peptides. PURE APPL CHEM 2019. [DOI: 10.1515/pac-2018-0707] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
The overuse of antibiotics in the healthcare and agricultural industries has led to the worldwide spread of bacterial resistance. The recent emergence of multidrug resistant (MDR) bacteria has resulted in a call for the development of novel strategies to address this global issue. Research on a diverse range of antimicrobial peptides (AMPs) has shown promising activity against several resistant strains. Increased understanding of the mode of action of AMPs has shown similarity and complementarity to conventional antibiotics and the combination of both has led to synergistic effects in some cases. Combination therapy has been widely used to combat MDR bacterial infections and the recent focus on their application with AMPs may allow antibiotics to be effective against resistant bacterial strains. By conjugation of an antibiotic onto an AMP, a compound may be produced with possibly greater activity and with reduced side-effects and toxicity. The AMP in these conjugates may also act as a unique adjuvant for the antibiotic by disrupting the resistance mechanisms used by bacteria thus allowing the antibiotic to once again be effective. This mini-review outlines some of the current and past work in combining AMPs with conventional antibiotics as strategies to address bacterial resistance.
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Affiliation(s)
- Dean E. Sheard
- School of Chemistry, Bio21 Institute, University of Melbourne , Melbourne, VIC 3010 , Australia
| | - Neil M. O’Brien-Simpson
- Centre of Oral Health Research, Melbourne Dental School, University of Melbourne , Melbourne, VIC 3010 , Australia
| | - John D. Wade
- School of Chemistry, Bio21 Institute, University of Melbourne , Melbourne, VIC 3010 , Australia
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne , Melbourne, VIC 3010 , Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne , Melbourne, VIC 3010 , Australia
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Lee TH, Sani MA, Overall S, Separovic F, Aguilar MI. Effect of phosphatidylcholine bilayer thickness and molecular order on the binding of the antimicrobial peptide maculatin 1.1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:300-309. [DOI: 10.1016/j.bbamem.2017.10.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 09/18/2017] [Accepted: 10/08/2017] [Indexed: 01/01/2023]
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Charged Antimicrobial Peptides Can Translocate across Membranes without Forming Channel-like Pores. Biophys J 2017; 113:73-81. [PMID: 28700927 DOI: 10.1016/j.bpj.2017.04.056] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/18/2017] [Accepted: 04/26/2017] [Indexed: 01/08/2023] Open
Abstract
How can highly charged, cationic antimicrobial peptides (AMPs) translocate across hydrophobic lipid bilayers despite the prohibitive energetic penalty to do so? A common explanation has been the formation of peptide-lined channels. However, for most AMPs, no structures of membrane pores have been found despite clear evidence of membrane leakage and antimicrobial activity. The study here suggests an alternative and simple reason: for the AMP PGLa from Xenopus laevis (charge +5), such pores are not needed to explain both leakage and peptide translocation. Elevated-temperature multimicrosecond equilibrium simulations at all-atomistic level reveal that peptides spontaneously translocate across the membrane individually on a timescale of tens of microseconds, without forming pores. Both surface-bound peptides and lipids assist in the one-by-one translocation of the charged side chains. Single peptides can remain in a transmembrane orientation for many microseconds, snorkeling some charged residues to one interface and some to the opposite, but without inducing a water channel. Instead of stable pores, short-lived water bridges occur when two or three peptides connect at their termini, allowing both ion translocation and lipid flip-flop via a brushlike mechanism usually involving the C terminus of one peptide. The results here suggest that for some specific antimicrobial and other membrane active peptides, pore formation may not have to be invoked at all to explain peptide translocation and membrane permeabilization, which may explain why no channel structures for them have been determined experimentally.
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Comparison of reversible membrane destabilisation induced by antimicrobial peptides derived from Australian frogs. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2205-15. [PMID: 24593995 DOI: 10.1016/j.bbamem.2014.02.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 01/21/2014] [Accepted: 02/21/2014] [Indexed: 12/28/2022]
Abstract
The membrane destabilising properties of the antimicrobial peptides (AMP) aurein 1.2, citropin 1.1, maculatin 1.1 and caerin 1.1, have been studied by dual polarisation interferometry (DPI). The overall process of peptide induced membrane destabilisation was examined by the changes in bilayer order as a function of membrane-bound peptide mass per unit area and revealed three different modes of action. Aurein 1.2 was the only peptide that significantly destabilised the neutral membrane (DMPC), while all four peptides induced destabilisation of the negatively charged membrane (DMPC/DMPG). On DMPC, citropin 1.1, maculatin 1.1 and caerin 1.1 bound irreversibly at low concentrations but caused a reversible drop in the bilayer order. In contrast to DMPC/DMPG, these three peptides caused a mass drop at the higher concentrations, which may correspond to insertion and bilayer expansion. The critical level of bound peptide necessary to induce membrane destabilisation (peptide:lipid ratio) was determined and correlated with peptide structure. As the most lytic peptide, aurein 1.2 adsorbed strongly prior to dissolution of the bilayer. In contrast, the binding of citropin 1.1, maculatin 1.1 and caerin 1.1 needed to reach a critical level prior to insertion into the membrane and incremental expansion and disruption. Our results demonstrate that sequential events can be monitored in real-time under fluidic conditions to elucidate the complex molecular mechanism of AMP action. In particular, the analysis of birefringence in real time allows the description of a detailed mechanistic model of the impact of peptides on the membrane bilayer order. 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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Caillon L, Killian JA, Lequin O, Khemtémourian L. Biophysical investigation of the membrane-disrupting mechanism of the antimicrobial and amyloid-like peptide dermaseptin S9. PLoS One 2013; 8:e75528. [PMID: 24146759 PMCID: PMC3795727 DOI: 10.1371/journal.pone.0075528] [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: 05/31/2013] [Accepted: 08/14/2013] [Indexed: 12/16/2022] Open
Abstract
Dermaseptin S9 (Drs S9) is an atypical cationic antimicrobial peptide with a long hydrophobic core and with a propensity to form amyloid-like fibrils. Here we investigated its membrane interaction using a variety of biophysical techniques. Rather surprisingly, we found that Drs S9 induces efficient permeabilisation in zwitterionic phosphatidylcholine (PC) vesicles, but not in anionic phosphatidylglycerol (PG) vesicles. We also found that the peptide inserts more efficiently in PC than in PG monolayers. Therefore, electrostatic interactions between the cationic Drs S9 and anionic membranes cannot explain the selectivity of the peptide towards bacterial membranes. CD spectroscopy, electron microscopy and ThT fluorescence experiments showed that the peptide adopts slightly more β-sheet and has a higher tendency to form amyloid-like fibrils in the presence of PC membranes as compared to PG membranes. Thus, induction of leakage may be related to peptide aggregation. The use of a pre-incorporation protocol to reduce peptide/peptide interactions characteristic of aggregates in solution resulted in more α-helix formation and a more pronounced effect on the cooperativity of the gel-fluid lipid phase transition in all lipid systems tested. Calorimetric data together with 2H- and 31P-NMR experiments indicated that the peptide has a significant impact on the dynamic organization of lipid bilayers, albeit slightly less for zwitterionic than for anionic membranes. Taken together, our data suggest that in particular in membranes of zwitterionic lipids the peptide binds in an aggregated state resulting in membrane leakage. We propose that also the antimicrobial activity of Drs S9 may be a result of binding of the peptide in an aggregated state, but that specific binding and aggregation to bacterial membranes is regulated not by anionic lipids but by as yet unknown factors.
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Affiliation(s)
- Lucie Caillon
- UPMC Univ Paris 06, UMR 7203 CNRS-UPMC-ENS, Laboratoire des Biomolécules, Paris, France
| | - J. Antoinette Killian
- Research Group Membrane Biochemistry & Biophysics, Bijvoet Center and Institute of Biomembranes, Utrecht University, Utrecht, The Netherlands
| | - Olivier Lequin
- UPMC Univ Paris 06, UMR 7203 CNRS-UPMC-ENS, Laboratoire des Biomolécules, Paris, France
- * E-mail: (LK); (OL)
| | - Lucie Khemtémourian
- UPMC Univ Paris 06, UMR 7203 CNRS-UPMC-ENS, Laboratoire des Biomolécules, Paris, France
- * E-mail: (LK); (OL)
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Fernandez DI, Sani MA, Miles AJ, Wallace B, Separovic F. Membrane defects enhance the interaction of antimicrobial peptides, aurein 1.2 versus caerin 1.1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1863-72. [DOI: 10.1016/j.bbamem.2013.03.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Revised: 03/05/2013] [Accepted: 03/08/2013] [Indexed: 10/27/2022]
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Fernandez D, Lee TH, Sani MA, Aguilar MI, Separovic F. Proline facilitates membrane insertion of the antimicrobial peptide maculatin 1.1 via surface indentation and subsequent lipid disordering. Biophys J 2013; 104:1495-507. [PMID: 23561526 PMCID: PMC3617439 DOI: 10.1016/j.bpj.2013.01.059] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 01/23/2013] [Accepted: 01/28/2013] [Indexed: 01/08/2023] Open
Abstract
The role of proline in the disruption of membrane bilayer structure upon antimicrobial peptide (AMP) binding was studied. Specifically, (31)P and (2)H solid-state NMR and dual polarization interferometry (DPI) were used to analyze the membrane interactions of three AMPs: maculatin 1.1 and two analogs in which Pro-15 is replaced by Gly and Ala. For NMR, deuterated dimyristoylphosphatidylcholine (d54-DMPC) and d54-DMPC/dimyristoylphosphatidylglycerol (DMPG) were used to mimic eukaryotic and prokaryotic membranes, respectively. In fluid-phase DMPC bilayer systems, the peptides interacted primarily with the bilayer surface, with the native peptide having the strongest interaction. In the mixed DMPC/DMPG bilayers, maculatin 1.1 induced DMPG phase separation, whereas the analogs promoted the formation of isotropic and lipid-enriched phases with an enhanced effect relative to the neutral DMPC bilayers. In gel-phase DMPC vesicles, the native peptide disrupted the bilayer via a surface mechanism, and the effect of the analogs was similar to that observed in the fluid phase. Real-time changes in bilayer order were examined via DPI, with changes in bilayer birefringence analyzed as a function of the peptide mass bound to the bilayer. Although all three peptides decreased the bilayer order as a function of bound concentration, maculatin 1.1 caused the largest change in bilayer structure. The NMR data indicate that maculatin 1.1 binds predominantly at the surface regions of the bilayer, and both NMR and DPI results indicate that this binding leads to a drop in bilayer order. Overall, the results demonstrate that the proline at residue 15 plays a central role in the membrane interaction of maculatin 1.1 by inducing a significant change in membrane order and affecting the ability of the bilayer to recover from structural changes induced by the binding and insertion of the peptide.
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Affiliation(s)
- David I. Fernandez
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria, Australia
| | - Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria, Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria, Australia
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Grieco P, Carotenuto A, Auriemma L, Saviello MR, Campiglia P, Gomez-Monterrey IM, Marcellini L, Luca V, Barra D, Novellino E, Mangoni ML. The effect of d-amino acid substitution on the selectivity of temporin L towards target cells: Identification of a potent anti-Candida peptide. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:652-60. [DOI: 10.1016/j.bbamem.2012.08.027] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Revised: 08/27/2012] [Accepted: 08/30/2012] [Indexed: 12/27/2022]
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Fernandez DI, Le Brun AP, Whitwell TC, Sani MA, James M, Separovic F. The antimicrobial peptide aurein 1.2 disrupts model membranes via the carpet mechanism. Phys Chem Chem Phys 2012; 14:15739-51. [PMID: 23093307 DOI: 10.1039/c2cp43099a] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The membrane interactions of the antimicrobial peptide aurein 1.2 were studied using a range of biophysical techniques to determine the location and the mechanism of action in DMPC (dimyristoylphosphatidylcholine) and DMPC/DMPG (dimyristoylphosphatidylglycerol) model membranes that mimic characteristics of eukaryotic and prokaryotic membranes, respectively. Neutron reflectometry and solid-state NMR revealed subtle changes in membrane structure caused by the peptide. Quartz crystal microbalance with dissipation, vesicle dye leakage and atomic force microscopy measurements were used to investigate the global mode of peptide interaction. Aurein 1.2 displayed an enhanced interaction with the anionic DMPC/DMPG membrane while exhibiting primarily a surface interaction with both types of model membranes, which led to bilayer disruption and membrane lysis. The antimicrobial peptide interaction is consistent with the carpet mechanism for aurein 1.2 with discrete structural changes depending on the type of phospholipid membrane.
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Affiliation(s)
- David I Fernandez
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC 3010, Australia
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Bowie JH, Separovic F, Tyler MJ. Host-defense peptides of Australian anurans. Part 2. Structure, activity, mechanism of action, and evolutionary significance. Peptides 2012; 37:174-88. [PMID: 22771617 DOI: 10.1016/j.peptides.2012.06.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 06/26/2012] [Accepted: 06/26/2012] [Indexed: 01/01/2023]
Abstract
A previous review summarized research prior to 2004 carried out on the bioactive host-defense peptides contained in the skin secretions of Australian anurans (frogs and toads). This review covers the extension of that research from 2004 to 2012, and includes membrane-active peptides (including antibacterial, anticancer, antifungal and antiviral peptides) together with the mechanisms by which these peptides interact with model membranes, peptides that may be classified as "neuropeptides" (including smooth muscle active peptides, opioids and immunomodulators) and peptides which inhibit the formation of nitric oxide from neuronal nitric oxide synthase. The review discusses the outcome of cDNA sequencing of signal-spacer-active peptides from an evolutionary viewpoint, and also lists those peptides for which activities have not been found to this time.
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Affiliation(s)
- John H Bowie
- Department of Chemistry, School of Chemistry and Physics, The University of Adelaide, South Australia 5005, Australia.
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Sanderson JM. Resolving the kinetics of lipid, protein and peptide diffusion in membranes. Mol Membr Biol 2012; 29:118-43. [DOI: 10.3109/09687688.2012.678018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Structural effects of the antimicrobial peptide maculatin 1.1 on supported lipid bilayers. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 42:47-59. [DOI: 10.1007/s00249-012-0796-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 01/25/2012] [Accepted: 02/02/2012] [Indexed: 01/23/2023]
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Weber DK, Gehman JD, Separovic F, Sani MA. Copper Modulation of Amyloid Beta 42 Interactions with Model Membranes. Aust J Chem 2012. [DOI: 10.1071/ch12015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Growing evidence supports that interactions of the amyloid-β peptide Aβ(1–42) with neuronal cell membranes and copper are involved in Alzheimer’s disease pathogenesis. We report using solid-state NMR that the peptide significantly perturbed the phosphate and upper acyl chain region of bilayers comprising brain total lipid extract to cause domain segregation. Deep headgroup perturbations were also realized for palmitoyloleoylphospatidylcholine–cholesterol model systems; however, incorporating 10 % palmitoyloleoylphosphatidylserine or the ganglioside GM1 resulted in a more peripheral interaction. Cu2+ at a 1 : 7 molar ratio to peptide caused deeper penetration into model systems, but partially attenuated interactions with brain total lipid extract. Thioflavin T assay showed that bilayers affected amyloid formation in a mode dependant on lipid content, and was further modulated by addition of Cu2+. Our data support that ternary interactions between Cu2+, lipids and Aβ(1–42) may have significance in Alzheimer’s disease, and challenge the validity of model bilayers as substitutes for natural systems.
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