1
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Kumar H, Mandal S, Yadav R, Gupta S, Meena H, Kadu M, Kudawla R, Sharma P, Kaur IP, Maiti S, Ipsen JH, Bhatia T. Bottom-up approach to explore alpha-amylase assisted membrane remodelling. Chem Phys Lipids 2024; 259:105374. [PMID: 38176612 DOI: 10.1016/j.chemphyslip.2023.105374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/19/2023] [Accepted: 12/27/2023] [Indexed: 01/06/2024]
Abstract
Soluble alpha-amylases play an important role in the catabolism of polysaccharides. In this work, we show that the malt α -amylase can interact with the lipid membrane and further alter its mechanical properties. Vesicle fluctuation spectroscopy is used for quantitative measurement of the membrane bending rigidity of phosphatidylcholines lipid vesicles from the shape fluctuation based on the whole contour of Giant Unilamellar Vesicles (GUVs). The bending rigidity of the 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine lipid vesicles in water increases significantly with the presence of 0.14 micromolar alpha-amylase (AA) in the exterior solution. It appears that the enzyme present in the external solution interacts with the outer layer of the bilayer membrane, leading to an asymmetry of the solution on either side of the bilayer membrane and altering its elasticity. At AA concentration of 1.5 micromolars and above, changes in the morphology of the GUV membrane are observed. The interaction between AA in the external solution and the external leaflet causes the bilayer membrane to curve spontaneously, leading to the formation of outbuds, giving a positive spontaneous curvature of C0 ≤ 0.05 μm-1 at ≈ 1 mg / ml of the AA concentration. We validate and characterize its concentration-dependent role in stabilizing the membrane curvature. Our findings indicate that the involvement of the enzyme, depending on the concentration, can have a considerable effect on the mechanical characteristics of the membrane.
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Affiliation(s)
- Harshit Kumar
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, Manauli, SAS Nagar, Punjab 140306, India
| | - Sayar Mandal
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, Manauli, SAS Nagar, Punjab 140306, India
| | - Reena Yadav
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, Manauli, SAS Nagar, Punjab 140306, India
| | - Suhasi Gupta
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, Manauli, SAS Nagar, Punjab 140306, India
| | - Hemraj Meena
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, Manauli, SAS Nagar, Punjab 140306, India
| | - Mayur Kadu
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, Manauli, SAS Nagar, Punjab 140306, India
| | - Rajni Kudawla
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, Manauli, SAS Nagar, Punjab 140306, India
| | - Pratibha Sharma
- University Institute of Pharmaceutical Sciences, Punjab University, Sector 14, Chandigarh 160014, Punjab, India
| | - Indu Pal Kaur
- University Institute of Pharmaceutical Sciences, Punjab University, Sector 14, Chandigarh 160014, Punjab, India
| | - Subhabrata Maiti
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, Manauli, SAS Nagar, Punjab 140306, India
| | - John H Ipsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej, Odense, 5230 M, Denmark.
| | - Tripta Bhatia
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, Manauli, SAS Nagar, Punjab 140306, India.
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2
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Kondrashov OV, Akimov SA. Alteration of Average Thickness of Lipid Bilayer by Membrane-Deforming Inclusions. Biomolecules 2023; 13:1731. [PMID: 38136602 PMCID: PMC10741968 DOI: 10.3390/biom13121731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023] Open
Abstract
Thickness of lipid bilayer membranes is a key physical parameter determining membrane permeability and stability with respect to formation of through pores. Most membrane inclusions or impurities like amphipathic peptides, transmembrane peptides, lipid inclusions of a different molecular shape, lipid domains, and protein-lipid domains, locally deform the membrane. The detailed structure of the locally deformed region of the membrane is a kind of "fingerprint" for the inclusion type. However, most experimental methods allow determining only averaged parameters of membranes with incorporated inclusions, thus preventing the direct obtaining of the characteristics of the inclusion. Here we developed a model that allows the obtaining of characteristic parameters of three types of membrane inclusions (amphipathic peptides, transmembrane peptides, monolayer lipid patches) from experimentally observable dependencies of the average thickness of lipid bilayer on the surface concentration of the inclusions. In the case of amphipathic peptides, the model provided the peptide parameters that were in qualitative agreement with the available experimental data.
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Affiliation(s)
- Oleg V. Kondrashov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia
| | - Sergey A. Akimov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia
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3
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Karal MAS, Billah MM, Ahmed M, Ahamed MK. A review on the measurement of the bending rigidity of lipid membranes. SOFT MATTER 2023; 19:8285-8304. [PMID: 37873600 DOI: 10.1039/d3sm00882g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
This review provides an overview of the latest developments in both experimental and simulation techniques used to assess the bending rigidity of lipid membranes. It places special emphasis on experimental methods that utilize model vesicles to manipulate lipid compositions and other experimental parameters to determine the bending rigidity of the membrane. It also describes two commonly used simulation methods for estimating bending rigidity. The impact of various factors on membrane bending rigidity is summarized, including cholesterol, lipids, salt concentration, surface charge, membrane phase state, peptides, proteins, and polyethylene glycol. These factors are shown to influence the bending rigidity, contributing to a better understanding of the biophysical properties of membranes and their role in biological processes. Furthermore, the review discusses future directions and potential advancements in this research field, highlighting areas where further investigation is required.
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Affiliation(s)
- Mohammad Abu Sayem Karal
- Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh.
| | - Md Masum Billah
- Department of Physics, Jashore University of Science and Technology, Jashore 7408, Bangladesh
| | - Marzuk Ahmed
- Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
| | - Md Kabir Ahamed
- Radiation, Transport and Waste Safety Division, Bangladesh Atomic Energy Regulatory Authority, Agargaon, Dhaka 1207, Bangladesh
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4
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Pinigin KV, Akimov SA. The Membrane-Mediated Interaction of Liquid-Ordered Lipid Domains in the Presence of Amphipathic Peptides. MEMBRANES 2023; 13:816. [PMID: 37887988 PMCID: PMC10608175 DOI: 10.3390/membranes13100816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/08/2023] [Accepted: 09/22/2023] [Indexed: 10/28/2023]
Abstract
The lipid membranes of living cells are composed of a large number of lipid types and can undergo phase separation with the formation of nanometer-scale liquid-ordered lipid domains, also called rafts. Raft coalescence, i.e., the fusion of lipid domains, is involved in important cell processes, such as signaling and trafficking. In this work, within the framework of the theory of elasticity of lipid membranes, we explore how amphipathic peptides adsorbed on lipid membranes may affect the domain-domain fusion processes. We show that the elastic deformations of lipid membranes drive amphipathic peptides to the boundary of lipid domains, which leads to an increase in the average energy barrier of the domain-domain fusion, even if the surface concentration of amphipathic peptides is low and the domain boundaries are only partially occupied by the peptides. This inhibition of the fusion of lipid domains may lead to negative side effects of using amphipathic peptides as antimicrobial agents.
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Affiliation(s)
- Konstantin V. Pinigin
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia
| | - Sergey A. Akimov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia
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5
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Interaction of new VV-hemorphin-5 analogues with cell membrane models. Colloids Surf B Biointerfaces 2022; 220:112896. [DOI: 10.1016/j.colsurfb.2022.112896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 09/23/2022] [Accepted: 10/01/2022] [Indexed: 11/05/2022]
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6
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Marshall S, McGill B, Morcrette H, Winlove CP, Chimerel C, Petrov PG, Bokori-Brown M. Interaction of Clostridium perfringens Epsilon Toxin with the Plasma Membrane: The Role of Amino Acids Y42, Y43 and H162. Toxins (Basel) 2022; 14:toxins14110757. [PMID: 36356007 PMCID: PMC9694948 DOI: 10.3390/toxins14110757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/17/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022] Open
Abstract
Clostridium perfringens epsilon toxin (Etx) is a pore forming toxin that causes enterotoxaemia in ruminants and may be a cause of multiple sclerosis in humans. To date, most in vitro studies of Etx have used the Madin-Darby canine kidney (MDCK) cell line. However, studies using Chinese hamster ovary (CHO) cells engineered to express the putative Etx receptor, myelin and lymphocyte protein (MAL), suggest that amino acids important for Etx activity differ between species. In this study, we investigated the role of amino acids Y42, Y43 and H162, previously identified as important in Etx activity towards MDCK cells, in Etx activity towards CHO-human MAL (CHO-hMAL) cells, human red blood cells (hRBCs) and synthetic bilayers using site-directed mutants of Etx. We show that in CHO-hMAL cells Y42 is critical for Etx binding and not Y43 as in MDCK cells, indicating that surface exposed tyrosine residues in the receptor binding domain of Etx impact efficiency of cell binding to MAL-expressing cells in a species-specific manner. We also show that Etx mutant H162A was unable to lyse CHO-hMAL cells, lysed hRBCs, whilst it was able to form pores in synthetic bilayers, providing evidence of the complexity of Etx pore formation in different lipid environments.
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Affiliation(s)
- Skye Marshall
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
| | - Beth McGill
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
| | - Helen Morcrette
- College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - C. Peter Winlove
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
| | - Catalin Chimerel
- Automation Department, Faculty of Electrical Engineering and Computer Science, Transilvania University of Brasov, 500036 Brasov, Romania
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Peter G. Petrov
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
- Correspondence: (P.G.P.); (M.B.-B.); Tel.: +44-1392-724139 (P.G.P.)
| | - Monika Bokori-Brown
- College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
- Correspondence: (P.G.P.); (M.B.-B.); Tel.: +44-1392-724139 (P.G.P.)
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7
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Qian S, Zolnierczuk PA. Interaction of a Short Antimicrobial Peptide on Charged Lipid Bilayer: A Case Study on Aurein 1.2 Peptide. BBA ADVANCES 2022; 2:100045. [PMID: 37082600 PMCID: PMC10074906 DOI: 10.1016/j.bbadva.2022.100045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/21/2022] [Accepted: 02/01/2022] [Indexed: 12/27/2022] Open
Abstract
Aurein 1.2 (aurein) is a short but active α-helical antimicrobial peptide discovered in Australian tree frogs (Litoria aurea). It shows inhibition on a broad spectrum of bacteria and cancer cells. With well-defined helicity, amphipathicity, and cationic charges, it readily binds to membranes and causes membrane change and disruption. This study provides details on how aurein interacts with charged lipid membranes by using neutron membrane diffraction (NMD) and neutron spin echo (NSE) spectroscopy on complex peptide-membrane systems. NMD provides higher resolution lipid bilayer structures than solution scattering. NMD revealed the peptide is mostly associated in the lipid headgroup region. Even at moderately high concentrations (e.g., peptide:lipid ratio of 1:30), aurein is located at the acyl chain-headgroup region without deep penetration into the hydrophobic acyl chain. However, it does reduce the elasticity of the membrane at that concentration, which was corroborated by the NSE results. Furthermore, NSE shows that aurein first softens the membrane, like many other α-helical peptides at low concentration, but then makes the membrane much more rigid, even without membrane pore formation. Combining our previous studies, the evidence shows that aurein at relatively low concentrations still modifies lipid distribution significantly and can cause membrane thinning and lateral segregation of charged lipids. At the same time, the membrane's mechanical properties are modified with much slower lipid diffusion. This suggests that aurein can attack the microbial membrane without the need to form membrane pores or disintegrate membranes; instead, it promotes the formation of domains at low concentration.
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Affiliation(s)
- Shuo Qian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
- Second Target Station, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
- Corresponding author.
| | - Piotr A. Zolnierczuk
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
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8
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Kondrashov OV, Akimov SA. Regulation of Antimicrobial Peptide Activity via Tuning Deformation Fields by Membrane-Deforming Inclusions. Int J Mol Sci 2021; 23:ijms23010326. [PMID: 35008752 PMCID: PMC8745196 DOI: 10.3390/ijms23010326] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 12/22/2021] [Accepted: 12/28/2021] [Indexed: 01/10/2023] Open
Abstract
Antimicrobial peptides (AMPs) are considered prospective antibiotics. Some AMPs fight bacteria via cooperative formation of pores in their plasma membranes. Most AMPs at their working concentrations can induce lysis of eukaryotic cells as well. Gramicidin A (gA) is a peptide, the transmembrane dimers of which form cation-selective channels in membranes. It is highly toxic for mammalians as being majorly hydrophobic gA incorporates and induces leakage of both bacterial and eukaryotic cell membranes. Both pore-forming AMPs and gA deform the membrane. Here we suggest a possible way to reduce the working concentrations of AMPs at the expense of application of highly-selective amplifiers of AMP activity in target membranes. The amplifiers should alter the deformation fields in the membrane in a way favoring the membrane-permeabilizing states. We developed the statistical model that allows describing the effect of membrane-deforming inclusions on the equilibrium between AMP monomers and cooperative membrane-permeabilizing structures. On the example of gA monomer-dimer equilibrium, the model predicts that amphipathic peptides and short transmembrane peptides playing the role of the membrane-deforming inclusions, even in low concentration can substantially increase the lifetime and average number of gA channels.
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9
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Kondrashov OV, Rokitskaya TI, Batishchev OV, Kotova EA, Antonenko YN, Akimov SA. Peptide-induced membrane elastic deformations decelerate gramicidin dimer-monomer equilibration. Biophys J 2021; 120:5309-5321. [PMID: 34715080 DOI: 10.1016/j.bpj.2021.10.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 09/23/2021] [Accepted: 10/22/2021] [Indexed: 10/20/2022] Open
Abstract
Gramicidin A (gA) is a hydrophobic pentadecapeptide readily incorporating into a planar bilayer lipid membrane (BLM), thereby inducing a large macroscopic current across the BLM. This current results from ion-channel formation due to head-to-head transbilayer dimerization of gA monomers with rapidly established monomer-dimer equilibrium. Any disturbance of the equilibrium, e.g., by sensitized photoinactivation of a portion of gA monomers, causes relaxation toward a new equilibrium state. According to previous studies, the characteristic relaxation time of the gA-mediated electric current decreases as the current increases upon elevating the gA concentration in the membrane. Here, we report data on the current relaxation kinetics for gA analogs with N-terminal valine replaced by glycine or tyrosine. Surprisingly, the relaxation time increased rather than decreased upon elevation of the total membrane conductance induced by these gA analogs, thus contradicting the classical kinetic scheme. We developed a general theoretical model that accounts for lateral interaction of monomers and dimers mediated by membrane elastic deformations. The modified kinetic scheme of the gramicidin dimerization predicts the reverse dependence of the relaxation time on membrane conductance for gA analogs, with a decreased dimerization constant that is in a good agreement with our experimental data. The equilibration process may be also modulated by incorporation of other peptides ("impurities") into the lipid membrane.
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Affiliation(s)
- Oleg V Kondrashov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia
| | - Tatyana I Rokitskaya
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Oleg V Batishchev
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia
| | - Elena A Kotova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Yuri N Antonenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.
| | - Sergey A Akimov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia.
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10
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Ye S, Li W, Wang H, Zhu L, Wang C, Yang Y. Quantitative Nanomechanical Analysis of Small Extracellular Vesicles for Tumor Malignancy Indication. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100825. [PMID: 34338437 PMCID: PMC8456224 DOI: 10.1002/advs.202100825] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/31/2021] [Indexed: 05/27/2023]
Abstract
The nanomechanical properties of tumor-derived small extracellular vesicles (sEVs) are essential to cancer progression. Here, nanoindentation is utilized on atomic force microscopy (AFM) to quantitatively investigate the nanomechanical properties of human breast cancer cell-derived sEVs at single vesicle level and explore their relationship with tumor malignancy and vesicle size. It is demonstrated that the stiffness of the sEVs results from the combined contribution of the bending modulus and osmotic pressure of the sEVs. The stiffness and osmotic pressure increase with increasing malignancy of the sEVs and decrease with increasing size of the sEVs. The bending modulus decreases with increasing malignancy of the sEVs and is lower in smaller sEVs. This study builds relationship between the nanomechanical signature of the sEV and tumor malignancy, adding information for better understanding cancer mechanobiology.
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Affiliation(s)
- Siyuan Ye
- CAS Key Laboratory of Standardization and Measurement for NanotechnologyCAS Key Laboratory of Biological Effects of Nanomaterials and NanosafetyCAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
- Department of ChemistryTsinghua UniversityBeijing100084P. R. China
| | - Wenzhe Li
- CAS Key Laboratory of Standardization and Measurement for NanotechnologyCAS Key Laboratory of Biological Effects of Nanomaterials and NanosafetyCAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190P. R. China
- State Key Laboratory of Natural and Biomimetic DrugsSchool of Pharmaceutical SciencesPeking UniversityBeijing100871P. R. China
| | - Huayi Wang
- CAS Key Laboratory of Standardization and Measurement for NanotechnologyCAS Key Laboratory of Biological Effects of Nanomaterials and NanosafetyCAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
- Translational Medicine CenterChinese Institute for Brain Research (CIBR)Beijing102206P. R. China
| | - Ling Zhu
- CAS Key Laboratory of Standardization and Measurement for NanotechnologyCAS Key Laboratory of Biological Effects of Nanomaterials and NanosafetyCAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
| | - Chen Wang
- CAS Key Laboratory of Standardization and Measurement for NanotechnologyCAS Key Laboratory of Biological Effects of Nanomaterials and NanosafetyCAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
| | - Yanlian Yang
- CAS Key Laboratory of Standardization and Measurement for NanotechnologyCAS Key Laboratory of Biological Effects of Nanomaterials and NanosafetyCAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
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11
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Galassi VV, Wilke N. On the Coupling between Mechanical Properties and Electrostatics in Biological Membranes. MEMBRANES 2021; 11:478. [PMID: 34203412 PMCID: PMC8306103 DOI: 10.3390/membranes11070478] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/18/2021] [Accepted: 06/22/2021] [Indexed: 12/24/2022]
Abstract
Cell membrane structure is proposed as a lipid matrix with embedded proteins, and thus, their emerging mechanical and electrostatic properties are commanded by lipid behavior and their interconnection with the included and absorbed proteins, cytoskeleton, extracellular matrix and ionic media. Structures formed by lipids are soft, dynamic and viscoelastic, and their properties depend on the lipid composition and on the general conditions, such as temperature, pH, ionic strength and electrostatic potentials. The dielectric constant of the apolar region of the lipid bilayer contrasts with that of the polar region, which also differs from the aqueous milieu, and these changes happen in the nanometer scale. Besides, an important percentage of the lipids are anionic, and the rest are dipoles or higher multipoles, and the polar regions are highly hydrated, with these water molecules forming an active part of the membrane. Therefore, electric fields (both, internal and external) affects membrane thickness, density, tension and curvature, and conversely, mechanical deformations modify membrane electrostatics. As a consequence, interfacial electrostatics appears as a highly important parameter, affecting the membrane properties in general and mechanical features in particular. In this review we focus on the electromechanical behavior of lipid and cell membranes, the physicochemical origin and the biological implications, with emphasis in signal propagation in nerve cells.
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Affiliation(s)
- Vanesa Viviana Galassi
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza M5500, Argentina;
- Instituto Interdisciplinario de Ciencias Básicas (ICB), Universidad Nacional de Cuyo, CONICET, Mendoza M5500, Argentina
| | - Natalia Wilke
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba X5000HUA, Argentina
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Universidad Nacional de Córdoba, CONICET, Córdoba X5000HUA, Argentina
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12
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Kelley EG, Butler PD, Nagao M. Collective dynamics in lipid membranes containing transmembrane peptides. SOFT MATTER 2021; 17:5671-5681. [PMID: 33942045 PMCID: PMC10466476 DOI: 10.1039/d1sm00314c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Biological membranes are composed of complex mixtures of lipids and proteins that influence each other's structure and function. The biological activities of many channel-forming peptides and proteins are known to depend on the material properties of the surrounding lipid bilayer. However, less is known about how membrane-spanning channels affect the lipid bilayer properties, and in particular, their collective fluctuation dynamics. Here we use neutron spin echo spectroscopy (NSE) to measure the collective bending and thickness fluctuation dynamics in dimyristoylphosphatidylcholine (di 14 : 0 PC, DMPC) lipid membranes containing two different antimicrobial peptides, alamethicin (Ala) and gramicidin (gD). Ala and gD are both well-studied antimicrobial peptides that form oligomeric membrane-spanning channels with different structures. At low concentrations, the peptides did not have a measurable effect on the average bilayer structure, yet significantly changed the collective membrane dynamics. Despite both peptides forming transmembrane channels, they had opposite effects on the relaxation time of the collective bending fluctuations and associated effective bending modulus, where gD addition stiffened the membrane while Ala addition softened the membrane. Meanwhile, the lowest gD concentrations enhanced the collective thickness fluctuation dynamics, while the higher gD concentrations and all studied Ala concentrations dampened these dynamics. The results highlight the synergy between lipids and proteins in determining the collective membrane dynamics and that not all peptides can be universally treated as rigid bodies when considering their effects on the lipid bilayer fluctuations.
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Affiliation(s)
- Elizabeth G Kelley
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA.
| | - Paul D Butler
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA. and Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, USA and Department of Chemistry, The University of Tennessee Knoxville, TN 37996, USA
| | - Michihiro Nagao
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA. and Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA and Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA
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13
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Alvares DS, Monti MR, Ruggiero Neto J, Wilke N. The antimicrobial peptide Polybia-MP1 differentiates membranes with the hopanoid, diplopterol from those with cholesterol. BBA ADVANCES 2021; 1:100002. [PMID: 37082019 PMCID: PMC10074923 DOI: 10.1016/j.bbadva.2021.100002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Polybia-MP1 is an antimicrobial peptide that shows a decreased activity in membranes with cholesterol (CHO). Since it is now accepted that hopanoids act as sterol-surrogates in some sterol-lacking bacteria, we here inquire about the impact of Polybia-MP1 on membranes containing the hopanoid diplopterol (DP) in comparison to membranes with CHO. We found that, despite the properties induced on lipid membranes by DP are similar to those induced by CHO, the effect of Polybia-MP1 on membranes with CHO or DP was significantly different. DP did not prevent dye release from LUVs, nor the insertion of Polybia-MP1 into monolayers, and peptide-membrane affinity was higher for those with DP than with CHO. Zeta potentials ( ζ ) for DP-containing LUVs showed a complex behavior at increasing peptide concentration. The effect of the peptide on membrane elasticity, investigated by nanotube retraction experiments, showed that peptide addition softened all membrane compositions, but membranes with DP got stiffer at long times. Considering this, and the ζ results, we propose that peptides accumulate at the interface adopting different arrangements, leading to a non-monotonic behavior. Possible correlations with cell membranes were inquired testing the antimicrobial activity of Polybia-MP1 against hopanoid-lacking bacteria pre-incubated with DP or CHO. The fraction of surviving cells was lower in cultures incubated with DP compared to those incubated with CHO. We propose that the higher activity of Polybia-MP1 against some bacteria compared to mammalian cells is not only related to membrane electrostatics, but also the composition of neutral lipids, particularly the hopanoids, could be important.
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14
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Affiliation(s)
- Chandra Has
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India
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15
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Kondrashov OV, Galimzyanov TR, Molotkovsky RJ, Batishchev OV, Akimov SA. Membrane-Mediated Lateral Interactions Regulate the Lifetime of Gramicidin Channels. MEMBRANES 2020; 10:membranes10120368. [PMID: 33255806 PMCID: PMC7760706 DOI: 10.3390/membranes10120368] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 11/22/2020] [Accepted: 11/24/2020] [Indexed: 11/16/2022]
Abstract
The lipid matrix of cellular membranes is an elastic liquid crystalline medium. Its deformations regulate the functionality and interactions of membrane proteins,f membrane-bound peptides, lipid and protein-lipid domains. Gramicidin A (gA) is a peptide, which incorporates into membrane leaflets as a monomer and may form a transmembrane dimer. In both configurations, gA deforms the membrane. The transmembrane dimer of gA is a cation-selective ion channel. Its electrical response strongly depends on the elastic properties of the membrane. The gA monomer and dimer deform the membrane differently; therefore, the elastic energy contributes to the activation barriers of the dimerization and dissociation of the conducting state. It is shown experimentally that channel characteristics alter if gA molecules have been located in the vicinity of the conducting dimer. Here, based on the theory of elasticity of lipid membranes, we developed a quantitative theoretical model which allows explaining experimentally observed phenomena under conditions of high surface density of gA or its analogues, i.e., in the regime of strong lateral interactions of gA molecules, mediated by elastic deformations of the membrane. The model would be useful for the analysis and prediction of the gA electrical response in various experimental conditions. This potentially widens the possible applications of gA as a convenient molecular sensor of membrane elasticity.
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Affiliation(s)
- Oleg V. Kondrashov
- Correspondence: (O.V.K.); (S.A.A.); Tel.: +7-495-955-4776 (O.V.K.); +7-495-955-4776 (S.A.A.)
| | | | | | | | - Sergey A. Akimov
- Correspondence: (O.V.K.); (S.A.A.); Tel.: +7-495-955-4776 (O.V.K.); +7-495-955-4776 (S.A.A.)
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16
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Pinigin KV, Kuzmin PI, Akimov SA, Galimzyanov TR. Additional contributions to elastic energy of lipid membranes: Tilt-curvature coupling and curvature gradient. Phys Rev E 2020; 102:042406. [PMID: 33212684 DOI: 10.1103/physreve.102.042406] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 09/09/2020] [Indexed: 11/07/2022]
Abstract
Lipid bilayer membranes under biologically relevant conditions are flexible thin laterally fluid films consisting of two unimolecular layers (monolayers) each about 2 nm thick. On spatial scales much larger than the bilayer thickness, the membrane elasticity is well determined by its shape. The classical Helfrich theory considers the membrane as an elastic two-dimensional (2D) film, which has no particular internal structure. However, various local membrane heterogeneities can result in a lipids tilt relative to the membrane surface normal. On the basis of the classical elasticity theory of 3D bodies, Hamm and Kozlov [Eur. Phys. J. E 3, 323 (2000)10.1007/s101890070003] derived the most general energy functional, taking into account the tilt and lipid monolayer curvature. Recently, Terzi and Deserno [J. Chem. Phys. 147, 084702 (2017)10.1063/1.4990404] showed that Hamm and Kozlov's derivation was incomplete because the tilt-curvature coupling term had been missed. However, the energy functional derived by Terzi and Deserno appeared to be unstable, thereby being invalid for applications that require minimizations of the overall energy of deformations. Here, we derive a stable elastic energy functional, showing that the squared gradient of the curvature was missed in both of these works. This change in the energy functional arises from a more accurate consideration of the transverse shear deformation terms and their influence on the membrane stability. We also consider the influence of the prestress terms on the stability of the energy functional, and we show that it should be considered small and the effective Gaussian curvature should be neglected because of the stability requirements. We further generalize the theory, including the stretching-compressing deformation modes, and we provide the geometrical interpretation of the terms that were previously missed by Hamm and Kozlov. The physical consequences of the new terms are analyzed in the case of a membrane-mediated interaction of two amphipathic peptides located in the same monolayer. We also provide the expression for director fluctuations, comparing it with that obtained by Terzi and Deserno.
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Affiliation(s)
- Konstantin V Pinigin
- A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy prospekt, Moscow 119071, Russia
| | - Peter I Kuzmin
- A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy prospekt, Moscow 119071, Russia
| | - Sergey A Akimov
- A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy prospekt, Moscow 119071, Russia
| | - Timur R Galimzyanov
- A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy prospekt, Moscow 119071, Russia
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17
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Vitkova V, Mitkova D, Yordanova V, Pohl P, Bakowsky U, Staneva G, Batishchev O. Elasticity and phase behaviour of biomimetic membrane systems containing tetraether archaeal lipids. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.124974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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18
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Mirtaheri E, Dolatmoradi A, El-Zahab B. Thermally Assisted Acoustofluidic Separation Based on Membrane Protein Content. Anal Chem 2019; 91:13953-13961. [PMID: 31590489 DOI: 10.1021/acs.analchem.9b03485] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The over- and under-expression of certain proteins in extracellular vesicles has been observed in many physiological and pathological conditions; however, a simple method to sort vesicles based on contrast in protein content is yet to be developed. We herein present a nonaffinity-based method for rapid and inexpensive isolation of lipid vesicles based on their membrane protein content. Based on a composition-specific thermophysical property change of vesicles at different protein contents, an acoustic property change that enabled an acoustophoretic separation was observed. This change was demonstrated in a thermally modulated acoustofluidic device in the form of a shift in vesicle migration from the nodal plane to antinodal plane at a specific temperature known as the acoustic contrast temperature (TΦ). Using phosphatidylcholine vesicles containing the membrane proteins gramicidin D, alamethicin, and melittin at molar contents ranging from 0.001% to 10%, we observed that increasing the membrane protein content brought about conformational changes in the membrane which afforded the vesicles distinctive acoustic properties. Then, by establishing an acoustic contrast temperature window, vesicles with the same protein but different molar content were successfully separated. The efficiency of the separation was studied for various vesicle mixtures and a separation efficiency as high as 97% was accomplished. In order to confirm the technique's applicability for biological samples, sheep red blood cells with various melittin peptide contents similarly demonstrated the depressing effects of melittin on membrane bending modulus and depressed the TΦ of the cells. This method holds promise for a myriad of applications in the biomedical field, especially in bioanalytical research.
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Affiliation(s)
- Elnaz Mirtaheri
- Department of Mechanical and Materials Engineering , Florida International University , Miami , Florida 33174 , United States
| | - Ata Dolatmoradi
- Department of Mechanical and Materials Engineering , Florida International University , Miami , Florida 33174 , United States.,Department of Bioengineering and Therapeutic Sciences , University of California, San Francisco , San Francisco , California 94158 , United States
| | - Bilal El-Zahab
- Department of Mechanical and Materials Engineering , Florida International University , Miami , Florida 33174 , United States
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19
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Interaction of a Polyarginine Peptide with Membranes of Different Mechanical Properties. Biomolecules 2019; 9:biom9100625. [PMID: 31635304 PMCID: PMC6843195 DOI: 10.3390/biom9100625] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/15/2019] [Accepted: 10/17/2019] [Indexed: 01/18/2023] Open
Abstract
The membrane translocation efficiency of cell penetrating peptides (CPPs) has been largely studied, and poly-arginines have been highlighted as particularly active CPPs, especially upon negatively charged membranes. Here we inquire about the influence of membrane mechanical properties in poly-arginine adsorption, penetration and translocation, as well as the subsequent effect on the host membrane. For this, we selected anionic membranes exhibiting different rigidity and fluidity, and exposed them to the nona-arginine KR9C. Three different membrane compositions were investigated, all of them having 50% of the anionic lipid 1,2-dioleoyl-sn-glycero-3-phospho-(1’-rac-glycerol) (DOPG), thus, ensuring a high affinity of the peptide for membrane surfaces. The remaining 50% was a saturated PC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC), an unsaturated PC (1,2-dioleoyl-sn-glycero-3-phosphocholine, DOPC) or a mixture of DOPC with cholesterol. Peptide-membrane interactions were studied using four complementary models for membranes: Langmuir monolayers, Large Unilamellar Vesicles, Black Lipid Membranes and Giant Unilamellar Vesicles. The patterns of interaction of KR9C varied within the different membrane compositions. The peptide strongly adsorbed on membranes with cholesterol, but did not incorporate or translocate them. KR9C stabilized phase segregation in DPPC/DOPG films and promoted vesicle rupture. DOPC/DOPG appeared like the better host for peptide translocation: KR9C adsorbed, inserted and translocated these membranes without breaking them, despite softening was observed.
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20
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Mescola A, Marín-Medina N, Ragazzini G, Accolla M, Alessandrini A. Magainin-H2 effects on the permeabilization and mechanical properties of giant unilamellar vesicles. J Colloid Interface Sci 2019; 553:247-258. [PMID: 31207545 DOI: 10.1016/j.jcis.2019.06.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/28/2019] [Accepted: 06/09/2019] [Indexed: 10/26/2022]
Abstract
Among the potential novel therapeutics to treat bacterial infections, antimicrobial peptides (AMPs) are a very promising substitute due to their broad-spectrum activity and rapid bactericidal action. AMPs strongly interact with the bacterial membrane, and the need to have a correct understanding of the interaction between AMPs and lipid bilayers at a molecular level prompted a wealth of experimental and theoretical studies exploiting a variety of AMPs. Here, we studied the effects of magainin H2 (Mag H2), an analog of the well-known magainin 2 (wt Mag 2) AMP endowed with a higher degree of hydrophobicity, on giant unilamellar vesicles (GUVs) concentrating on its permeabilization activity and the effect on the lipid bilayer mechanical properties. We demonstrated that the increased hydrophobicity of Mag H2 affects its selectivity conferring a strong permeabilization activity also on zwitterionic lipid bilayers. Moreover, when lipid mixtures including PG lipids are considered, PG has a protective effect, at variance from wt Mag 2, suggesting that for Mag H2 the monolayer curvature could prevail over the peptide-membrane electrostatic interaction. We then mechanically characterized GUVs by measuring the effect of Mag H2 on the bending constant of lipid bilayers by flickering spectroscopy and, by using micropipette aspiration technique, we followed the steps leading to vesicle permeabilization. We found that Mag H2, notwithstanding its enhanced hydrophobicity, has a pore formation mechanism compatible with the toroidal pore model similar to that of wt Mag 2.
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Affiliation(s)
- Andrea Mescola
- CNR-Nanoscience Institute-S3, Via Campi 213/A, 41125 Modena, Italy.
| | - Nathaly Marín-Medina
- Department of Physics, University of Los Andes, Carrera 1 N° 18A - 12, Bogotá, Colombia.
| | - Gregorio Ragazzini
- CNR-Nanoscience Institute-S3, Via Campi 213/A, 41125 Modena, Italy; Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Via Campi 213/A, 41125 Modena, Italy.
| | - Maurizio Accolla
- Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Via Campi 213/A, 41125 Modena, Italy
| | - Andrea Alessandrini
- CNR-Nanoscience Institute-S3, Via Campi 213/A, 41125 Modena, Italy; Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Via Campi 213/A, 41125 Modena, Italy.
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21
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The helix-to-sheet transition of an HIV-1 fusion peptide derivative changes the mechanical properties of lipid bilayer membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:565-572. [DOI: 10.1016/j.bbamem.2018.12.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 12/06/2018] [Accepted: 12/07/2018] [Indexed: 11/18/2022]
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22
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Siaw HMH, Raghunath G, Dyer RB. Peripheral Protein Unfolding Drives Membrane Bending. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:8400-8407. [PMID: 29925237 PMCID: PMC6069603 DOI: 10.1021/acs.langmuir.8b01136] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Dynamic modulation of lipid membrane curvature can be achieved by a number of peripheral protein binding mechanisms such as hydrophobic insertion of amphipathic helices and membrane scaffolding. Recently, an alternative mechanism was proposed in which crowding of peripherally bound proteins induces membrane curvature through steric pressure generated by lateral collisions. This effect was enhanced using intrinsically disordered proteins that possess high hydrodynamic radii, prompting us to explore whether membrane bending can be triggered by the folding-unfolding transition of surface-bound proteins. We utilized histidine-tagged human serum albumin bound to Ni-NTA-DGS containing liposomes as our model system to test this hypothesis. We found that reduction of the disulfide bonds in the protein resulted in unfolding of HSA, which subsequently led to membrane tubule formation. The frequency of tubule formation was found to be significantly higher when the proteins were unfolded while being localized to a phase-separated domain as opposed to randomly distributed in fluid phase liposomes, indicating that the steric pressure generated from protein unfolding can drive membrane deformation. Our results are critical for the design of peripheral membrane protein-immobilization strategies and open new avenues for exploring mechanisms of membrane bending driven by conformational changes of peripheral membrane proteins.
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23
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Grasso G, Muscat S, Rebella M, Morbiducci U, Audenino A, Danani A, Deriu MA. Cell penetrating peptide modulation of membrane biomechanics by Molecular dynamics. J Biomech 2018; 73:137-144. [PMID: 29631749 DOI: 10.1016/j.jbiomech.2018.03.036] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 03/14/2018] [Accepted: 03/21/2018] [Indexed: 11/17/2022]
Abstract
The efficacy of a pharmaceutical treatment is often countered by the inadequate membrane permeability, that prevents drugs from reaching their specific intracellular targets. Cell penetrating peptides (CPPs) are able to route across cells' membrane various types of cargo, including drugs and nanoparticles. However, CPPs internalization mechanisms are not yet fully understood and depend on a wide variety of aspects. In this contest, the entry of a CPP into the lipid bilayer might induce molecular conformational changes, including marked variations on membrane's mechanical properties. Understanding how the CPP does influence the mechanical properties of cells membrane is crucial to design, engineer and improve new and existing penetrating peptides. Here, all atom Molecular Dynamics (MD) simulations were used to investigate the interaction between different types of CPPs embedded in a lipid bilayer of dioleoyl phosphatidylcholine (DOPC). In a greater detail, we systematically highlighted how CPP properties are responsible for modulating the membrane bending modulus. Our findings highlighted the CPP hydropathy strongly correlated with penetration of water molecules in the lipid bilayer, thus supporting the hypothesis that the amount of water each CPP can route inside the membrane is modulated by the hydrophobic and hydrophilic character of the peptide. Water penetration promoted by CPPs leads to a local decrease of the lipid order, which emerges macroscopically as a reduction of the membrane bending modulus.
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Affiliation(s)
- Gianvito Grasso
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale (IDSIA), Scuola universitaria professionale della Svizzera italiana (SUPSI), Università della Svizzera Italiana (USI), Centro Galleria 2, Manno CH-6928, Switzerland
| | - Stefano Muscat
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10128 Torino, Italy
| | - Martina Rebella
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10128 Torino, Italy
| | - Umberto Morbiducci
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10128 Torino, Italy
| | - Alberto Audenino
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10128 Torino, Italy
| | - Andrea Danani
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale (IDSIA), Scuola universitaria professionale della Svizzera italiana (SUPSI), Università della Svizzera Italiana (USI), Centro Galleria 2, Manno CH-6928, Switzerland
| | - Marco A Deriu
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale (IDSIA), Scuola universitaria professionale della Svizzera italiana (SUPSI), Università della Svizzera Italiana (USI), Centro Galleria 2, Manno CH-6928, Switzerland.
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24
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Silva T, Claro B, Silva BFB, Vale N, Gomes P, Gomes MS, Funari SS, Teixeira J, Uhríková D, Bastos M. Unravelling a Mechanism of Action for a Cecropin A-Melittin Hybrid Antimicrobial Peptide: The Induced Formation of Multilamellar Lipid Stacks. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:2158-2170. [PMID: 29304549 DOI: 10.1021/acs.langmuir.7b03639] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An understanding of the mechanism of action of antimicrobial peptides is fundamental to the development of new and more active antibiotics. In the present work, we use a wide range of techniques (SANS, SAXD, DSC, ITC, CD, and confocal and electron microscopy) in order to fully characterize the interaction of a cecropin A-melittin hybrid antimicrobial peptide, CA(1-7)M(2-9), of known antimicrobial activity, with a bacterial model membrane of POPE/POPG in an effort to unravel its mechanism of action. We found that CA(1-7)M(2-9) disrupts the vesicles, inducing membrane condensation and forming an onionlike structure of multilamellar stacks, held together by the intercalated peptides. SANS and SAXD revealed changes induced by the peptide in the lipid bilayer thickness and the bilayer stiffening in a tightly packed liquid-crystalline lamellar phase. The analysis of the observed abrupt changes in the repeat distance upon the phase transition to the gel state suggests the formation of an Lγ phase. To the extent of our knowledge, this is the first time that the Lγ phase is identified as part of the mechanism of action of antimicrobial peptides. The energetics of interaction depends on temperature, and ITC results indicate that CA(1-7)M(2-9) interacts with the outer leaflet. This further supports the idea of a surface interaction that leads to membrane condensation and not to pore formation. As a result, we propose that this peptide exerts its antimicrobial action against bacteria through extensive membrane disruption that leads to cell death.
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Affiliation(s)
- Tânia Silva
- CIQ-UP - Centro de Investigação em Química, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto , 4169-007 Porto, Portugal
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto , 4200-135 Porto, Portugal
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto , 4150-171 Porto, Portugal
- ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto , 4050-313 Porto, Portugal
| | - Bárbara Claro
- CIQ-UP - Centro de Investigação em Química, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto , 4169-007 Porto, Portugal
| | - Bruno F B Silva
- INL - International Iberian Nanotechnology Laboratory , 4715-330 Braga, Portugal
| | - Nuno Vale
- UCIBIO/REQUIMTE, Laboratório de Farmacologia, Departamento de Ciências do Medicamento, Faculdade de Farmácia, Universidade do Porto , 4050-313 Porto, Portugal
| | - Paula Gomes
- LAQV/REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto , 4169-007 Porto, Portugal
| | - Maria Salomé Gomes
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto , 4200-135 Porto, Portugal
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto , 4150-171 Porto, Portugal
- ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto , 4050-313 Porto, Portugal
| | | | - José Teixeira
- Laboratoire Léon Brillouin (CEA-CNRS) , CEA Saclay, 91191 Gif sur Yvette Cedex, France
| | - Daniela Uhríková
- Faculty of Pharmacy, Comenius University in Bratislava , 832 32 Bratislava, Slovak Republic
| | - Margarida Bastos
- CIQ-UP - Centro de Investigação em Química, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto , 4169-007 Porto, Portugal
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25
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Pan J, Sahoo PK, Dalzini A, Hayati Z, Aryal CM, Teng P, Cai J, Gutierrez HR, Song L. Membrane Disruption Mechanism of a Prion Peptide (106-126) Investigated by Atomic Force Microscopy, Raman and Electron Paramagnetic Resonance Spectroscopy. J Phys Chem B 2017; 121:5058-5071. [PMID: 28459565 PMCID: PMC5770145 DOI: 10.1021/acs.jpcb.7b02772] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A fragment of the human prion protein spanning residues 106-126 (PrP106-126) recapitulates many essential properties of the disease-causing protein such as amyloidogenicity and cytotoxicity. PrP106-126 has an amphipathic characteristic that resembles many antimicrobial peptides (AMPs). Therefore, the toxic effect of PrP106-126 could arise from a direct association of monomeric peptides with the membrane matrix. Several experimental approaches are employed to scrutinize the impacts of monomeric PrP106-126 on model lipid membranes. Porous defects in planar bilayers are observed by using solution atomic force microscopy. Adding cholesterol does not impede defect formation. A force spectroscopy experiment shows that PrP106-126 reduces Young's modulus of planar lipid bilayers. We use Raman microspectroscopy to study the effect of PrP106-126 on lipid atomic vibrational dynamics. For phosphatidylcholine lipids, PrP106-126 disorders the intrachain conformation, while the interchain interaction is not altered; for phosphatidylethanolamine lipids, PrP106-126 increases the interchain interaction, while the intrachain conformational order remains similar. We explain the observed differences by considering different modes of peptide insertion. Finally, electron paramagnetic resonance spectroscopy shows that PrP106-126 progressively decreases the orientational order of lipid acyl chains in magnetically aligned bicelles. Together, our experimental data support the proposition that monomeric PrP106-126 can disrupt lipid membranes by using similar mechanisms found in AMPs.
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Affiliation(s)
- Jianjun Pan
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Prasana K. Sahoo
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Annalisa Dalzini
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Zahra Hayati
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Chinta M. Aryal
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Peng Teng
- Department of Chemistry, University of South Florida, Tampa, Florida 33620, United States
| | - Jianfeng Cai
- Department of Chemistry, University of South Florida, Tampa, Florida 33620, United States
| | | | - Likai Song
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
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26
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Khadka NK, Teng P, Cai J, Pan J. Modulation of lipid membrane structural and mechanical properties by a peptidomimetic derived from reduced amide scaffold. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:734-744. [PMID: 28132901 DOI: 10.1016/j.bbamem.2017.01.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 01/22/2017] [Accepted: 01/25/2017] [Indexed: 10/20/2022]
Abstract
Understanding how antimicrobial peptidomimetics interact with lipid membranes is important in battling multidrug resistant bacterial pathogens. We study the effects of a recently reported peptidomimetic on lipid bilayer structural and mechanical properties. The compound referred to as E107-3 is synthesized based on the acylated reduced amide scaffold and has been shown to exhibit good antimicrobial potency. Our vesicle leakage assay indicates that the compound increases lipid bilayer permeability. We use micropipette aspiration to explore the kinetic response of giant unilamellar vesicles (GUVs). Exposure to the compound causes the GUV protrusion length LP to spontaneously increase and then decrease, followed by GUV rupture. Solution atomic force microscopy (AFM) is used to visualize lipid bilayer structural modulation within a nanoscopic regime. Unlike melittin, which produces pore-like structures, the peptidomimetic compound is found to induce nanoscopic heterogeneous structures. Finally, we use AFM-based force spectroscopy to study the impact of the compound on lipid bilayer mechanical properties. We find that incremental addition of the compound to planar lipid bilayers results in a moderate decrease of the bilayer puncture force FP and a 39% decrease of the bilayer area compressibility modulus KA. To explain our experimental data, we propose a membrane interaction model encompassing disruption of lipid chain packing and extraction of lipid molecules. The later action mode is supported by our observation of a double-bilayer structure in the presence of fusogenic calcium ions.
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Affiliation(s)
- Nawal K Khadka
- Department of Physics, University of South Florida, Tampa, FL 33620, United States
| | - Peng Teng
- Department of Chemistry, University of South Florida, Tampa, FL 33620, United States
| | - Jianfeng Cai
- Department of Chemistry, University of South Florida, Tampa, FL 33620, United States
| | - Jianjun Pan
- Department of Physics, University of South Florida, Tampa, FL 33620, United States.
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27
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Rigid proteins and softening of biological membranes-with application to HIV-induced cell membrane softening. Sci Rep 2016; 6:25412. [PMID: 27149877 PMCID: PMC4858729 DOI: 10.1038/srep25412] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 04/14/2016] [Indexed: 11/15/2022] Open
Abstract
A key step in the HIV-infection process is the fusion of the virion membrane with the target cell membrane and the concomitant transfer of the viral RNA. Experimental evidence suggests that the fusion is preceded by considerable elastic softening of the cell membranes due to the insertion of fusion peptide in the membrane. What are the mechanisms underpinning the elastic softening of the membrane upon peptide insertion? A broader question may be posed: insertion of rigid proteins in soft membranes ought to stiffen the membranes not soften them. However, experimental observations perplexingly appear to show that rigid proteins may either soften or harden membranes even though conventional wisdom only suggests stiffening. In this work, we argue that regarding proteins as merely non-specific rigid inclusions is flawed, and each protein has a unique mechanical signature dictated by its specific interfacial coupling to the surrounding membrane. Predicated on this hypothesis, we have carried out atomistic simulations to investigate peptide-membrane interactions. Together with a continuum model, we reconcile contrasting experimental data in the literature including the case of HIV-fusion peptide induced softening. We conclude that the structural rearrangements of the lipids around the inclusions cause the softening or stiffening of the biological membranes.
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Karamdad K, Law RV, Seddon JM, Brooks NJ, Ces O. Preparation and mechanical characterisation of giant unilamellar vesicles by a microfluidic method. LAB ON A CHIP 2015; 15:557-62. [PMID: 25413588 DOI: 10.1039/c4lc01277a] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Giant unilamellar vesicles (GUVs) have a wide range of applications in biology and synthetic biology. As a result, new approaches for constructing GUVs using microfluidic techniques are emerging but there are still significant shortcomings in the control of fundamental vesicle structural parameters such as size, lamellarity, membrane composition and internal contents. We have developed a novel microfluidic platform to generate compositionally-controlled GUVs. Water-in-oil (W/O) droplets formed in a lipid-containing oil flow are transferred across an oil-water interface, facilitating the self-assembly of a phospholipid bilayer. In addition, for the first time we have studied the mechanical properties of the resultant lipid bilayers of the microfluidic GUVs. Using fluctuation analysis we were able to calculate the values for bending rigidity of giant vesicles assembled on chip and demonstrate that these correlate strongly with those of traditional low throughput strategies such as electroformation.
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Affiliation(s)
- K Karamdad
- Department of Chemistry, Imperial College London, Exhibition Road, London, SW7 2AZ, UK.
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29
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Pott T, Gerbeaud C, Barbier N, Méléard P. Melittin modifies bending elasticity in an unexpected way. Chem Phys Lipids 2015; 185:99-108. [DOI: 10.1016/j.chemphyslip.2014.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 04/28/2014] [Accepted: 05/18/2014] [Indexed: 12/22/2022]
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30
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Garten M, Prévost C, Cadart C, Gautier R, Bousset L, Melki R, Bassereau P, Vanni S. Methyl-branched lipids promote the membrane adsorption of α-synuclein by enhancing shallow lipid-packing defects. Phys Chem Chem Phys 2015; 17:15589-97. [DOI: 10.1039/c5cp00244c] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reconstitution experiments on Giant Unilamellar Vesicles and Molecular Dynamics Simulations indicate that alpha-synuclein binds to neutral flat membranes in the presence of methyl-branched lipids.
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Affiliation(s)
| | | | | | - Romain Gautier
- Institut de Pharmacologie Moléculaire et Cellulaire
- Université de Nice Sophia-Antipolis and Centre National de la Recherche Scientifique
- UMR 7275
- 06560 Valbonne
- France
| | - Luc Bousset
- CNRS
- Paris Saclay Institute of Neuroscience
- Gif-sur-Yvette
- France
| | - Ronald Melki
- CNRS
- Paris Saclay Institute of Neuroscience
- Gif-sur-Yvette
- France
| | | | - Stefano Vanni
- Institut de Pharmacologie Moléculaire et Cellulaire
- Université de Nice Sophia-Antipolis and Centre National de la Recherche Scientifique
- UMR 7275
- 06560 Valbonne
- France
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31
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Vitkova V, Mitkova D, Staneva G. Lyso- and omega-3-containing phosphatidylcholines alter the bending elasticity of lipid membranes. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2014.03.055] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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32
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Dimova R. Recent developments in the field of bending rigidity measurements on membranes. Adv Colloid Interface Sci 2014; 208:225-34. [PMID: 24666592 DOI: 10.1016/j.cis.2014.03.003] [Citation(s) in RCA: 307] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 02/28/2014] [Accepted: 03/02/2014] [Indexed: 12/19/2022]
Abstract
This review gives a brief overview of experimental approaches used to assess the bending rigidity of membranes. Emphasis is placed on techniques based on the use of giant unilamellar vesicles. We summarize the effect on the bending rigidity of membranes as a function of membrane composition, presence of various inclusions in the bilayer and molecules and ions in the bathing solutions. Examples for the impact of temperature, cholesterol, some peptides and proteins, sugars and salts are provided and the literature data are discussed critically. Future directions, open questions and possible developments in this research field are also included.
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Affiliation(s)
- Rumiana Dimova
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany.
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33
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Rahaman A, Lazaridis T. A thermodynamic approach to alamethicin pore formation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014. [DOI: 10.1016/j.bbamem.2014.01.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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34
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Rahaman A, Lazaridis T. A thermodynamic approach to alamethicin pore formation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:98-105. [PMID: 24071593 DOI: 10.1016/j.bbamem.2013.09.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 09/10/2013] [Accepted: 09/17/2013] [Indexed: 12/15/2022]
Abstract
The structure and energetics of alamethicin Rf30 monomer to nonamer in cylindrical pores of 5 to 11Å radius are investigated using molecular dynamics simulations in an implicit membrane model that includes the free energy cost of acyl chain hydrophobic area exposure. Stable, low energy pores are obtained for certain combinations of radius and oligomeric number. The trimer and the tetramer formed 6Å pores that appear closed while the larger oligomers formed open pores at their optimal radius. The hexamer in an 8Å pore and the octamer in an 11Å pore give the lowest effective energy per monomer. However, all oligomers beyond the pentamer have comparable energies, consistent with the observation of multiple conductance levels. The results are consistent with the widely accepted "barrel-stave" model. The N terminal portion of the molecule exhibits smaller tilt with respect to the membrane normal than the C terminal portion, resulting in a pore shape that is a hybrid between a funnel and an hourglass. Transmembrane voltage has little effect on the structure of the oligomers but enhances or decreases their stability depending on its orientation. Antiparallel bundles are lower in energy than the commonly accepted parallel ones and could be present under certain experimental conditions. Dry aggregates (without an aqueous pore) have lower average effective energy than the corresponding aggregates in a pore, suggesting that alamethicin pores may be excited states that are stabilized in part by voltage and in part by the ion flow itself.
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Affiliation(s)
- Asif Rahaman
- Department of Chemistry, City College of New York, 160 Convent Avenue, New York, NY 10031, USA
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35
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Coupling Membrane Elasticity and Structure to Protein Function. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/b978-0-12-411515-6.00004-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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36
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Charged Lipid Bilayers in Aqueous Surroundings with Low pH. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/b978-0-12-411515-6.00001-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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37
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Overview of a Quest for Bending Elasticity Measurement. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/b978-0-12-411516-3.00003-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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38
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39
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40
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Bruno MJ, Rusinova R, Gleason NJ, Koeppe RE, Andersen OS. Interactions of drugs and amphiphiles with membranes: modulation of lipid bilayer elastic properties by changes in acyl chain unsaturation and protonation. Faraday Discuss 2013; 161:461-80; discussion 563-89. [PMID: 23805753 PMCID: PMC3703894 DOI: 10.1039/c2fd20092a] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
Poly-unsaturated fatty acids (PUFAs) alter the function of many membrane proteins, whereas monounsatured fatty acids generally are inert. We previously showed that docosahexaenoic acid (DHA) at pH 7 decreases the bilayer stiffness, consistent with an amphiphile-induced increase in elasticity, but not with a negative change in curvature; oleic acid (OA) was inert (Bruno, Koeppe and Andersen, Proc. Natl. Acad. Sci., 2007, 104, 9638-9643). To further explore how PUFAs and other amphiphiles may alter lipid bilayer properties, and thus membrane protein function, we examined how changes in acyl chain unsaturation and head group charge and size alter bilayer properties, as sensed by bilayer-spanning gramicidin A (gA) channels of different lengths. Compared to DHA, the neutral DHA-methyl ester has reduced effects on bilayer properties and 1-palmitoyl-2-docosahexaenoyl-phosphatidylcholine (PDPC) forms bilayers that are softer than dioleoylphosphatidylcholine (DOPC). The changes in channel function are larger for the short gA channels, indicating that changes in elasticity dominate over changes in curvature. We altered the fatty acid protonation by titration: docosahexaenoic acid (DHA) is more potent at pH 9 (relative to pH 7) and is inert at pH 4; OA, which was inert at pH 7, becomes a potent modifier of bilayer properties at pH 9. At both pH 7 and 9, DHA and OA produced larger changes in the lifetimes of the short gA channels, demonstrating that they increase lipid bilayer elasticity when deprotonated--though OA promotes the formation of inverted hexagonal phases at pH 7. The positively charged oleylamine (OAm), which has a small head-group and therefore should be a negative curvature promoter, inhibited gA channel function with similar reductions in the lifetimes of the short and long gA channels, indicating a curvature-dominated effect. Monitoring the single-channel conductance, we find that the negatively charged fatty acids increase the conductance by increasing the local negative charge around the channel, whereas the positively charged OAm has no effect. These results suggest that deprotonated fatty acids increase bilayer elasticity by reversibly adsorbing at the bilayer/solution interface.
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Affiliation(s)
- Michael J. Bruno
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York 10065, USA
- Department of Chemistry, Guilford College, Greensboro, NC 27410, USA
| | - Radda Rusinova
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York 10065, USA
| | - Nicholas J. Gleason
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Roger E. Koeppe
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Olaf S. Andersen
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York 10065, USA
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41
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Bending Rigidities of Lipid Bilayers. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/b978-0-12-396533-2.00006-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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42
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Settles EI, Loftus AF, McKeown AN, Parthasarathy R. The vesicle trafficking protein Sar1 lowers lipid membrane rigidity. Biophys J 2010; 99:1539-45. [PMID: 20816066 PMCID: PMC2931751 DOI: 10.1016/j.bpj.2010.06.059] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 06/16/2010] [Accepted: 06/29/2010] [Indexed: 02/04/2023] Open
Abstract
The sculpting of membranes into dynamic, curved shapes is central to intracellular cargo trafficking. Though the generation of membrane curvature during trafficking necessarily involves both lipids and membrane-associated proteins, current mechanistic views focus primarily on the formation of rigid cages and curved scaffolds by protein assemblies. Here we report on a different mechanism for the control of membrane deformation, unrelated to the imposition of predefined curvature, involving modulation of membrane material properties: Sar1, a GTPase that regulates vesicle trafficking from the endoplasmic reticulum, lowers the rigidity of the lipid bilayer membrane to which it binds. In vitro assays in which optically trapped microspheres create controlled membrane deformations revealed a monotonic decline in bending modulus as a function of Sar1 concentration, down to nearly zero rigidity, indicating a dramatic lowering of the energetic cost of curvature generation. This is the first demonstration that a vesicle trafficking protein lowers the rigidity of its target membrane, leading to a new conceptual framework for vesicle biogenesis.
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Affiliation(s)
| | | | | | - Raghuveer Parthasarathy
- Department of Physics, University of Oregon, Eugene, Oregon
- Department of Materials Science Institute, University of Oregon, Eugene, Oregon
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43
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Lee JH, Choi SM, Doe C, Faraone A, Pincus PA, Kline SR. Thermal fluctuation and elasticity of lipid vesicles interacting with pore-forming peptides. PHYSICAL REVIEW LETTERS 2010; 105:038101. [PMID: 20867811 DOI: 10.1103/physrevlett.105.038101] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Indexed: 05/08/2023]
Abstract
The thermal fluctuation and elasticity of dioleoyl-phosphocholine large unilamellar vesicle interacting with pore-forming peptide, melittin, were investigated by neutron spin-echo measurements. The relaxation behavior of the membrane fluctuation with different peptide to lipid molar ratio P/L can be divided into three regions, resulting from characteristic changes of the effective bending modulus κ(˜) of the membrane which includes the effects of internal dissipation within the membrane. At low P/L, melittin is adsorbed parallel to the surface of membrane and κ(˜) decreases significantly due to perturbation of hydrocarbon chain packing. At a critical P/L, melittin forms pores in the membrane and κ(˜) starts to increase slightly due to high pore rigidity. At higher P/L where the repulsive interpore interaction becomes significant, κ(˜) increases rapidly.
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Affiliation(s)
- Ji-Hwan Lee
- Department of Nuclear and Quantum Engineering, KAIST, Daejeon, 305-701, Republic of Korea
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44
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Impact of membrane-anchored fluorescent probes on the mechanical properties of lipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1333-7. [DOI: 10.1016/j.bbamem.2010.03.026] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 03/30/2010] [Accepted: 03/31/2010] [Indexed: 12/19/2022]
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45
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Pabst G, Kucerka N, Nieh MP, Rheinstädter MC, Katsaras J. Applications of neutron and X-ray scattering to the study of biologically relevant model membranes. Chem Phys Lipids 2010; 163:460-79. [PMID: 20361949 DOI: 10.1016/j.chemphyslip.2010.03.010] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 03/23/2010] [Accepted: 03/24/2010] [Indexed: 11/19/2022]
Abstract
Scattering techniques, in particular electron, neutron and X-ray scattering have played a major role in elucidating the static and dynamic structure of biologically relevant membranes. Importantly, neutron and X-ray scattering have evolved to address new sample preparations that better mimic biological membranes. In this review, we will report on some of the latest model membrane results, and the neutron and X-ray techniques that were used to obtain them.
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Affiliation(s)
- G Pabst
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, A-8042 Graz, Austria
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46
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Reister-Gottfried E, Leitenberger SM, Seifert U. Diffusing proteins on a fluctuating membrane: analytical theory and simulations. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:031903. [PMID: 20365766 DOI: 10.1103/physreve.81.031903] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Indexed: 05/29/2023]
Abstract
Using analytical calculations and computer simulations, we consider both the lateral diffusion of a membrane protein and the fluctuation spectrum of the membrane in which the protein is embedded. The membrane protein interacts with the membrane shape through its spontaneous curvature and bending rigidity. The lateral motion of the protein may be viewed as diffusion in an effective potential, hence, the effective mobility is always reduced compared to the case of free diffusion. Using a rigorous path-integral approach, we derive an analytical expression for the effective diffusion coefficient for small ratios of temperature and bending rigidity, which is the biologically relevant limit. Simulations show very good quantitative agreement with our analytical result. The analysis of the correlation functions contributing to the diffusion coefficient shows that the correlations between the stochastic force of the protein and the response in the membrane shape are responsible for the reduction. Our quantitative analysis of the membrane height correlation spectrum shows an influence of the protein-membrane interaction causing a distinctly altered wave-vector dependence compared to a free membrane. Furthermore, the time correlations exhibit the two relevant time scales of the system: that of membrane fluctuations and that of lateral protein diffusion with the latter typically much longer than the former. We argue that the analysis of the long-time decay of membrane height correlations can thus provide a new means to determine the effective diffusion coefficient of proteins in the membrane.
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47
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Alamethicin in lipid bilayers: combined use of X-ray scattering and MD simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1387-97. [PMID: 19248763 DOI: 10.1016/j.bbamem.2009.02.013] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Revised: 01/29/2009] [Accepted: 02/19/2009] [Indexed: 10/21/2022]
Abstract
We study fully hydrated bilayers of two di-monounsaturated phospholipids diC18:1PC (DOPC) and diC22:1PC with varying amounts of alamethicin (Alm). We combine the use of X-ray diffuse scattering and molecular dynamics simulations to determine the orientation of alamethicin in model lipids. Comparison of the experimental and simulated form factors shows that Alm helices are inserted transmembrane at high humidity and high concentrations, in agreement with earlier results. The X-ray scattering data and the MD simulations agree that membrane thickness changes very little up to 1/10 Alm/DOPC. In contrast, the X-ray data indicate that the thicker diC22:1PC membrane thins with added Alm, a total decrease in thickness of 4 A at 1/10 Alm/diC22:1PC. The different effect of Alm on the thickness changes of the two bilayers is consistent with Alm having a hydrophobic thickness close to the hydrophobic thickness of 27 A for DOPC; Alm is then mismatched with the 7 A thicker diC22:1PC bilayer. The X-ray data indicate that Alm decreases the bending modulus (K(C)) by a factor of approximately 2 in DOPC and a factor of approximately 10 in diC22:1PC membranes (P/L approximately 1/10). The van der Waals and fluctuational interactions between bilayers are also evaluated through determination of the anisotropic B compressibility modulus.
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48
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Méléard P, Bagatolli LA, Pott T. Giant unilamellar vesicle electroformation from lipid mixtures to native membranes under physiological conditions. Methods Enzymol 2009; 465:161-76. [PMID: 19913167 DOI: 10.1016/s0076-6879(09)65009-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Giant unilamellar vesicles (GUVs) are well-known model systems, especially because they are easily observable using optical microscopy. In this chapter, we revisit in detail the versatile GUV electroformation protocol. We demonstrate how GUV electroformation can be adapted to various membrane systems including synthetic lipid mixtures, natural lipid extracts, and bilayers containing membrane proteins. Further, we show how to adjust this protocol to a given aqueous environment and prove that GUVs can be obtained under physiologically relevant conditions, that is, in the presence of electrolytes. Finally, we provide firm evidence that electroformation is a method of choice to produce giant vesicles from native cell membranes. This is illustrated with the example of GUV electroformation from red blood cell ghosts in a physiologically pertinent buffer. GUVs obtained in this manner maintain the native membrane asymmetry, thereby validating the physiological relevance of GUV electroformation.
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49
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Softening of POPC membranes by magainin. Biophys Chem 2008; 137:7-12. [DOI: 10.1016/j.bpc.2008.06.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 06/02/2008] [Accepted: 06/02/2008] [Indexed: 11/22/2022]
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50
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Marsh D. Elastic curvature constants of lipid monolayers and bilayers. Chem Phys Lipids 2006; 144:146-59. [PMID: 17045578 DOI: 10.1016/j.chemphyslip.2006.08.004] [Citation(s) in RCA: 225] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 08/22/2006] [Accepted: 08/29/2006] [Indexed: 11/21/2022]
Abstract
Bending elasticity is an important property of lipid vesicles, non-lamellar lipid phases and biological membranes. Experimental values of the mean curvature moduli, k(c), of lipid bilayers and of the monolayer leaflets of inverted hexagonal (H(II)) phases of lipids are tabulated here for easy reference. Experimental estimates of the Gaussian curvature modulus, k (c), are also included. Consideration is given to the relation between the bending moduli of bilayers and the constituent monolayer leaflets. Useful mathematical relations involving the bending moduli and spontaneous curvature are summarized.
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Affiliation(s)
- Derek Marsh
- Max-Planck-Institut für biophysikalische Chemie, Dept. Spektroskopie, 37070 Göttingen, Germany.
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