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Ouyang J, Sheng Y, Wang W. Recent Advances of Studies on Cell-Penetrating Peptides Based on Molecular Dynamics Simulations. Cells 2022; 11:cells11244016. [PMID: 36552778 PMCID: PMC9776715 DOI: 10.3390/cells11244016] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/09/2022] [Accepted: 12/10/2022] [Indexed: 12/14/2022] Open
Abstract
With the ability to transport cargo molecules across cell membranes with low toxicity, cell-penetrating peptides (CPPs) have become promising candidates for next generation peptide-based drug delivery vectors. Over the past three decades since the first CPP was discovered, a great deal of work has been done on the cellular uptake mechanisms and the applications for the delivery of therapeutic molecules, and significant advances have been made. But so far, we still do not have a precise and unified understanding of the structure-activity relationship of the CPPs. Molecular dynamics (MD) simulations provide a method to reveal peptide-membrane interactions at the atomistic level and have become an effective complement to experiments. In this paper, we review the progress of the MD simulations on CPP-membrane interactions, including the computational methods and technical improvements in the MD simulations, the research achievements in the CPP internalization mechanism, CPP decoration and coupling, and the peptide-induced membrane reactions during the penetration process, as well as the comparison of simulated and experimental results.
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Affiliation(s)
- Jun Ouyang
- School of Public Courses, Bengbu Medical College, Bengbu 233030, China
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing 210093, China
| | - Yuebiao Sheng
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing 210093, China
- High Performance Computing Center, Nanjing University, Nanjing 210093, China
- Correspondence: (Y.S.); (W.W.)
| | - Wei Wang
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing 210093, China
- Correspondence: (Y.S.); (W.W.)
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2
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Perez-Rodriguez A, Eraso E, Quindós G, Mateo E. Antimicrobial Peptides with Anti-Candida Activity. Int J Mol Sci 2022; 23:ijms23169264. [PMID: 36012523 PMCID: PMC9409312 DOI: 10.3390/ijms23169264] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/10/2022] [Accepted: 08/13/2022] [Indexed: 02/06/2023] Open
Abstract
Mycoses are accountable for millions of infections yearly worldwide. Invasive candidiasis is the most usual, presenting a high morbidity and mortality. Candida albicans remains the prevalent etiologic agent, but the incidence of other species such as Candida parapsilosis, Candida glabrata and Candida auris keeps increasing. These pathogens frequently show a reduced susceptibility to commonly used antifungal drugs, including polyenes, triazoles and echinocandins, and the incidence of emerging multi-drug-resistant strains of these species continues to increase. Therefore, the need to search for new molecules that target these pathogenic species in a different manner is now more urgent than ever. Nature is an almost endless source of interesting new molecules that could meet this need. Among these molecules, antimicrobial peptides, present in different sources in nature, possess some advantages over conventional antifungal agents, even with their own drawbacks, and are considered as a promising pharmacological option against a wide range of microbial infections. In this review, we describe 20 antimicrobial peptides from different origins that possess an activity against Candida.
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3
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ELSALEM L, KHASAWNEH A, AL SHEBOUL S. WLBU2 Antimicrobial Peptide as a Potential Therapeutic for Treatment of Resistant Bacterial Infections. Turk J Pharm Sci 2022; 19:110-116. [DOI: 10.4274/tjps.galenos.2020.43078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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4
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Kratochvil HT, Newberry RW, Mensa B, Mravic M, DeGrado WF. Spiers Memorial Lecture: Analysis and de novo design of membrane-interactive peptides. Faraday Discuss 2021; 232:9-48. [PMID: 34693965 PMCID: PMC8979563 DOI: 10.1039/d1fd00061f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Membrane-peptide interactions play critical roles in many cellular and organismic functions, including protection from infection, remodeling of membranes, signaling, and ion transport. Peptides interact with membranes in a variety of ways: some associate with membrane surfaces in either intrinsically disordered conformations or well-defined secondary structures. Peptides with sufficient hydrophobicity can also insert vertically as transmembrane monomers, and many associate further into membrane-spanning helical bundles. Indeed, some peptides progress through each of these stages in the process of forming oligomeric bundles. In each case, the structure of the peptide and the membrane represent a delicate balance between peptide-membrane and peptide-peptide interactions. We will review this literature from the perspective of several biologically important systems, including antimicrobial peptides and their mimics, α-synuclein, receptor tyrosine kinases, and ion channels. We also discuss the use of de novo design to construct models to test our understanding of the underlying principles and to provide useful leads for pharmaceutical intervention of diseases.
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Affiliation(s)
- Huong T Kratochvil
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
| | - Robert W Newberry
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
| | - Bruk Mensa
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
| | - Marco Mravic
- Department of Integrative Structural and Computational Biology, Scripps Research Institute, La Jolla, CA 92037, USA
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
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5
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Osella S, Knippenberg S. The influence of lipid membranes on fluorescent probes' optical properties. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183494. [PMID: 33129783 DOI: 10.1016/j.bbamem.2020.183494] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND Organic fluorophores embedded in lipid bilayers can nowadays be described by a multiscale computational approach. Combining different length and time scales, a full characterization of the probe localization and optical properties led to novel insight into the effect of the environments. SCOPE OF REVIEW Following an introduction on computational advancements, three relevant probes are reviewed that delineate how a multiscale approach can lead to novel insight into the probes' (non) linear optical properties. Attention is paid to the quality of the theoretical description of the optical techniques. MAJOR CONCLUSIONS Computation can assess a priori novel probes' optical properties and guide the analysis and interpretation of experimental data in novel studies. The properties can be used to gain information on the phase and condition of the surrounding biological environment. GENERAL SIGNIFICANCE Computation showed that a canonical view on some of the probes should be revisited and adapted.
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Affiliation(s)
- Silvio Osella
- Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland.
| | - Stefan Knippenberg
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic; Department of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden; Theoretical Physics, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium.
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6
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Downing R, Volpe Bossa G, May S. Saddle-curvature instability of lipid bilayer induced by amphipathic peptides: a molecular model. SOFT MATTER 2020; 16:5032-5043. [PMID: 32452495 DOI: 10.1039/d0sm00499e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Amphipathic peptides that partition into lipid bilayers affect the curvature elastic properties of their host. Some of these peptides are able to shift the Gaussian modulus to positive values, thus triggering an instability with respect to the formation of saddle curvatures. To characterize the generic aspects of the underlying mechanism, we employ a molecular lipid model that accounts for the interfacial tension between the polar and apolar regions of the membrane, for interactions between the lipid headgroups, and for the energy to stretch or compress the hydrocarbon chains. Peptides are modeled as cylinders that partition into the host membrane in a parallel orientation where they diminish the space available to the lipid headgroups and chains. The penetration depth into the membrane is determined by the angular size of the peptide's hydrophilic region. We demonstrate that only peptides with a small angular size of their hydrophilic region have an intrinsic tendency to render the Gaussian modulus more positive, and we identify conditions at which the Gaussian modulus adopts a positive sign upon increasing the peptide concentration. Our model allows us to also incorporate electrostatic interactions between cationic peptides and anionic lipids on the level of the linear Debye-Hückel model. We show that electrostatic interactions tend to shift the Gaussian modulus toward more positive values. Steric and electrostatic lipid-peptide interactions jointly decrease the effective interaction strength in the headgroup region of the host membrane thus suggesting a generic mechanisms of how certain amphipathic peptides are able to induce the formation of saddle curvatures.
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Affiliation(s)
- Rachel Downing
- Department of Physics, North Dakota State University, Fargo North Dakota 58108-6050, USA
| | - Guilherme Volpe Bossa
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil.
| | - Sylvio May
- Department of Physics, North Dakota State University, Fargo North Dakota 58108-6050, USA
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7
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Nangia S, Boyd KJ, May ER. Molecular dynamics study of membrane permeabilization by wild-type and mutant lytic peptides from the non-enveloped Flock House virus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183102. [PMID: 31678020 DOI: 10.1016/j.bbamem.2019.183102] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/16/2019] [Accepted: 10/14/2019] [Indexed: 12/19/2022]
Abstract
Flock House virus (FHV) serves as a model system for understanding infection mechanisms utilized by non-enveloped viruses to transport across cellular membranes. During the infection cycle of FHV, a fundamental stage involves disruption of the endosomal membrane by membrane active peptides, following externalization of the peptides from the capsid interior. The FHV lytic agents are the 44 C-terminal amino acids residues of the capsid protein, which are auto-catalytically cleaved during the capsid maturation process. The cleaved peptides are termed γ peptides. In this study, we perform multi-scale molecular dynamics simulations including 40 μs all-atom molecular dynamics simulations to study the behavior of pre-inserted transmembrane lytic peptides at a high concentration in a neutral membrane. We study the dynamical organization among peptides to form oligomeric bundles in four systems including the wild-type γ peptide and three mutant forms; namely, a truncation mutant in which the 23 C-terminal residues are deleted (γ1), a construct where the 8 C-terminal residues of γ are fused to γ1 (Δ385-399 γ) and a single-point mutant (F402A γ), all of which have been experimentally shown to drastically affect infectivity and lytic activity compared to the wild-type γ. Our results shed light on the actions of varied forms of the FHV lytic peptide including membrane insertion, trans-membrane stability, peptide oligomerization, water permeation activity and dynamic pore formation. Findings from this study provide detailed structural information and rationale for the differences in lytic activity among variants of FHV γ.
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Affiliation(s)
- Shivangi Nangia
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, United States of America
| | - Kevin J Boyd
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, United States of America
| | - Eric R May
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, United States of America.
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8
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Swedan S, Shubair Z, Almaaytah A. Synergism of cationic antimicrobial peptide WLBU2 with antibacterial agents against biofilms of multi-drug resistant Acinetobacter baumannii and Klebsiella pneumoniae. Infect Drug Resist 2019; 12:2019-2030. [PMID: 31372010 PMCID: PMC6636432 DOI: 10.2147/idr.s215084] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 06/23/2019] [Indexed: 11/23/2022] Open
Abstract
Purpose The activity of the cationic antimicrobial peptide WLBU2 was evaluated against planktonic cells and biofilms of multi-drug resistant (MDR) Acinetobacter baumannii and Klebsiella pneumoniae, alone and in combination with classical antimicrobial agents. Methods Control American Type Culture Collection (ATCC) strains and MDR clinical isolates of A. baumannii and K. pneumoniae were utilized. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of WLBU2 alone and in combination with antimicrobials were determined by classical methods. The Calgary biofilm device was used to determine the minimum biofilm eradication concentration (MBEC). The MTT assay was used to determine the cytotoxicity of agents on eukaryotic cells. The electrophoretic mobility shift assay was used to evaluate the ability of WLBU2 to bind bacterial DNA. Results The WLBU2 MIC and MBC values were identical indicating bactericidal activity. The MIC/MBC values ranged from 1.5625 to 12.5 µM. At these concentrations, Vero cells and human skin fibroblasts were viable. The MBEC of WLBU2 ranged from 25 to 200 µM. A significant loss of eukaryotic cell viability was observed at the MBEC range. The combination of sub-inhibitory concentrations of WLBU2 with amoxicillin-clavulanate or ciprofloxacin for K. pneumoniae, and with tobramycin or imipenem for A. baumannii, demonstrated synergism, leading to a significant decrease in MIC and MBEC values for some isolates and ATCC strains. However, all combinations were associated with considerable loss in eukaryotic cells’ viability. WLBU2 did not demonstrate the ability to bind bacterial plasmid DNA. Conclusion WLBU2 in combination with antimicrobials holds promise in eradication of MDR pathogens.
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Affiliation(s)
- Samer Swedan
- Jordan University of Science and Technology, Department of Medical Laboratory Sciences, Irbid, Jordan
| | - Zaina Shubair
- Jordan University of Science and Technology, Department of Medical Laboratory Sciences, Irbid, Jordan
| | - Ammar Almaaytah
- Jordan University of Science and Technology, Department of Pharmaceutical Technology, Irbid, Jordan
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9
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Reid KA, Davis CM, Dyer RB, Kindt JT. Binding, folding and insertion of a β-hairpin peptide at a lipid bilayer surface: Influence of electrostatics and lipid tail packing. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:792-800. [PMID: 29291379 DOI: 10.1016/j.bbamem.2017.12.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 12/12/2017] [Accepted: 12/25/2017] [Indexed: 12/11/2022]
Abstract
Antimicrobial peptides (AMPs) act as host defenses against microbial pathogens. Here we investigate the interactions of SVS-1 (KVKVKVKVdPlPTKVKVKVK), an engineered AMP and anti-cancer β-hairpin peptide, with lipid bilayers using spectroscopic studies and atomistic molecular dynamics simulations. In agreement with literature reports, simulation and experiment show preferential binding of SVS-1 peptides to anionic over neutral bilayers. Fluorescence and circular dichroism studies of a Trp-substituted SVS-1 analogue indicate, however, that it will bind to a zwitterionic DPPC bilayer under high-curvature conditions and folds into a hairpin. In bilayers formed from a 1:1 mixture of DPPC and anionic DPPG lipids, curvature and lipid fluidity are also observed to promote deeper insertion of the fluorescent peptide. Simulations using the CHARMM C36m force field offer complementary insight into timescales and mechanisms of folding and insertion. SVS-1 simulated at an anionic mixed POPC/POPG bilayer folded into a hairpin over a microsecond, the final stage in folding coinciding with the establishment of contact between the peptide's valine sidechains and the lipid tails through a "flip and dip" mechanism. Partial, transient folding and superficial bilayer contact are seen in simulation of the peptide at a zwitterionic POPC bilayer. Only when external surface tension is applied does the peptide establish lasting contact with the POPC bilayer. Our findings reveal the influence of disruption to lipid headgroup packing (via curvature or surface tension) on the pathway of binding and insertion, highlighting the collaborative effort of electrostatic and hydrophobic interactions on interaction of SVS-1 with lipid bilayers.
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Affiliation(s)
- Keon A Reid
- Department of Chemistry, Emory University, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - Caitlin M Davis
- Department of Chemistry, Emory University, 201 Dowman Drive, Atlanta, GA 30322, United States; Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - R Brian Dyer
- Department of Chemistry, Emory University, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - James T Kindt
- Department of Chemistry, Emory University, 201 Dowman Drive, Atlanta, GA 30322, United States.
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10
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Dubovskii PV, Dubinnyi MA, Volynsky PE, Pustovalova YE, Konshina AG, Utkin YN, Arseniev AS, Efremov RG. Impact of membrane partitioning on the spatial structure of an S-type cobra cytotoxin. J Biomol Struct Dyn 2017; 36:3463-3478. [DOI: 10.1080/07391102.2017.1389662] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Peter V. Dubovskii
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya str., Moscow 117997, Russia
| | - Maxim A. Dubinnyi
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya str., Moscow 117997, Russia
| | - Pavel E. Volynsky
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya str., Moscow 117997, Russia
| | - Yulia E. Pustovalova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya str., Moscow 117997, Russia
| | - Anastasia G. Konshina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya str., Moscow 117997, Russia
| | - Yuri N. Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya str., Moscow 117997, Russia
| | - Alexander S. Arseniev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya str., Moscow 117997, Russia
- Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141700, Russia
| | - Roman G. Efremov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya str., Moscow 117997, Russia
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11
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Ulmschneider JP, Ulmschneider MB. Folding Simulations of the Transmembrane Helix of Virus Protein U in an Implicit Membrane Model. J Chem Theory Comput 2015; 3:2335-46. [PMID: 26636223 DOI: 10.1021/ct700103k] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vpu is an 81-amino-acid auxiliary membrane protein encoded by human immunodeficiency virus type 1 (HIV-1). One of its roles is to amplify viral release by self-assembling in homo-oligomers to form functional water-filled pores enabling the flux of ions across the membrane. Various NMR and CD studies have shown that the transmembrane domain of Vpu has a helical conformation. With a recently developed implicit membrane model and an efficient Monte Carlo (MC) algorithm using concerted backbone rotations, we simulate the folding of the transmembrane domain of Vpu at atomic resolution. The implicit membrane environment is based on the generalized Born theory and enables very long time scale events, such as folding to be observed using detailed all-atom representation of the protein. Such studies are currently computationally unfeasible with fully explicit lipid bilayer molecular dynamics simulations. The correct helical transmembrane structure of Vpu is predicted from extended conformations and remains stably inserted. Tilt and kink angles agree well with experimental estimates from NMR measurements. The experimentally observed change in tilt angle in membranes of varying hydrophobic width is accurately reproduced. The extensive simulation of a pentamer of the Vpu transmembrane domain in the implicit membrane gives results similar to the ones reported previously for fully explicit bilayer simulations.
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Affiliation(s)
- Jakob P Ulmschneider
- Department of Chemistry, University of Rome "La Sapienza", Rome, Italy, and Department of Biochemistry, University of Oxford, Oxford, U.K
| | - Martin B Ulmschneider
- Department of Chemistry, University of Rome "La Sapienza", Rome, Italy, and Department of Biochemistry, University of Oxford, Oxford, U.K
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12
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Han E, Lee H. Structural effects of tachyplesin I and its linear derivative on their aggregation and mobility in lipid bilayers. J Mol Graph Model 2015; 59:123-8. [DOI: 10.1016/j.jmgm.2015.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 04/09/2015] [Accepted: 04/17/2015] [Indexed: 10/23/2022]
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13
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Nguyen QNN, Lodewyk MW, Bezer S, Gagné MR, Waters ML, Tantillo DJ. Effects of Helix Macrodipole and Local Interactions on Catalysis of Acyl Transfer by α-Helical Peptides. ACS Catal 2015. [DOI: 10.1021/cs5019277] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Q. Nhu N. Nguyen
- Department of Chemistry, University of California−Davis, Davis, California 95616, United States
| | - Michael W. Lodewyk
- Physical Science Department, Butte College, Oroville, California 95965, United States
| | - Silvia Bezer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Michel R. Gagné
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Marcey L. Waters
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Dean J. Tantillo
- Department of Chemistry, University of California−Davis, Davis, California 95616, United States
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14
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Ramakrishna S, Padhi S, Priyakumar UD. Modeling the structure of SARS 3a transmembrane protein using a minimum unfavorable contact approach. J CHEM SCI 2015; 127:2159-2169. [PMID: 32218650 PMCID: PMC7090505 DOI: 10.1007/s12039-015-0982-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 09/02/2015] [Accepted: 09/04/2015] [Indexed: 12/11/2022]
Abstract
3a is an accessory protein from SARS coronavirus that is known to play a significant role in the proliferation of the virus by forming tetrameric ion channels. Although the monomeric units are known to consist of three transmembrane (TM) domains, there are no solved structures available for the complete monomer. The present study proposes a structural model for the transmembrane region of the monomer by employing our previously tested approach, which predicts potential orientations of TM α-helices by minimizing the unfavorable contact surfaces between the different TM domains. The best model structure comprising all three α-helices has been subjected to MD simulations to examine its quality. The TM bundle was found to form a compact and stable structure with significant intermolecular interactions. The structural features of the proposed model of 3a account for observations from previous experimental investigations on the activity of the protein. Further analysis indicates that residues from the TM2 and TM3 domains are likely to line the pore of the ion channel, which is in good agreement with a recent experimental study. In the absence of an experimental structure for the protein, the proposed structure can serve as a useful model for inferring structure-function relationships about the protein. The structure of the membrane protein 3a from SARS coronavirus is modeled using an approach that minimizes unfavorable contacts between transmembrane domains. A structure for a complete monomeric form of the protein thereby proposed is able to account for the behavior of the protein reported in previous experimental studies. ![]()
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Affiliation(s)
- S Ramakrishna
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad, 500 032 India
| | - Siladitya Padhi
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad, 500 032 India
| | - U Deva Priyakumar
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad, 500 032 India
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15
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Han E, Lee H. Effects of PEGylation on the binding interaction of magainin 2 and tachyplesin I with lipid bilayer surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:14214-14221. [PMID: 24160865 DOI: 10.1021/la4036985] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Poly(ethylene glycol) (PEG)-grafted magainin 2 and tachyplesin I were simulated with lipid bilayers. In the simulations of PEGylated magainin 2 and tachyplesin I in water, both peptides are wrapped by PEG chains. The α-helical structure of PEGylated magainin 2 is broken in water, while the β-sheet of PEGylated tachyplesin I keeps stable, similar to the structural behavior of unPEGylated peptides, in agreement with experiments. Simulations of PEGylated peptides with lipid bilayers show that PEG chains block the electrostatic interaction between cationic residues of peptides and anionic phosphates of lipids, leading to the less binding of the peptide to the bilayer surface, which is observed more significantly for magainin 2 than for tachyplesin I. Since the random-coiled magainin 2 can be more completely covered by PEGs than does the β-sheet tachyplesin I, the PEGylation effect on the decreased binding is larger for magainin 2, showing the dependence of PEGylation on the peptide structure. These simulation findings qualitatively support the experimental observation of the different extents of the reduced membrane-permeabilizing activity for PEGylated magainin 2 and tachyplesin I.
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Affiliation(s)
- Eol Han
- Department of Chemical Engineering, Dankook University , Yongin 448-701, South Korea
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16
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Peptide-lipid interactions: experiments and applications. Int J Mol Sci 2013; 14:18758-89. [PMID: 24036440 PMCID: PMC3794806 DOI: 10.3390/ijms140918758] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/27/2013] [Accepted: 08/28/2013] [Indexed: 02/06/2023] Open
Abstract
The interactions between peptides and lipids are of fundamental importance in the functioning of numerous membrane-mediated cellular processes including antimicrobial peptide action, hormone-receptor interactions, drug bioavailability across the blood-brain barrier and viral fusion processes. Moreover, a major goal of modern biotechnology is obtaining new potent pharmaceutical agents whose biological action is dependent on the binding of peptides to lipid-bilayers. Several issues need to be addressed such as secondary structure, orientation, oligomerization and localization inside the membrane. At the same time, the structural effects which the peptides cause on the lipid bilayer are important for the interactions and need to be elucidated. The structural characterization of membrane active peptides in membranes is a harsh experimental challenge. It is in fact accepted that no single experimental technique can give a complete structural picture of the interaction, but rather a combination of different techniques is necessary.
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17
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Venkatesh J, Park SW. Plastid genetic engineering in Solanaceae. PROTOPLASMA 2012; 249:981-99. [PMID: 22395455 PMCID: PMC3459085 DOI: 10.1007/s00709-012-0391-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 02/21/2012] [Indexed: 05/23/2023]
Abstract
Plastid genetic engineering has come of age, becoming today an attractive alternative approach for the expression of foreign genes, as it offers several advantages over nuclear transformants. Significant progress has been made in plastid genetic engineering in tobacco and other Solanaceae plants, through the use of improved regeneration procedures and transformation vectors with efficient promoters and untranslated regions. Many genes encoding for industrially important proteins and vaccines, as well as genes conferring important agronomic traits, have been stably integrated and expressed in the plastid genome. Despite these advances, it remains a challenge to achieve marked levels of plastid transgene expression in non-green tissues. In this review, we summarize the basic requirements of plastid genetic engineering and discuss the current status, limitations, and the potential of plastid transformation for expanding future studies relating to Solanaceae plants.
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Affiliation(s)
- Jelli Venkatesh
- Department of Molecular Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701 Republic of Korea
| | - Se Won Park
- Department of Molecular Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701 Republic of Korea
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Kawamoto S, Takasu M, Miyakawa T, Morikawa R, Oda T, Futaki S, Nagao H. Inverted micelle formation of cell-penetrating peptide studied by coarse-grained simulation: Importance of attractive force between cell-penetrating peptides and lipid head group. J Chem Phys 2011; 134:095103. [DOI: 10.1063/1.3555531] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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Wang Q, Hong G, Johnson GR, Pachter R, Cheung MS. Biophysical properties of membrane-active peptides based on micelle modeling: a case study of cell-penetrating and antimicrobial peptides. J Phys Chem B 2011; 114:13726-35. [PMID: 20939546 DOI: 10.1021/jp1069362] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigated the molecular mechanisms of short peptides interacting with membrane-mimetic systems. Three short peptides were selected for this study: penetratin as a cell-penetrating peptide (CPP), and temporin A and KSL as antimicrobial peptides (AMP). We investigated the detailed interactions of the peptides with dodecylphosphocholine (DPC) and sodium dodecyl sulfate (SDS) micelles, and the subsequent peptide insertion based on free energy calculations by using all-atomistic molecular dynamics simulations with the united atom force field and explicit solvent models. First, we found that the free energy barrier to insertion for the three peptides is dependent on the chemical composition of the micelles. Because of the favorable electrostatic interactions between the peptides and the headgroups of lipids, the insertion barrier into an SDS micelle is less than a DPC micelle. Second, the peptides' secondary structures may play a key role in their binding and insertion ability, particularly for amphiphilic peptides such as penetratin and KSL. The secondary structures with a stronger ability to bind with and insert into micelles are the ones that account for a smaller surface area of hydrophobic core, thus offering a possible criterion for peptide design with specific functionalities.
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Affiliation(s)
- Qian Wang
- Department of Physics, University of Houston, Houston, Texas, USA
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20
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Raudino A, Sarpietro MG, Pannuzzo M. The thermodynamics of simple biomembrane mimetic systems. JOURNAL OF PHARMACY AND BIOALLIED SCIENCES 2011; 3:15-38. [PMID: 21430953 PMCID: PMC3053513 DOI: 10.4103/0975-7406.76462] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 10/09/2010] [Accepted: 12/15/2010] [Indexed: 11/04/2022] Open
Abstract
Insight into the forces governing a system is essential for understanding its behavior and function. Thermodynamic investigations provide a wealth of information that is not, or is hardly, available from other methods. This article reviews thermodynamic approaches and assays to measure collective properties such as heat adsorption / emission and volume variations. These methods can be successfully applied to the study of lipid vesicles (liposomes) and biological membranes. With respect to instrumentation, differential scanning calorimetry, pressure perturbation calorimetry, isothermal titration calorimetry, dilatometry, and acoustic techniques aimed at measuring the isothermal and adiabatic processes, two- and three-dimensional compressibilities are considered. Applications of these techniques to lipid systems include the measurement of different thermodynamic parameters and a detailed characterization of thermotropic, barotropic, and lyotropic phase behavior. The membrane binding and / or partitioning of solutes (proteins, peptides, drugs, surfactants, ions, etc.) can also be quantified and modeled. Many thermodynamic assays are available for studying the effect of proteins and other additives on membranes, characterizing non-ideal mixing, domain formation, bilayer stability, curvature strain, permeability, solubilization, and fusion. Studies of membrane proteins in lipid environments elucidate lipid-protein interactions in membranes. Finally, a plethora of relaxation phenomena toward equilibrium thermodynamic structures can be also investigated. The systems are described in terms of enthalpic and entropic forces, equilibrium constants, heat capacities, partial volume changes, volume and area compressibility, and so on, also shedding light on the stability of the structures and the molecular origin and mechanism of the structural changes.
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Affiliation(s)
- Antonio Raudino
- University of Catania, Department of Chemistry, Viale A. Doria 6-95125, Catania, Italy
| | | | - Martina Pannuzzo
- University of Catania, Department of Chemistry, Viale A. Doria 6-95125, Catania, Italy
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21
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Galloux M, Libersou S, Alves ID, Marquant R, Salgado GF, Rezaei H, Lepault J, Delmas B, Bouaziz S, Morellet N. NMR structure of a viral peptide inserted in artificial membranes: a view on the early steps of the birnavirus entry process. J Biol Chem 2010; 285:19409-21. [PMID: 20385550 PMCID: PMC2885221 DOI: 10.1074/jbc.m109.076083] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 03/08/2010] [Indexed: 11/06/2022] Open
Abstract
Nonenveloped virus must penetrate the cellular membrane to access the cytoplasm without the benefit of membrane fusion. For birnavirus, one of the peptides present in the virus capsid, pep46 for infectious bursal disease virus, is able to induce pores into membranes as an intermediate step of the birnavirus-penetration pathway. Using osmotic protection experiments, we demonstrate here that pep46 and its pore-forming N-terminal moiety (pep22) form pores of different diameters, 5-8 and 2-4 nm, respectively, showing that both pep46 moieties participate to pore formation. The solution structures of pep46, pep22, and pep24 (the pep46 C-terminal moiety) in different hydrophobic environments and micelles determined by (1)H NMR studies provide structural insights of the pep46 domain interaction. In CDCl(3)/CD(3)OH mixture and in dodecylphosphocholine micelles, the N-terminal domain of pep46 is structured in a long kinked helix, although the C terminus is structured in one or two helices depending upon the solvents used. We also show that the folding and the proline isomerization status of pep46 depend on the type of hydrophobic environment. NMR spectroscopy with labeled phospholipid micelles, differential scanning calorimetry, and plasmon waveguide resonance studies show the peptides lie parallel to the lipid-water interface, perturbing the fatty acid chain packing. All these data lead to a model in which the two domains of pep46 interact with the membrane to form pores.
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Affiliation(s)
- Marie Galloux
- From the Unité de Pharmacologie Chimique et Génétique, CNRS, UMR 8151, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, 4 Avenue de l'Observatoire, Paris, F-75270 Cedex 06
- the Unité de Virologie et Immunologie Moléculaires, UR892, Bâtiment de Biotechnologies, INRA, Domaine de Vilvert, F-78350 Jouy-en-Josas
| | - Sonia Libersou
- the CNRS UMR 2472, INRA 1157, Virologie Moléculaire et Structurale, 1 Avenue de la Terrasse, F-91198 Gif-sur-Yvette, France
| | - Isabel D. Alves
- the UPMC Paris 06, CNRS, UMR 7203, Laboratoire des BioMolécules, FR 2769, Case Courier 182, 4 Place Jussieu, 75252 Paris Cedex 05, and
| | - Rodrigue Marquant
- From the Unité de Pharmacologie Chimique et Génétique, CNRS, UMR 8151, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, 4 Avenue de l'Observatoire, Paris, F-75270 Cedex 06
| | - Gilmar F. Salgado
- the UPMC Paris 06, CNRS, UMR 7203, Laboratoire des BioMolécules, FR 2769, Case Courier 182, 4 Place Jussieu, 75252 Paris Cedex 05, and
| | - Human Rezaei
- the Unité de Virologie et Immunologie Moléculaires, UR892, Bâtiment de Biotechnologies, INRA, Domaine de Vilvert, F-78350 Jouy-en-Josas
| | - Jean Lepault
- the CNRS UMR 2472, INRA 1157, Virologie Moléculaire et Structurale, 1 Avenue de la Terrasse, F-91198 Gif-sur-Yvette, France
| | - Bernard Delmas
- the Unité de Virologie et Immunologie Moléculaires, UR892, Bâtiment de Biotechnologies, INRA, Domaine de Vilvert, F-78350 Jouy-en-Josas
| | - Serge Bouaziz
- From the Unité de Pharmacologie Chimique et Génétique, CNRS, UMR 8151, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, 4 Avenue de l'Observatoire, Paris, F-75270 Cedex 06
| | - Nelly Morellet
- From the Unité de Pharmacologie Chimique et Génétique, CNRS, UMR 8151, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, 4 Avenue de l'Observatoire, Paris, F-75270 Cedex 06
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Can antimicrobial peptides scavenge around a cell in less than a second? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:228-34. [DOI: 10.1016/j.bbamem.2009.08.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 08/19/2009] [Accepted: 08/31/2009] [Indexed: 11/20/2022]
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23
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Expression of a synthesized gene encoding cationic peptide cecropin B in transgenic tomato plants protects against bacterial diseases. Appl Environ Microbiol 2009; 76:769-75. [PMID: 19966019 DOI: 10.1128/aem.00698-09] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cationic lytic peptide cecropin B (CB), isolated from the giant silk moth (Hyalophora cecropia), has been shown to effectively eliminate Gram-negative and some Gram-positive bacteria. In this study, the effects of chemically synthesized CB on plant pathogens were investigated. The S(50)s (the peptide concentrations causing 50% survival of a pathogenic bacterium) of CB against two major pathogens of the tomato, Ralstonia solanacearum and Xanthomonas campestris pv. vesicatoria, were 529.6 microg/ml and 0.29 microg/ml, respectively. The CB gene was then fused to the secretory signal peptide (sp) sequence from the barley alpha-amylase gene, and the new construct, pBI121-spCB, was used for the transformation of tomato plants. Integration of the CB gene into the tomato genome was confirmed by PCR, and its expression was confirmed by Western blot analyses. In vivo studies of the transgenic tomato plant demonstrated significant resistance to bacterial wilt and bacterial spot. The levels of CB expressed in transgenic tomato plants ( approximately 0.05 microg in 50 mg of leaves) were far lower than the S(50) determined in vitro. CB transgenic tomatoes could therefore be a new mode of bioprotection against these two plant diseases with significant agricultural applications.
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24
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Ulmschneider MB, Ulmschneider JP. Membrane adsorption, folding, insertion and translocation of synthetic trans-membrane peptides. Mol Membr Biol 2009; 25:245-57. [DOI: 10.1080/09687680802020313] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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25
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Leite JRSA, Brand GD, Silva LP, Kückelhaus SAS, Bento WRC, Araújo ALT, Martins GR, Lazzari AM, Bloch C. Dermaseptins from Phyllomedusa oreades and Phyllomedusa distincta: Secondary structure, antimicrobial activity, and mammalian cell toxicity. Comp Biochem Physiol A Mol Integr Physiol 2008; 151:336-343. [PMID: 17442605 DOI: 10.1016/j.cbpa.2007.03.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Revised: 03/13/2007] [Accepted: 03/13/2007] [Indexed: 10/23/2022]
Abstract
The present study reports the structural characteristics, the biological activities, and preliminary clinical investigations of three synthetic members of the dermaseptin family of antimicrobial peptides. The three peptides showed similar tendencies to form alpha-helical structures in non-polar media. The antimicrobial activity towards bacteria and fungi was determined in the micromolar concentration and the peptides did not influenced peritoneal cells viability. One of the peptides was intravenously administered in mice at concentrations similar to those of antibiotics employed in bacterial/fungal infections and it did not cause any detectable changes in cells and tissues.
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Affiliation(s)
- José Roberto S A Leite
- Laboratório de Espectrometria de Massa, Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) - Recursos Genéticos e Biotecnologia, Estação Parque Biológico, Final W5, Asa Norte, Brasília, DF, 70770-900, Brazil; Campus Ministro Reis Velloso, Universidade Federal do Piauí - UFPI, Parnaíba, Piauí, 64202-020, PI, Brazil.
| | - Guilherme D Brand
- Laboratório de Espectrometria de Massa, Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) - Recursos Genéticos e Biotecnologia, Estação Parque Biológico, Final W5, Asa Norte, Brasília, DF, 70770-900, Brazil; Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF, Brazil
| | - Luciano P Silva
- Laboratório de Espectrometria de Massa, Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) - Recursos Genéticos e Biotecnologia, Estação Parque Biológico, Final W5, Asa Norte, Brasília, DF, 70770-900, Brazil
| | | | | | | | | | | | - Carlos Bloch
- Laboratório de Espectrometria de Massa, Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) - Recursos Genéticos e Biotecnologia, Estação Parque Biológico, Final W5, Asa Norte, Brasília, DF, 70770-900, Brazil.
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26
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Ulmschneider JP, Ulmschneider MB. Sampling efficiency in explicit and implicit membrane environments studied by peptide folding simulations. Proteins 2008; 75:586-97. [DOI: 10.1002/prot.22270] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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27
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Broniatowski M, Vila-Romeu N, Dynarowicz-Łatka P. Two-Dimensional Miscibility Studies of Alamethicin and Selected Film-Forming Molecules. J Phys Chem B 2008; 112:7762-70. [DOI: 10.1021/jp800234k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Marcin Broniatowski
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland, and Faculty of Sciences, Department of Physical Chemistry, University of Vigo, Campus Ourense, As Lagoas s/n, 32004 Ourense, Spain
| | - Nuria Vila-Romeu
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland, and Faculty of Sciences, Department of Physical Chemistry, University of Vigo, Campus Ourense, As Lagoas s/n, 32004 Ourense, Spain
| | - Patrycja Dynarowicz-Łatka
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland, and Faculty of Sciences, Department of Physical Chemistry, University of Vigo, Campus Ourense, As Lagoas s/n, 32004 Ourense, Spain
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28
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Abstract
On the basis of previous evidence that amphipathic helical peptides accelerate Factor IXa activation of Factor X [Blostein, Rigby, Furie, Furie and Gilbert (2000) Biochemistry 39, 12000–12006], the present study was designed to assess the procoagulant activity of an IAP (ideal amphipathic peptide) of Lys7Leu15 composition. The results show that IAP accelerates Factor X activation by Factor IXa in a concentration-dependent manner and accelerates thrombin generation by Factor Xa with a comparable peptide- and substrate-concentration-dependence. A scrambled helical peptide with the same amino acid composition as IAP, but with its amphipathicity abolished, eliminated most of the aforementioned effects. The Gla (γ-carboxyglutamic acid)-rich domain of Factor X is required for IAP activity, suggesting that this peptide behaves as a phospholipid membrane. This hypothesis was confirmed, using fluorescence spectroscopy, by demonstrating direct binding between IAP and the Gla-rich domain of Factor X. In addition, the catalytic efficiencies of the tenase and prothrombinase enzymatic complexes, containing cofactors Factor VIIIa and Factor Va respectively, are enhanced by IAP. Finally, we show that IAP delays clot lysis in vitro. In summary, these observations demonstrate that IAP not only enhances essential procoagulant reactions required for fibrin generation, but also inhibits fibrinolysis, suggesting a potential role for IAP as a haemostatic agent.
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29
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Khandelia H, Ipsen JH, Mouritsen OG. The impact of peptides on lipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1528-36. [PMID: 18358231 DOI: 10.1016/j.bbamem.2008.02.009] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 02/22/2008] [Accepted: 02/24/2008] [Indexed: 11/26/2022]
Abstract
We review the fundamental strategies used by small peptides to associate with lipid membranes and how the different strategies impact on the structure and dynamics of the lipids. In particular we focus on the binding of amphiphilic peptides by electrostatic and hydrophobic forces, on the anchoring of peptides to the bilayer by acylation and prenylation, and on the incorporation of small peptides that form well-defined channels. The effect of lipid-peptide interactions on the lipids is characterized in terms of lipid acyl-chain order, membrane thickness, membrane elasticity, permeability, lipid-domain and annulus formation, as well as acyl-chain dynamics. The different situations are illustrated by specific cases for which experimental observations can be interpreted and supplemented by theoretical modeling and simulations. A comparison is made with the effect on lipids of trans-membrane proteins. The various cases are discussed in the context of the possible roles played by lipid-peptide interactions for the biological, physiological, and pharmacological function of peptides.
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Affiliation(s)
- Himanshu Khandelia
- MEMPHYS-Center for Biomembrane Physics, Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, Odense M, Denmark
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30
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Chen X, Wang J, Kristalyn CB, Chen Z. Real-time structural investigation of a lipid bilayer during its interaction with melittin using sum frequency generation vibrational spectroscopy. Biophys J 2007; 93:866-75. [PMID: 17483186 PMCID: PMC1913150 DOI: 10.1529/biophysj.106.099739] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interactions between membrane bilayers and peptides/proteins are ubiquitous throughout a cell. To determine the structure of membrane bilayers and the associated peptides/proteins, model systems such as supported lipid bilayers are often used. It has been difficult to directly investigate the interactions between a single membrane bilayer and peptides/proteins without exogenous labeling. In this work we demonstrate that sum frequency generation vibrational spectroscopy can be employed to study the interactions between peptides/proteins and a single lipid bilayer in real time, in situ, and without exogenous labeling. Using melittin and a dipalmitoyl phosphatidylglycerol bilayer as a model system, we monitored the C-H and C-D stretching signals from isotopically symmetric or asymmetric dipalmitoyl phosphatidylglycerol bilayers during their interaction with melittin. It has been found that the extent and kinetics of bilayer perturbation induced by melittin are very sensitive to melittin concentration. Such concentration dependence is correlated to melittin's mode of action. Melittin is found to function via the early and late stage of the carpet model at low and high concentrations, respectively, whereas the toroidal model is probable at intermediate concentrations. This research illustrates the potential of sum frequency generation as a biophysical technique to monitor individual leaflet structure of lipid bilayers in real time during their interactions with biomolecules.
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Affiliation(s)
- Xiaoyun Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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31
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Ulmschneider MB, Ulmschneider JP, Sansom MSP, Di Nola A. A generalized born implicit-membrane representation compared to experimental insertion free energies. Biophys J 2007; 92:2338-49. [PMID: 17218457 PMCID: PMC1864825 DOI: 10.1529/biophysj.106.081810] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An implicit-membrane representation based on the generalized Born theory of solvation has been developed. The method was parameterized against the water-to-cyclohexane insertion free energies of hydrophobic side-chain analogs. Subsequently, the membrane was compared with experimental data from translocon inserted polypeptides and validated by comparison with an independent dataset of six membrane-associated peptides and eight integral membrane proteins of known structure and orientation. Comparison of the insertion energy of alpha-helical model peptides with the experimental values from the biological hydrophobicity scale of Hessa et al. gave a correlation of 93% with a mean unsigned error of 0.64 kcal/mol, when charged residues were ignored. The membrane insertion energy was found to be dependent on residue position. This effect is particularly pronounced for charged and polar residues, which strongly prefer interfacial locations. All integral membrane proteins investigated orient and insert correctly into the implicit-membrane model. Remarkably, the membrane model correctly predicts a partially inserted configuration for the monotopic membrane protein cyclooxygenase, matching experimental and theoretical predictions. To test the applicability and usefulness of the implicit-membrane method, molecular simulations of influenza A M2 as well as the glycophorin A dimer were performed. Both systems remain structurally stable and integrated into the membrane.
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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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33
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Benaki D, Zikos C, Evangelou A, Livaniou E, Vlassi M, Mikros E, Pelecanou M. Solution structure of Ser14Gly-humanin, a potent rescue factor against neuronal cell death in Alzheimer's disease. Biochem Biophys Res Commun 2006; 349:634-42. [PMID: 16945331 DOI: 10.1016/j.bbrc.2006.08.087] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Accepted: 08/16/2006] [Indexed: 01/28/2023]
Abstract
The NMR solution study of Ser14Gly-humanin (S14G-HN), a 1000-fold more potent derivative of humanin (HN), is reported. HN is 24-residue peptide that selectively suppresses neuronal cell death caused by Alzheimer's disease (AD)-specific insults and offers hope for the development of a cure against AD. In aqueous solution the NMR data show that S14G-HN is a flexible peptide with turn-like structures in its conformational ensemble distributed over an extensive part of its sequence from Pro3 to Glu15. In the more lipophilic environment of 30% TFE, an alpha-helical structure spanning residues Phe6 to Thr13 is identified. Comparison of these findings to the NMR structure of the parent HN and to existing structure-function relationship literature data outlines the important for activity structural features for this class of neuroprotective peptides, and brings forth flexibility as an important characteristic that may facilitate interactions with functional counterparts of the neuroprotection pathway.
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Affiliation(s)
- Dimitra Benaki
- Institute of Biology, NCSR Demokritos 15310 Athens, Greece
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34
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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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35
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Efremov RG, Vereshaga YA, Volynsky PE, Nolde DE, Arseniev AS. Association of transmembrane helices: what determines assembling of a dimer? J Comput Aided Mol Des 2006; 20:27-45. [PMID: 16775778 DOI: 10.1007/s10822-006-9034-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Accepted: 01/17/2006] [Indexed: 11/28/2022]
Abstract
Self-association of two hydrophobic alpha-helices is studied via unrestrained Monte Carlo (MC) simulations in a hydrophobic slab described by an effective potential. The system under study represents two transmembrane (TM) segments of human glycophorin A (GpA), which form homo-dimers in membranes. The influence of TM electrostatic potential, thickness and hydrophobicity degree of lipid bilayer is investigated. It is shown that the membrane environment stabilizes alpha-helical conformation of GpA monomers, induces their TM insertion and facilitates inter-helical contacts. Head-to-head orientation of the helices is promoted by the voltage difference across the membrane. Subsequent "fine-tuned" assembling of the dimer is mediated by van der Waals interactions. Only the models of dimer, calculated in a hydrophobic slab with applied voltage agree with experimental data, while simulations in vacuo or without TM voltage fail to give reasonable results. The moderate structural heterogeneity of GpA dimers (existence of several groups of states with close energies) is proposed to reflect their equilibrium dynamics in membrane-mimics. The calculations performed for GpA mutants G83A and G86L permit rationalization of mutagenesis data for them. The results of Monte Carlo simulations critically depend on the parameters of the membrane model: adequate description of helix association is achieved in the water-cyclohexane-water system with the membrane thickness 30-34 A, while in membranes with different hydrophobicities and thickness unrealistic conformations of the dimer are found. The computational approach permits efficient prediction of TM helical oligomers based solely on the sequences of interacting peptides.
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Affiliation(s)
- Roman G Efremov
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya, 16/10, V-437, 117997 GSP, Moscow, Russia.
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36
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Abstract
A molecular level model for lipid bilayers is presented. Lipids are represented by rigid, asymmetric, soft spherocylinders in implicit solvent. A simple three parameter potential between pairs of lipids gives rise to a rich assortment of phases including (but not limited to) micelles, fluid bilayers, and gel-like bilayers. Monte Carlo simulations have been carried out to verify self-assembly, characterize the phases corresponding to different potential parametrizations, and to quantify the physical properties associated with those parameter sets corresponding to fluid bilayer behavior. The studied fluid bilayers have compressibility moduli in agreement with experimental systems, but display bending moduli at least three times larger than typical biological membranes without cholesterol.
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Affiliation(s)
- Grace Brannigan
- Department of Physics and Astronomy, University of California, Santa Barbara, California 93106, USA
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37
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Chekmenev EY, Jones SM, Nikolayeva YN, Vollmar BS, Wagner TJ, Gor'kov PL, Brey WW, Manion MN, Daugherty KC, Cotten M. High-Field NMR Studies of Molecular Recognition and Structure−Function Relationships in Antimicrobial Piscidins at the Water−Lipid Bilayer Interface. J Am Chem Soc 2006; 128:5308-9. [PMID: 16620079 DOI: 10.1021/ja058385e] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High magnetic field solid-state NMR was performed on amphipathic cationic antimicrobial peptides from fish to characterize their secondary structure and orientation in hydrated phospholipid bilayers. High-resolution distance and orientational restraints on 13C- and 15N-labeled amidated piscidins 1 and 3 provided site-specific information establishing alpha-helicity and an orientation parallel to the membrane surface. Few membrane-bound natural peptides with this topology have been structurally studied at high resolution in the presence of hydrated lipid bilayers. This orientation was foreseen since the partitioning of amphipathic cationic antimicrobial peptides at the water-bilayer interface allows for favorable peptide-lipid interactions, and it may be related to the mechanism of action. The enhanced resolution obtained at 900 MHz evidences a determinant advantage of ultra-high-field NMR for the structural determination of multiple-labeled peptides and proteins.
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Affiliation(s)
- Eduard Y Chekmenev
- Center for Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
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38
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Ulmschneider MB, Sansom MSP, Di Nola A. Properties of integral membrane protein structures: derivation of an implicit membrane potential. Proteins 2006; 59:252-65. [PMID: 15723347 DOI: 10.1002/prot.20334] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Distributions of each amino acid in the trans-membrane domain were calculated as a function of the membrane normal using all currently available alpha-helical membrane protein structures with resolutions better than 4 A. The results were compared with previous sequence- and structure-based analyses. Calculation of the average hydrophobicity along the membrane normal demonstrated that the protein surface in the membrane domain is in fact much more hydrophobic than the protein core. While hydrophobic residues dominate the membrane domain, the interfacial regions of membrane proteins were found to be abundant in the small residues glycine, alanine, and serine, consistent with previous studies on membrane protein packing. Charged residues displayed nonsymmetric distributions with a preference for the intracellular interface. This effect was more prominent for Arg and Lys resulting in a direct confirmation of the positive inside rule. Potentials of mean force along the membrane normal were derived for each amino acid by fitting Gaussian functions to the residue distributions. The individual potentials agree well with experimental and theoretical considerations. The resulting implicit membrane potential was tested on various membrane proteins as well as single trans-membrane alpha-helices. All membrane proteins were found to be at an energy minimum when correctly inserted into the membrane. For alpha-helices both interfacial (i.e. surface bound) and inserted configurations were found to correspond to energy minima. The results demonstrate that the use of trans-membrane amino acid distributions to derive an implicit membrane representation yields meaningful residue potentials.
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39
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Sharadadevi A, Sivakamasundari C, Nagaraj R. Amphipathic alpha-helices in proteins: results from analysis of protein structures. Proteins 2006; 59:791-801. [PMID: 15822124 DOI: 10.1002/prot.20459] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Amphipathic alpha-helices play a crucial role in mediating the interaction of peptides and proteins with membranes. We have analyzed protein structures for the occurrence of 18-residue amphipathic helices. We find several of these alpha-helices having average hydrophobic moments and average hydrophobicities that would favor their interaction with membranes. We have analyzed the distribution of net charge, helix length, normalized frequency of occurrence, and propensities of the 20 amino acids in the delineated 18-residue helices. We have observed distinct differences in the frequencies of occurrence of polar and hydrophobic amino acids at positions 1-18 in amphipathic and nonamphipathic helices. There are also differences in propensities of the 20 amino acids to occur at positions 1-18 of amphipathic and nonamphipathic helices. Synthetic peptides corresponding to some of these surface-seeking helices do possess antibacterial and/or hemolytic activities. Knowledge of the distribution of charges in 18-residue surface-seeking amphipathic alpha-helices, as well as propensity of occurrence of amino acids at various positions, would be useful inputs in the de novo design of amphipathic peptides.
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Affiliation(s)
- Ambure Sharadadevi
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India
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40
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Vidal JR, Kikkert JR, Malnoy MA, Wallace PG, Barnard J, Reisch BI. Evaluation of Transgenic ‘Chardonnay’ (Vitis vinifera) Containing Magainin Genes for Resistance to Crown Gall and Powdery Mildew. Transgenic Res 2006; 15:69-82. [PMID: 16475011 DOI: 10.1007/s11248-005-4423-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Accepted: 10/25/2005] [Indexed: 10/25/2022]
Abstract
Magainins, short peptides with broad-spectrum antimicrobial activity in vitro, were assayed for their ability to confer resistance to pathogens in transgenic grapevines. Embryogenic cell suspensions of 'Chardonnay' (Vitis vinifera L.) were co-transformed by microprojectile bombardment with a plasmid carrying the npt-II gene and a second plasmid harboring either a natural magainin-2 (mag2) or a synthetic derivative (MSI99) gene. Magainin genes and the marker gene were driven by Arabidopsis ubiquitin-3 and ubiquitin-11 promoters, respectively. A total of 10 mag2 and 9 MSI99 regenerated lines were studied by Southern blot hybridization, which showed 1-6 transgene integration events into the plant genome. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) revealed a variable range in transcription levels among mag2 and MSI99 lines. A positive correlation between number of integration events and transcription level was observed (p<0.05). Plants were acclimated and challenged in the greenhouse with either Agrobacterium vitis strains (bacterial crown gall pathogen) at 10(8) cfu/ml or Uncinula necator (fungal powdery mildew pathogen) at 10(5) conidia/ml for evaluation of disease resistance. A total of 6 mag2 and 5 MSI99 lines expressing the antimicrobial genes exhibited significant reductions of crown gall symptoms as compared to non-transformed controls. However, only two mag2 lines showed measurable symptom reductions in response to U. necator, but not strong resistance. Our results suggest that the expression of magainin-type genes in grapevines may be more effective against bacteria than fungi. Additional strategies to enhance transgene expression and the spectrum of resistance to grape diseases are suggested.
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Affiliation(s)
- José R Vidal
- Department of Horticultural Sciences, New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456, USA
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41
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Abstract
All sequenced peptide toxins of the cecropin, pleurocidin and dermaceptin/ceratotoxin families in the National Center for Biotechnology Information (NCBI) database as of May 2005 were identified and shown to comprise a single superfamily. The peptide sequences were multiply aligned, revealing conserved residues that may play roles in structure and function. Signature sequences were derived for each of the 3 constituent families. Phylogenetic analyses revealed the relationships of these peptides to each other, and average hydropathy/amphipathicity studies provided structural information. This study serves to characterize a large superfamily of toxic peptides that perform host defense functions in a range of animal kingdoms.
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Affiliation(s)
- Dorjee G Tamang
- Division of Biological Sciences, University of California at San Diego, La Jolla 92093-0116, USA
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42
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Ulmschneider MB, Sansom MSP, Di Nola A. Evaluating tilt angles of membrane-associated helices: comparison of computational and NMR techniques. Biophys J 2005; 90:1650-60. [PMID: 16339877 PMCID: PMC1367316 DOI: 10.1529/biophysj.105.065367] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A computational method to calculate the orientation of membrane-associated alpha-helices with respect to a lipid bilayer has been developed. It is based on a previously derived implicit membrane representation, which was parameterized using the structures of 46 alpha-helical membrane proteins. The method is validated by comparison with an independent data set of six transmembrane and nine antimicrobial peptides of known structure and orientation. The minimum energy orientations of the transmembrane helices were found to be in good agreement with tilt and rotation angles known from solid-state NMR experiments. Analysis of the free-energy landscape found two types of minima for transmembrane peptides: i), Surface-bound configurations with the helix long axis parallel to the membrane, and ii), inserted configurations with the helix spanning the membrane in a perpendicular orientation. In all cases the inserted configuration also contained the global energy minimum. Repeating the calculations with a set of solution NMR structures showed that the membrane model correctly distinguishes native transmembrane from nonnative conformers. All antimicrobial peptides investigated were found to orient parallel and bind to the membrane surface, in agreement with experimental data. In all cases insertion into the membrane entailed a significant free-energy penalty. An analysis of the contributions of the individual residue types confirmed that hydrophobic residues are the main driving force behind membrane protein insertion, whereas polar, charged, and aromatic residues were found to be important for the correct orientation of the helix inside the membrane.
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43
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Glättli A, Chandrasekhar I, van Gunsteren WF. A molecular dynamics study of the bee venom melittin in aqueous solution, in methanol, and inserted in a phospholipid bilayer. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2005; 35:255-67. [PMID: 16322979 DOI: 10.1007/s00249-005-0033-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Revised: 10/05/2005] [Accepted: 10/08/2005] [Indexed: 11/27/2022]
Abstract
The structural properties of melittin, a small amphipathic peptide found in the bee venom, are investigated in three different environments by molecular dynamics simulation. Long simulations have been performed for monomeric melittin solvated in water, in methanol, and shorter ones for melittin inserted in a dimyristoylphosphatidylcholine bilayer. The resulting trajectories were analysed in terms of structural properties of the peptide and compared to the available NMR data. While in water and methanol solution melittin is observed to partly unfold, the peptide retains its structure when embedded in a lipid bilayer. The latter simulation shows good agreement with the experimentally derived (3)J-coupling constants. Generally, it appears that higher the stability of the helical conformation of melittin, lower is the dielectric permittivity of the environment. In addition, peptide-lipid interactions were investigated showing that the C-terminus of the peptide provides an anchor to the lipid bilayer by forming hydrogen bonds with the lipid head groups.
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Affiliation(s)
- Alice Glättli
- Laboratorium für Physikalische Chemie, Swiss Federal Institute of Technology, ETH Hönggerberg HCI, 8093 Zürich, Switzerland
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44
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Appelt C, Eisenmenger F, Kühne R, Schmieder P, Söderhäll JA. Interaction of the antimicrobial peptide cyclo(RRWWRF) with membranes by molecular dynamics simulations. Biophys J 2005; 89:2296-306. [PMID: 16040748 PMCID: PMC1366731 DOI: 10.1529/biophysj.105.063040] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Antimicrobial peptides have gained a lot of interest in recent years due to their potential use as a new generation of antibiotics. It is believed that this type of relatively short, amphipathic, cationic peptide targets the bacterial membrane, and destroys the chemical gradients over the membrane via formation of stable or transient pores. Here we use the NMR structure of cyclo(RRWWRF) in a series of molecular dynamics simulations in membranes at various peptide/lipid ratios. We observe that the NMR structure of the peptide is still stable after 100 ns simulation. At a peptide/lipid ratio of 2:128, the membrane is only a little affected compared to a pure dipalmitoylphosphatidylcholine lipid membrane, but at a ratio of 12:128, the water-lipid interface becomes more fuzzy, the water molecules can reach deeper into the hydrophobic core, and the water penetration free-energy barrier changes. Moreover, we observe that the area per lipid decreases and the deuterium order parameters increase in the presence of the peptide. We suggest that the changes in the hydrophobic core, together with the changes in the headgroups, result in an imbalance of the membrane and that it is thus not an efficient hydrophobic barrier in the presence of the peptides, independent of pore formation.
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Affiliation(s)
- Christian Appelt
- Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
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45
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Deslouches B, Phadke SM, Lazarevic V, Cascio M, Islam K, Montelaro RC, Mietzner TA. De novo generation of cationic antimicrobial peptides: influence of length and tryptophan substitution on antimicrobial activity. Antimicrob Agents Chemother 2005; 49:316-22. [PMID: 15616311 PMCID: PMC538858 DOI: 10.1128/aac.49.1.316-322.2005] [Citation(s) in RCA: 198] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Comparison of human immunodeficiency virus lentiviral lytic peptide 1 with other host-derived peptides indicates that antimicrobial properties of membrane-active peptides are markedly influenced by their cationic, hydrophobic, and amphipathic properties. Many common themes, such as Arg composition of the cationic face of an amphipathic helix and the importance of maintaining the hydrophobic face, have been deduced from these observations. These studies suggest that a peptide with these structural properties can be derived de novo by using only a few strategically positioned amino acids. However, the effects of length and helicity on antimicrobial activity and selectivity have not been objectively evaluated in the context of this motif. To address these structure-function issues, multimers of a 12-residue lytic base unit (LBU) peptide composed only of Arg and Val residues aligned to form idealized amphipathic helices were designed. Bacterial killing assays and circular dichroism analyses reveal a strong correlation between antibacterial activity, peptide length, and propensity to form a helix in solvent mimicking the environment of a membrane. Increasing peptide length beyond two LBUs (24-residue peptides) resulted in no appreciable increase in antimicrobial activity. Derivatives (WLBU) of the LBU series were further engineered by substituting Trp residues in the hydrophobic domains. The 24-residue WLBU2 peptide was active at physiologic NaCl concentrations against Staphylococcus aureus and mucoid and nonmucoid strains of Pseudomonas aeruginosa. Further, WLBU2 displayed the highest antibacterial selectivity of all peptides evaluated in the present study by using a coculture model of P. aeruginosa and primary human skin fibroblasts. These findings provide fundamental information toward the de novo design of an antimicrobial peptide useful for the management of infectious diseases.
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Affiliation(s)
- Berthony Deslouches
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Lothrop St., Pittsburgh, PA 15261, USA
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46
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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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47
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Ash WL, Zlomislic MR, Oloo EO, Tieleman DP. Computer simulations of membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1666:158-89. [PMID: 15519314 DOI: 10.1016/j.bbamem.2004.04.012] [Citation(s) in RCA: 204] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2004] [Accepted: 04/29/2004] [Indexed: 11/30/2022]
Abstract
Computer simulations are rapidly becoming a standard tool to study the structure and dynamics of lipids and membrane proteins. Increasing computer capacity allows unbiased simulations of lipid and membrane-active peptides. With the increasing number of high-resolution structures of membrane proteins, which also enables homology modelling of more structures, a wide range of membrane proteins can now be simulated over time spans that capture essential biological processes. Longer time scales are accessible by special computational methods. We review recent progress in simulations of membrane proteins.
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Affiliation(s)
- Walter L Ash
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary AB, Canada T2N 1N4
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48
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Gambhir A, Hangyás-Mihályné G, Zaitseva I, Cafiso DS, Wang J, Murray D, Pentyala SN, Smith SO, McLaughlin S. Electrostatic sequestration of PIP2 on phospholipid membranes by basic/aromatic regions of proteins. Biophys J 2004; 86:2188-207. [PMID: 15041659 PMCID: PMC1304070 DOI: 10.1016/s0006-3495(04)74278-2] [Citation(s) in RCA: 247] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2003] [Accepted: 11/11/2003] [Indexed: 11/21/2022] Open
Abstract
The basic effector domain of myristoylated alanine-rich C kinase substrate (MARCKS), a major protein kinase C substrate, binds electrostatically to acidic lipids on the inner leaflet of the plasma membrane; interaction with Ca2+/calmodulin or protein kinase C phosphorylation reverses this binding. Our working hypothesis is that the effector domain of MARCKS reversibly sequesters a significant fraction of the L-alpha-phosphatidyl-D-myo-inositol 4,5-bisphosphate (PIP2) on the plasma membrane. To test this, we utilize three techniques that measure the ability of a peptide corresponding to its effector domain, MARCKS(151-175), to sequester PIP2 in model membranes containing physiologically relevant fractions (15-30%) of the monovalent acidic lipid phosphatidylserine. First, we measure fluorescence resonance energy transfer from Bodipy-TMR-PIP2 to Texas Red MARCKS(151-175) adsorbed to large unilamellar vesicles. Second, we detect quenching of Bodipy-TMR-PIP2 in large unilamellar vesicles when unlabeled MARCKS(151-175) binds to vesicles. Third, we identify line broadening in the electron paramagnetic resonance spectra of spin-labeled PIP2 as unlabeled MARCKS(151-175) adsorbs to vesicles. Theoretical calculations (applying the Poisson-Boltzmann relation to atomic models of the peptide and bilayer) and experimental results (fluorescence resonance energy transfer and quenching at different salt concentrations) suggest that nonspecific electrostatic interactions produce this sequestration. Finally, we show that the PLC-delta1-catalyzed hydrolysis of PIP2, but not binding of its PH domain to PIP2, decreases markedly as MARCKS(151-175) sequesters most of the PIP2.
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Affiliation(s)
- Alok Gambhir
- Department of Physics and Astronomy, SUNY Stony Brook, Stony Brook, New York 11794, USA
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49
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Zhang L, Lin J, Ji G. Membrane anchoring of the AgrD N-terminal amphipathic region is required for its processing to produce a quorum-sensing pheromone in Staphylococcus aureus. J Biol Chem 2004; 279:19448-56. [PMID: 15001569 DOI: 10.1074/jbc.m311349200] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Quorum-sensing pheromones are signal molecules that are secreted from Gram-positive bacteria and utilized by these bacteria to communicate among individual cells to regulate their activities as a group through a cell density-sensing mechanism. Typically, these pheromones are processed from precursor polypeptides. The mechanisms of trafficking, processing, and modification of the precursor to generate a mature pheromone are unclear. In Staphylococcus aureus, AgrD is the propeptide for an autoinducing peptide (AIP) pheromone that triggers the Agr cell density-sensing system upon reaching a threshold and subsequently regulates expression of virulence factor genes. The transmembrane protein AgrB, encoded in the agr locus, is necessary for the processing of AgrD to produce mature AIP; however, it is not clear how AgrD interacts with AgrB and how this interaction results in the generation of mature AIP. In this study, we found that the AgrD propeptide was integrated into the cytoplasmic membrane by a conserved alpha-helical amphipathic motif in its N-terminal region. We demonstrated that membrane targeting of AgrD by this motif was required for the stabilization of AgrD and the production of mature AIP, although this region was not specifically involved in the interaction with AgrB. An artificial amphipathic peptide replacing the N-terminal amphipathic motif of AgrD directed the protein to the cytoplasmic membrane and enabled the production of AIP. Analysis of Bacillus ComX precursor protein sequences suggested that the amphipathic membrane-targeting motif might also exist in pheromone precursors of other Gram-positive bacteria.
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Affiliation(s)
- Linsheng Zhang
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
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50
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Fošnarič M, Kralj-Iglič V, Bohinc K, Iglič A, May S. Stabilization of Pores in Lipid Bilayers by Anisotropic Inclusions. J Phys Chem B 2003. [DOI: 10.1021/jp035035a] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Miha Fošnarič
- Laboratory of Applied Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia, Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Lipičeva 2, SI-1000 Ljubljana, Slovenia, and Institute of Molecular Biology, Friedrich-Schiller-University, Winzerlaer Strasse 10, Jena 07745, Germany
| | - Veronika Kralj-Iglič
- Laboratory of Applied Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia, Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Lipičeva 2, SI-1000 Ljubljana, Slovenia, and Institute of Molecular Biology, Friedrich-Schiller-University, Winzerlaer Strasse 10, Jena 07745, Germany
| | - Klemen Bohinc
- Laboratory of Applied Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia, Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Lipičeva 2, SI-1000 Ljubljana, Slovenia, and Institute of Molecular Biology, Friedrich-Schiller-University, Winzerlaer Strasse 10, Jena 07745, Germany
| | - Aleš Iglič
- Laboratory of Applied Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia, Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Lipičeva 2, SI-1000 Ljubljana, Slovenia, and Institute of Molecular Biology, Friedrich-Schiller-University, Winzerlaer Strasse 10, Jena 07745, Germany
| | - Sylvio May
- Laboratory of Applied Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia, Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Lipičeva 2, SI-1000 Ljubljana, Slovenia, and Institute of Molecular Biology, Friedrich-Schiller-University, Winzerlaer Strasse 10, Jena 07745, Germany
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