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Ahyayauch H, Masserini ME, Alonso A, Goñi FM. Understanding Aβ Peptide Binding to Lipid Membranes: A Biophysical Perspective. Int J Mol Sci 2024; 25:6401. [PMID: 38928107 PMCID: PMC11203662 DOI: 10.3390/ijms25126401] [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: 04/27/2024] [Revised: 05/27/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024] Open
Abstract
Aβ peptides are known to bind neural plasma membranes in a process leading to the deposit of Aβ-enriched plaques. These extracellular structures are characteristic of Alzheimer's disease, the major cause of late-age dementia. The mechanisms of Aβ plaque formation and deposition are far from being understood. A vast number of studies in the literature describe the efforts to analyze those mechanisms using a variety of tools. The present review focuses on biophysical studies mostly carried out with model membranes or with computational tools. This review starts by describing basic physical aspects of lipid phases and commonly used model membranes (monolayers and bilayers). This is followed by a discussion of the biophysical techniques applied to these systems, mainly but not exclusively Langmuir monolayers, isothermal calorimetry, density-gradient ultracentrifugation, and molecular dynamics. The Methodological Section is followed by the core of the review, which includes a summary of important results obtained with each technique. The last section is devoted to an overall reflection and an effort to understand Aβ-bilayer binding. Concepts such as Aβ peptide membrane binding, adsorption, and insertion are defined and differentiated. The roles of membrane lipid order, nanodomain formation, and electrostatic forces in Aβ-membrane interaction are separately identified and discussed.
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Affiliation(s)
- Hasna Ahyayauch
- Departamento de Bioquímica, Instituto Biofisika (CSIC, UPV/EHU), Universidad del País Vasco, 48940 Leioa, Spain; (H.A.); (A.A.)
- Institut Supérieur des Professions Infirmières et Techniques de Santé, Rabat 60000, Morocco
- Laboratoire de Biologie et Santé, Unité Neurosciences, Neuroimmunologie et Comportement, Faculty of Sciences, Ibn Tofail University, Kénitra 14000, Morocco
| | - Massimo E. Masserini
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy;
| | - Alicia Alonso
- Departamento de Bioquímica, Instituto Biofisika (CSIC, UPV/EHU), Universidad del País Vasco, 48940 Leioa, Spain; (H.A.); (A.A.)
| | - Félix M. Goñi
- Departamento de Bioquímica, Instituto Biofisika (CSIC, UPV/EHU), Universidad del País Vasco, 48940 Leioa, Spain; (H.A.); (A.A.)
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Muñoz-Gutiérrez C, Adasme-Carreño F, Alzate-Morales J, Ireta J. Effect of strand register in the stability and reactivity of crystals from peptides forming amyloid fibrils. Phys Chem Chem Phys 2023; 25:23885-23893. [PMID: 37642522 DOI: 10.1039/d3cp01762a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Amyloids are cytotoxic protein aggregates that deposit in human tissues, leading to several health disorders. Their aggregates can also exhibit catalytic properties, and they have been used as candidates for the development of functional biomaterials. Despite being polymorphic, amyloids often assemble as cross-β fibrils formed by in-register β sheet layers. Recent studies of some amyloidogenic protein segments revealed that they crystallize as antiparallel out-of-register β sheets. Such arrangement has been proposed to be responsible for the cytotoxicity in amyloid diseases, however, there is still no consensus on the molecular mechanism. Interestingly, two amyloidogenic peptide segments, NFGAILS and FGAILSS, arrange into out-of-register and in-register β sheets, respectively, even though they solely differ by one aminoacid residue at both termini. In this work, we used density functional theory (DFT) to address how the strand register contributes into the packing and molecular properties of the NFGAILS and FGAILSS crystals. Our results show that the out-of-register structure is substantially more stable, at 0 K, than the in-register one due to stronger inter-strand contacts. Based on an analysis of the electrostatic potential of the crystal slabs, it is suggested that the out-of-register may potentially interact with negatively charged groups, like those found in cell membranes. Moreover, calculated reactivity descriptors indicate a similar outcome, where only the out-of-register peptide exhibits intrinsic reactive surface sites at the exposed amine and carboxylic groups. It is therefore suggested that the out-of-register arrangement may indeed be crucial for amyloid cytotoxicity. The findings presented here could help to further our understanding of amyloid aggregation, function, and toxicity.
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Affiliation(s)
- Camila Muñoz-Gutiérrez
- Centro de Bioinformática, Simulación y Modelado (CBSM), Facultad de Ingeniería, Universidad de Talca, Campus Talca, 1 Poniente No. 1141, Box 721, Talca, Chile
| | - Francisco Adasme-Carreño
- Centro de Investigación de Estudios Avanzados del Maule (CIEAM), Vicerrectoría de Investigación y Postgrado, Universidad Católica del Maule, Talca 3480112, Chile
- Laboratorio de Bioinformática y Química Computacional (LBQC), Departamento de Medicina Traslacional, Facultad de Medicina, Universidad Católica del Maule, Talca 3480112, Chile
| | - Jans Alzate-Morales
- Centro de Bioinformática, Simulación y Modelado (CBSM), Facultad de Ingeniería, Universidad de Talca, Campus Talca, 1 Poniente No. 1141, Box 721, Talca, Chile
| | - Joel Ireta
- Departamento de Química, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, A.P. 55-534, Ciudad de México 09340, Mexico.
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Adélaïde M, Salnikov E, Ramos-Martín F, Aisenbrey C, Sarazin C, Bechinger B, D’Amelio N. The Mechanism of Action of SAAP-148 Antimicrobial Peptide as Studied with NMR and Molecular Dynamics Simulations. Pharmaceutics 2023; 15:pharmaceutics15030761. [PMID: 36986623 PMCID: PMC10051583 DOI: 10.3390/pharmaceutics15030761] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 02/18/2023] [Accepted: 02/21/2023] [Indexed: 03/02/2023] Open
Abstract
Background: SAAP-148 is an antimicrobial peptide derived from LL-37. It exhibits excellent activity against drug-resistant bacteria and biofilms while resisting degradation in physiological conditions. Despite its optimal pharmacological properties, its mechanism of action at the molecular level has not been explored. Methods: The structural properties of SAAP-148 and its interaction with phospholipid membranes mimicking mammalian and bacterial cells were studied using liquid and solid-state NMR spectroscopy as well as molecular dynamics simulations. Results: SAAP-148 is partially structured in solution and stabilizes its helical conformation when interacting with DPC micelles. The orientation of the helix within the micelles was defined by paramagnetic relaxation enhancements and found similar to that obtained using solid-state NMR, where the tilt and pitch angles were determined based on 15N chemical shift in oriented models of bacterial membranes (POPE/POPG). Molecular dynamic simulations revealed that SAAP-148 approaches the bacterial membrane by forming salt bridges between lysine and arginine residues and lipid phosphate groups while interacting minimally with mammalian models containing POPC and cholesterol. Conclusions: SAAP-148 stabilizes its helical fold onto bacterial-like membranes, placing its helix axis almost perpendicular to the surface normal, thus probably acting by a carpet-like mechanism on the bacterial membrane rather than forming well-defined pores.
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Affiliation(s)
- Morgane Adélaïde
- Unité de Génie Enzymatique et Cellulaire UMR 7025 CNRS, Université de Picardie Jules Verne, 80039 Amiens, France
| | - Evgeniy Salnikov
- Institut de Chimie, UMR7177, Université de Strasbourg/CNRS, 67000 Strasbourg, France
| | - Francisco Ramos-Martín
- Unité de Génie Enzymatique et Cellulaire UMR 7025 CNRS, Université de Picardie Jules Verne, 80039 Amiens, France
- Correspondence: (F.R.-M.); (N.D.); Tel.: +33-3-22-82-74-73 (F.R.-M. & N.D.)
| | - Christopher Aisenbrey
- Institut de Chimie, UMR7177, Université de Strasbourg/CNRS, 67000 Strasbourg, France
| | - Catherine Sarazin
- Unité de Génie Enzymatique et Cellulaire UMR 7025 CNRS, Université de Picardie Jules Verne, 80039 Amiens, France
| | - Burkhard Bechinger
- Institut de Chimie, UMR7177, Université de Strasbourg/CNRS, 67000 Strasbourg, France
| | - Nicola D’Amelio
- Unité de Génie Enzymatique et Cellulaire UMR 7025 CNRS, Université de Picardie Jules Verne, 80039 Amiens, France
- Correspondence: (F.R.-M.); (N.D.); Tel.: +33-3-22-82-74-73 (F.R.-M. & N.D.)
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Molecular Dynamics Simulation Studies on the Aggregation of Amyloid-β Peptides and Their Disaggregation by Ultrasonic Wave and Infrared Laser Irradiation. Molecules 2022; 27:molecules27082483. [PMID: 35458686 PMCID: PMC9030874 DOI: 10.3390/molecules27082483] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 03/29/2022] [Accepted: 04/07/2022] [Indexed: 01/02/2023] Open
Abstract
Alzheimer’s disease is understood to be caused by amyloid fibrils and oligomers formed by aggregated amyloid-β (Aβ) peptides. This review article presents molecular dynamics (MD) simulation studies of Aβ peptides and Aβ fragments on their aggregation, aggregation inhibition, amyloid fibril conformations in equilibrium, and disruption of the amyloid fibril by ultrasonic wave and infrared laser irradiation. In the aggregation of Aβ, a β-hairpin structure promotes the formation of intermolecular β-sheet structures. Aβ peptides tend to exist at hydrophilic/hydrophobic interfaces and form more β-hairpin structures than in bulk water. These facts are the reasons why the aggregation is accelerated at the interface. We also explain how polyphenols, which are attracting attention as aggregation inhibitors of Aβ peptides, interact with Aβ. An MD simulation study of the Aβ amyloid fibrils in equilibrium is also presented: the Aβ amyloid fibril has a different structure at one end from that at the other end. The amyloid fibrils can be destroyed by ultrasonic wave and infrared laser irradiation. The molecular mechanisms of these amyloid fibril disruptions are also explained, particularly focusing on the function of water molecules. Finally, we discuss the prospects for developing treatments for Alzheimer’s disease using MD simulations.
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Press-Sandler O, Miller Y. Molecular insights into the primary nucleation of polymorphic amyloid β dimers in DOPC lipid bilayer membrane. Protein Sci 2022; 31:e4283. [PMID: 35129859 PMCID: PMC8994488 DOI: 10.1002/pro.4283] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/01/2022] [Accepted: 02/03/2022] [Indexed: 11/29/2022]
Abstract
Alzheimer's disease (AD) pathology is characterized by loss of memory cognitive and behavioral deterioration. One of the hallmarks of AD is amyloid β (Aβ) plaques in the brain that consists of Aβ oligomers and fibrils. It is accepted that oligomers, particularly dimers, are toxic species that are produced extracellularly and intracellularly in membranes. It is believed that the disruption of membranes by polymorphic Aβ oligomers is the key for the pathology of AD. This is a first study that investigate the effect of polymorphic “α‐helix/random coil” and “fibril‐like” Aβ dimers on 1,2‐dioleoyl‐sn‐glycero‐3‐phosphocholine (DOPC) membrane. It has been found that the DOPC membrane promotes Aβ1–42 “fibril‐like” dimers and impedes Aβ1–42 “α‐helix/random coil” dimers. The N‐termini domains within Aβ1–42 dimers play a role in Aβ aggregation in membrane milieus. In addition, the aromatic π–π interactions (involving residues F19 and F20 in Aβ1–42) are the driving forces for the hydrophobic interactions that initiate the primary nucleation of polymorphic Aβ1–42 dimers within DOPC membrane. Finally, the DOPC bilayer membrane thickness is locally decreased, and it is disrupted by an embedded distinct Aβ1–42 dimer, due to relatively large contacts between Aβ1–42 monomers and the DOPC membrane. This study reveals insights into the molecular mechanisms by which polymorphic early‐stage Aβ1–42 dimers have distinct impacts on DOPC membrane.
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Affiliation(s)
- Olga Press-Sandler
- Department of Chemistry, Ben-Gurion University of the Negev, P.O. Box 653, Be'er Sheva, Israel.,Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beér-Sheva, Israel
| | - Yifat Miller
- Department of Chemistry, Ben-Gurion University of the Negev, P.O. Box 653, Be'er Sheva, Israel.,Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beér-Sheva, Israel
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Sahoo A, Matysiak S. Effects of applied surface-tension on membrane-assisted Aβ aggregation. Phys Chem Chem Phys 2021; 23:20627-20633. [PMID: 34514475 DOI: 10.1039/d1cp02642a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Accumulation of protein-based (Aβ) aggregates on cellular membranes with varying structural properties is commonly recognized as the key step in Alzheimer's pathogenesis. But experimental and computational challenges have made this biophysical characterization difficult. In particular, studies connecting biological membrane organization and Aβ aggregation are limited. While experiments have suggested that an increased membrane curvature results in faster Aβ peptide aggregation in the context of Alzheimer's disease, a mechanistic explanation for this relation is missing. In this work, we are leveraging molecular simulations with a physics-based coarse grained model to address and understand the relationships between curved cellular membranes and aggregation of a model template peptide Aβ 16-22. In agreement with experimental results, our simulations also suggest a positive correlation between increased peptide aggregation and membrane curvature. More curved membranes have higher lipid packing defects that engage peptide hydrophobic groups and promote faster diffusion leading to peptide fibrillar structures. In addition, we curated the effects of peptide aggregation on the membrane's structure and organization. Interfacial peptide aggregation results in heterogeneous headgroup-peptide interactions and an induced crowding effect at the lipid headgroup region, leading to a more ordered headgroup region and disordered lipid-tails at the membrane core. This work presents a mechanistic and morphological overview of the relationships between the biomembrane local structure and organization, and Aβ peptide aggregation.
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Affiliation(s)
- Abhilash Sahoo
- Biophysics Program, Institute of Physical Science and Technology, University of Maryland, College Park, MD, USA
| | - Silvina Matysiak
- Biophysics Program, Institute of Physical Science and Technology, University of Maryland, College Park, MD, USA.,Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA.
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Yang Y, Jalali S, Nilsson BL, Dias CL. Binding Mechanisms of Amyloid-like Peptides to Lipid Bilayers and Effects of Divalent Cations. ACS Chem Neurosci 2021; 12:2027-2035. [PMID: 33973758 DOI: 10.1021/acschemneuro.1c00140] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
In several neurodegenerative diseases, cell toxicity can emerge from damage produced by amyloid aggregates to lipid membranes. The details accounting for this damage are poorly understood including how individual amyloid peptides interact with phospholipid membranes before aggregation. Here, we use all-atom molecular dynamics simulations to investigate the molecular mechanisms accounting for amyloid-membrane interactions and the role played by calcium ions in this interaction. Model peptides known to self-assemble into amyloid fibrils and bilayer made from zwitterionic and anionic lipids are used in this study. We find that both electrostatic and hydrophobic interactions contribute to peptide-bilayer binding. In particular, the attraction of peptides to lipid bilayers is dominated by electrostatic interactions between positive residues and negative phosphate moieties of lipid head groups. This attraction is stronger for anionic bilayers than for zwitterionic ones. Hydrophobicity drives the burial of nonpolar residues into the interior of the bilayer producing strong binding in our simulations. Moreover, we observe that the attraction of peptides to the bilayer is significantly reduced in the presence of calcium ions. This is due to the binding of calcium ions to negative phosphate moieties of lipid head groups, which leaves phospholipid bilayers with a net positive charge. Strong binding of the peptide to the membrane occurs less frequently in the presence of calcium ions and involves the formation of a "Ca2+ bridge".
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Affiliation(s)
- Yanxing Yang
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102-1982, United States
| | - Sharareh Jalali
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102-1982, United States
| | - Bradley L. Nilsson
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Cristiano L. Dias
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102-1982, United States
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Li Y, Tang H, Andrikopoulos N, Javed I, Cecchetto L, Nandakumar A, Kakinen A, Davis TP, Ding F, Ke PC. The membrane axis of Alzheimer's nanomedicine. ADVANCED NANOBIOMED RESEARCH 2021; 1:2000040. [PMID: 33748816 PMCID: PMC7971452 DOI: 10.1002/anbr.202000040] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Alzheimer's disease (AD) is a major neurological disorder impairing its carrier's cognitive function, memory and lifespan. While the development of AD nanomedicine is still nascent, the field is evolving into a new scientific frontier driven by the diverse physicochemical properties and theranostic potential of nanomaterials and nanocomposites. Characteristic to the AD pathology is the deposition of amyloid plaques and tangles of amyloid beta (Aβ) and tau, whose aggregation kinetics may be curbed by nanoparticle inhibitors via sequence-specific targeting or nonspecific interactions with the amyloidogenic proteins. As literature implicates cell membrane as a culprit in AD pathogenesis, here we summarize the membrane axis of AD nanomedicine and present a new rationale that the field development may greatly benefit from harnessing our existing knowledge of Aβ-membrane interaction, nanoparticle-membrane interaction and Aβ-nanoparticle interaction.
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Affiliation(s)
- Yuhuan Li
- Zhongshan Hospital, Fudan University, 111 Yixueyuan Rd, Xuhui District, Shanghai, 200032, China
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Huayuan Tang
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
| | - Nicholas Andrikopoulos
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Ibrahim Javed
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Luca Cecchetto
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- Department of Chemical and Pharmaceutical Science, University of Trieste, Via Licio Giorgieri 1, 34127 Trieste, Italy
| | - Aparna Nandakumar
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Aleksandr Kakinen
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Thomas P. Davis
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Feng Ding
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
| | - Pu Chun Ke
- Zhongshan Hospital, Fudan University, 111 Yixueyuan Rd, Xuhui District, Shanghai, 200032, China
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
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Ermilova I, Lyubartsev AP. Modelling of interactions between Aβ(25-35) peptide and phospholipid bilayers: effects of cholesterol and lipid saturation. RSC Adv 2020; 10:3902-3915. [PMID: 35492630 PMCID: PMC9048594 DOI: 10.1039/c9ra06424a] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 12/14/2019] [Indexed: 11/25/2022] Open
Abstract
Aggregation of amyloid beta (Aβ) peptides in neuronal membranes is a known promoter of Alzheimer’s disease. To gain insight into the molecular details of Aβ peptide aggregation and its effect on model neuronal membranes, we carried out molecular dynamics simulations of the Aβ(25–35) fragment of the amyloid precursor protein in phospholipid bilayers composed of either fully saturated or highly unsaturated lipids, in the presence or absence of cholesterol. It was found that the peptide does not penetrate through any of the considered membranes, but can reside in the headgroup region and upper part of the lipid tails showing a clear preference to a polyunsaturated cholesterol-free membrane. Due to the ordering and condensing effect upon addition of cholesterol, membranes become more rigid facilitating peptide aggregation on the surface. Except for the case of the cholesterol-free saturated lipid bilayer, the peptides have a small effect on the membrane structure and ordering. It was also found that the most “active” amino-acid for peptide–lipid and peptide–cholesterol interaction is methionine-35, followed by asparagine-27 and serine-26, which form hydrogen bonds between peptides and polar atoms of lipid headgroups. These amino acids are also primarily responsible for peptide aggregation. This work will be relevant for designing strategies to develop drugs to combat Alzheimer’s disease. Molecular dynamics simulations of Aβ(25–35) peptides in phospholipid bilayers are carried out to investigate the effect of polyunsaturated lipids and cholesterol on aggregation of the peptides. ![]()
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Affiliation(s)
- Inna Ermilova
- Department of Materials and Environmental Chemistry, Stockholm University Stockholm Sweden +46 8161193
| | - Alexander P Lyubartsev
- Department of Materials and Environmental Chemistry, Stockholm University Stockholm Sweden +46 8161193
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Computational studies of protein aggregation mediated by amyloid: Fibril elongation and secondary nucleation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 170:461-504. [DOI: 10.1016/bs.pmbts.2019.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Dongmo Foumthuim CJ, Corazza A, Esposito G, Fogolari F. Molecular dynamics simulations of β2-microglobulin interaction with hydrophobic surfaces. MOLECULAR BIOSYSTEMS 2018; 13:2625-2637. [PMID: 29051937 DOI: 10.1039/c7mb00464h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hydrophobic surfaces are known to adsorb and unfold proteins, a process that has been studied only for a few proteins. Here we address the interaction of β2-microglobulin, a paradigmatic protein for the study of amyloidogenesis, with hydrophobic surfaces. A system with 27 copies of the protein surrounded by a model cubic hydrophobic box is studied by implicit solvent molecular dynamics simulations. Most proteins adsorb on the walls of the box without major distortions in local geometry, whereas free molecules maintain proper structures and fluctuations as observed in explicit solvent molecular dynamics simulations. The major conclusions from the simulations are as follows: (i) the adopted implicit solvent model is adequate to describe protein dynamics and thermodynamics; (ii) adsorption occurs readily and is irreversible on the simulated timescale; (iii) the regions most involved in molecular encounters and stable interactions with the walls are the same as those that are important in protein-protein and protein-nanoparticle interactions; (iv) unfolding following adsorption occurs at regions found to be flexible by both experiments and simulations; (v) thermodynamic analysis suggests a very large contribution from van der Waals interactions, whereas unfavorable electrostatic interactions are not found to contribute much to adsorption energy. Surfaces with different degrees of hydrophobicity may occur in vivo. Our simulations show that adsorption is a fast and irreversible process which is accompanied by partial unfolding. The results and the thermodynamic analysis presented here are consistent with and rationalize previous experimental work.
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Owen MC, Kulig W, Poojari C, Rog T, Strodel B. Physiologically-relevant levels of sphingomyelin, but not GM1, induces a β-sheet-rich structure in the amyloid-β(1-42) monomer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1709-1720. [PMID: 29626441 DOI: 10.1016/j.bbamem.2018.03.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/29/2018] [Accepted: 03/31/2018] [Indexed: 01/07/2023]
Abstract
To resolve the contribution of ceramide-containing lipids to the aggregation of the amyloid-β protein into β-sheet rich toxic oligomers, we employed molecular dynamics simulations to study the effect of cholesterol-containing bilayers comprised of POPC (70% POPC, and 30% cholesterol) and physiologically relevant concentrations of sphingomyelin (SM) (30% SM, 40% POPC, and 30% cholesterol), and the GM1 ganglioside (5% GM1, 70% POPC, and 25% cholesterol). The increased bilayer rigidity provided by SM (and to a lesser degree, GM1) reduced the interactions between the SM-enriched bilayer and the N-terminus of Aβ42 (and also residues Ser26, Asn27, and Lys28), which facilitated the formation of a β-sheet in the normally disordered N-terminal region. Aβ42 remained anchored to the SM-enriched bilayer through hydrogen bonds with the side chain of Arg5. With β-sheets in the at the N and C termini, the structure of Aβ42 in the sphingomyelin-enriched bilayer most resembles β-sheet-rich structures found in higher-ordered Aβ fibrils. Conversely, when bound to a bilayer comprised of 5% GM1, the conformation remained similar to that observed in the absence of GM1, with Aβ42 only making contact with one or two GM1 molecules. This article is part of a Special Issue entitled: Protein Aggregation and Misfolding at the Cell Membrane Interface edited by Ayyalusamy Ramamoorthy.
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Affiliation(s)
- Michael C Owen
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany; CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno 625 00, Czech Republic.
| | - Waldemar Kulig
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland; Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland
| | - Chetan Poojari
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland; Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland
| | - Tomasz Rog
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland; Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany; Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany.
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Role of the cell membrane interface in modulating production and uptake of Alzheimer's beta amyloid protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1639-1651. [PMID: 29572033 DOI: 10.1016/j.bbamem.2018.03.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/13/2018] [Accepted: 03/14/2018] [Indexed: 12/22/2022]
Abstract
The beta amyloid protein (Aβ) plays a central role in Alzheimer's disease (AD) pathogenesis and its interaction with cell membranes in known to promote mutually disruptive structural perturbations that contribute to amyloid deposition and neurodegeneration in the brain. In addition to protein aggregation at the membrane interface and disruption of membrane integrity, growing reports demonstrate an important role for the membrane in modulating Aβ production and uptake into cells. The aim of this review is to highlight and summarize recent literature that have contributed insight into the implications of altered membrane composition on amyloid precursor protein (APP) proteolysis, production of Aβ, its internalization in to cells via permeabilization and receptor mediated uptake. Here, we also review the various membrane model systems and experimental tools used for probing Aβ-membrane interactions to investigate the key mechanistic aspects underlying the accumulation and toxicity of Aβ in AD.
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Liu Y, Ren B, Zhang Y, Sun Y, Chang Y, Liang G, Xu L, Zheng J. Molecular simulation aspects of amyloid peptides at membrane interface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1906-1916. [PMID: 29421626 DOI: 10.1016/j.bbamem.2018.02.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 12/13/2022]
Abstract
The interactions of amyloid peptides with cell membranes play an important role in maintaining the integrity and functionality of cell membrane. A thorough molecular-level understanding of the structure, dynamics, and interactions between amyloid peptides and cell membranes is critical to amyloid aggregation and toxicity mechanisms for the bench-to-bedside applications. Here we review the most recent computational studies of amyloid peptides at model cell membranes. Different mechanisms of action of amyloid peptides on/in cell membranes, targeted by different computational techniques at different lengthscales and timescales, are rationally discussed. Finally, we have proposed some new insights into the remaining challenges and perspectives for future studies to improve our understanding of the activity of amyloid peptides associated with protein-misfolding diseases. This article is part of a Special Issue entitled: Protein Aggregation and Misfolding at the Cell Membrane Interface edited by Ayyalusamy Ramamoorthy.
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Affiliation(s)
- Yonglan Liu
- Hunan Key Laboratory of Biomedical Nanomaterials and Devices, College of Life Science and Chemistry, Hunan University of Technology, Zhuzhou 412007, PR China; Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States
| | - Baiping Ren
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States
| | - Yanxian Zhang
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States
| | - Yan Sun
- Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Yung Chang
- R&D Center for Membrane Technology and Department of Chemical EngineeringChung Yuan Christian University, Chung-Li, Taoyuan 320, Taiwan
| | - Guizhao Liang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044, PR China
| | - Lijian Xu
- Hunan Key Laboratory of Biomedical Nanomaterials and Devices, College of Life Science and Chemistry, Hunan University of Technology, Zhuzhou 412007, PR China; Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States.
| | - Jie Zheng
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States.
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15
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Jafari M, Mehrnejad F, Doustdar F. Insight into the interactions, residue snorkeling, and membrane disordering potency of a single antimicrobial peptide into different lipid bilayers. PLoS One 2017; 12:e0187216. [PMID: 29125878 PMCID: PMC5695277 DOI: 10.1371/journal.pone.0187216] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/16/2017] [Indexed: 12/30/2022] Open
Abstract
Pardaxin, with a bend-helix-bend-helix structure, is a membrane-active antimicrobial peptide that its membrane activity depends on the lipid bilayer composition. Herein, all-atom molecular dynamics (MD) simulations were performed to provide further molecular insight into the interactions, structural dynamics, orientation behavior, and cationic residues snorkeling of pardaxin in the DMPC, DPPC, POPC, POPG, POPG/POPE (3:1), and POPG/POPE (1:3) lipid bilayers. The results showed that the C-terminal helix of the peptide was maintained in all six types of the model-bilayers and pardaxin was tilted into the DMPC, DPPC, and POPG/POPE mixed bilayers more than the POPC and POPG bilayers. As well as, the structure of zwitterionic membranes was more affected by the peptide than the anionic bilayers. Taken together, the study demonstrated that the cationic residues of pardaxin snorkeled toward the interface of lipid bilayers and all phenylalanine residues of the peptide played important roles in the peptide-membrane interactions. We hope that this work will provide a better understanding of the interactions of antimicrobial peptides with the membranes.
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Affiliation(s)
- Majid Jafari
- Department of Life Sciences Engineering, Faculty of New Sciences & Technologies, University of Tehran, Tehran, Iran
| | - Faramarz Mehrnejad
- Department of Life Sciences Engineering, Faculty of New Sciences & Technologies, University of Tehran, Tehran, Iran
| | - Farahnoosh Doustdar
- Department of Microbiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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16
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Fu Y, Yan T, Xu X. Insight of Transmembrane Processes of Self-Assembling Nanotubes Based on a Cyclic Peptide Using Coarse Grained Molecular Dynamics Simulation. J Phys Chem B 2017; 121:9006-9012. [PMID: 28872323 DOI: 10.1021/acs.jpcb.7b05948] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Transmembrane self-assembling cyclic peptide (SCP) nanotubes are promising candidates for delivering specific molecules through cell membranes. The detailed mechanisms behind the transmembrane processes, as well as stabilization factors of transmembrane structures, are difficult to elucidate through experiments. In this study, the effects of peptide sequence and oligomeric state on the transmembrane capabilities of SCP nanotubes and the perturbation of embedded SCP nanotubes acting on the membrane were investigated based on coarse grained molecular dynamics simulation. The simulation results reveal that hydrophilic SCP oligomers result in the elevation of the energy barrier while the oligomerization of hydrophobic SCPs causes the reduction of the energy barrier, further leading to membrane insertion. Once SCP nanotubes are embedded, membrane properties such as density, thickness, ordering state and lateral mobility are adjusted along the radial direction. This study provides insight into the transmembrane strategy of SCP nanotubes and sheds light on designing novel transport systems.
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Affiliation(s)
- Yankai Fu
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences , Beijing 100190, P.R. China
- University of Chinese Academy of Sciences , Beijing 100049, P.R. China
| | - Tingxuan Yan
- School of Chemistry and Chemical Engineering, Anhui University of Technology , Ma'anshan, Anhui 243002, P.R. China
| | - Xia Xu
- School of Chemistry and Chemical Engineering, Anhui University of Technology , Ma'anshan, Anhui 243002, P.R. China
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17
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Zolghadr AR, Heydari Dokoohaki M. How Does the P7C3-Series of Neuroprotective Small Molecules Prevent Membrane Disruption? J Chem Inf Model 2017; 57:2009-2019. [PMID: 28691805 DOI: 10.1021/acs.jcim.7b00151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Molecular dynamics (MD) simulations are conducted to suggest a mechanism of action for the aminopropyl dibromocarbazole derivative (P7C3) small molecule, which protects neurons from apoptotic cell death. At first, the influence of embedded Aβ42 stacks on the structure of membrane is studied. Then, the effect of P7C3 molecules on the Aβ42 fibril enriched membrane and Aβ42 fibril depleted membrane (when Aβ42 fibrils are originally dissolved in the aqueous phase) are evaluated. Also, the formation of an amyloid ion channel in the Aβ42 enriched membrane is examined by calculating deuterium order parameter, density profile, and surface thickness. For Aβ42 in the fully inserted state, ion channel-like structures are formed. The presence of P7C3 molecules in this case just postpones membrane destruction but could not prevent pore formation. In contrast, when both Aβ42 and P7C3 molecules are embedded in the aqueous solution, the P7C3 molecules are self-assembled at membrane/ionic aqueous solution interface and prevent the precipitation and deposition of Aβ42 fibrils into the membrane.
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Abstract
Previously published experimental studies have suggested that when the 40-residue amyloid beta peptide is encapsulated in a reverse micelle, it folds into a structure that may nucleate amyloid fibril formation (Yeung, P. S.-W.; Axelsen, P. H. J. Am. Chem. Soc. 2012, 134, 6061 ). The factors that induce the formation of this structure have now been identified in a multi-microsecond simulation of the same reverse micelle system that was studied experimentally. Key features of the polypeptide-micelle interaction include the anchoring of a hydrophobic residue cluster into gaps in the reverse micelle surface, the formation of a beta turn at the anchor point that brings N- and C-terminal segments of the polypeptide into proximity, high ionic strength that promotes intramolecular hydrogen bond formation, and deformation of the reverse micelle surface to facilitate interactions with the surface along the entire length of the polypeptide. Together, these features cause the simulation-derived vibrational spectrum to red shift in a manner that reproduces the red-shift previously reported experimentally. On the basis of these findings, a new mechanism is proposed whereby membranes nucleate fibril formation and facilitate the in-register alignment of polypeptide strands that is characteristic of amyloid fibrils.
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Affiliation(s)
- Gözde Eskici
- Department of Biochemistry & Biophysics, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania 19104, United States
| | - Paul H Axelsen
- Departments of Pharmacology, Biochemistry and Biophysics, and Medicine, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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19
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Kargar F, Emadi S, Fazli H. The molecular behavior of a single β-amyloid inside a dipalmitoylphosphatidylcholine bilayer at three different temperatures: An atomistic simulation study: Aβ interaction with DPPC: Atomistic simulation. Proteins 2017; 85:1298-1310. [PMID: 28342211 DOI: 10.1002/prot.25290] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 03/16/2017] [Accepted: 03/21/2017] [Indexed: 01/29/2023]
Abstract
The behavior of a single Aβ40 molecule within a dipalmitoylphosphatidylcholine (DPPC) bilayer was studied by all-atom molecular dynamics simulations. The effect of membrane structure was investigated on Aβ40 behavior, secondary structure, and insertion depth. Simulations were performed at three temperatures (323, 310, and 300 K) to probe three different bilayer fluidities. Results show that at all above temperatures, the peptide contains two short helices, coil, bend, and turn structures. At 300 K, the peptide contains a region with β structure in C-terminal region. Our results also show that Aβ decreases the bilayer thickness and the order of lipids in its vicinity which leads to water insertion into the bilayer and concomitant increase in the local fluidity. The peptide remains embedded in the bilayer at all temperatures, and become inserted into the bilayer up to several residues at 323 and 310 K. At 310 and 300 K, the dominant interaction energy between Aβ and bilayer changes from electrostatic to van der Waals. It can be proposed that at higher temperatures (e.g., 323 K), Lys28 and the C-terminal region of the peptide play the role of two anchors that keep Aβ inside the top leaflet. This study demonstrates that Aβ molecule can perturb the integrity of cellular membranes. Proteins 2017; 85:1298-1310. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Faezeh Kargar
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45137-66731, Iran
| | - Saeed Emadi
- Department of Biological Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45137-66731, Iran
| | - Hossein Fazli
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45137-66731, Iran.,Department of Biological Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45137-66731, Iran
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20
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Zhang M, Hu R, Ren B, Chen H, Jiang B, Ma J, Zheng J. Molecular Understanding of Aβ-hIAPP Cross-Seeding Assemblies on Lipid Membranes. ACS Chem Neurosci 2017; 8:524-537. [PMID: 27936589 DOI: 10.1021/acschemneuro.6b00247] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Amyloid-β (Aβ) and human islet polypeptide (hIAPP) are the causative agents responsible for Alzheimer's disease (AD) and type II diabetes (T2D), respectively. While numerous studies have reported the cross-seeding behavior of Aβ and hIAPP in solution, little effort has been made to examine the cross-seeding of Aβ and hIAPP in the presence of cell membranes, which is more biologically relevant to the pathological link between AD and T2D. In this work, we computationally study the cross-seeding and adsorption behaviors of Aβ and hIAPP on zwitterionic POPC and anionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylglycerol (POPG) mixed bilayers using all-atom molecular dynamics (MD) simulations, particularly aiming to the effects of the initial orientation of the Aβ-hIAPP assembly and the lipid composition of cell membranes on mutual structural and interaction changes in both Aβ-hIAPP assembly and lipid bilayers at the atomic level. Aβ-hIAPP cross-seeding assembly always preferred to adopt a specific orientation and interface to associate with both lipid bilayers strongly via the N-terminal strands of Aβ. Such membrane-bound orientation explains experimental observation that hybrid Aβ-hIAPP fibrils on cell membranes showed similar morphologies to pure hIAPP fibrils. Moreover, Aβ-hIAPP assembly, regardless of its initial orientations, interacted more strongly with POPC/POPG bilayer than POPC bilayer, indicating that electrostatic interactions are the major forces governing peptide-lipid interactions. Strong electrostatic interactions were also attributed to the formation of Ca2+ bridges connecting both negatively charged Glu of Aβ and PO4 head groups of lipids, which facilitate the association of Aβ-hIAPP with the POPC/POPG bilayer. It was also found that the strong peptide-lipid binding reduced lipid fluidity. Both facts imply that Aβ-hIAPP assembly may induce cell damage by altering calcium homeostasis and cell membrane phase. This work provides a better fundamental understanding of cross-seeding of Aβ and hIAPP on cell membranes and a potential pathological link between AD and T2D.
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Affiliation(s)
- Mingzhen Zhang
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Rundong Hu
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Baiping Ren
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Hong Chen
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Binbo Jiang
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
- College
of Chemical and Biological Engineering Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Jie Ma
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
- State
Key Laboratory of Pollution Control and Resource Reuse School of Environmental
Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jie Zheng
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
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21
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Brown AM, Bevan DR. Influence of sequence and lipid type on membrane perturbation by human and rat amyloid β-peptide (1–42). Arch Biochem Biophys 2017; 614:1-13. [DOI: 10.1016/j.abb.2016.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 11/17/2016] [Accepted: 11/20/2016] [Indexed: 12/20/2022]
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22
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Mona CE, Besserer-Offroy É, Cabana J, Lefrançois M, Boulais PE, Lefebvre MR, Leduc R, Lavigne P, Heveker N, Marsault É, Escher E. Structure–Activity Relationship and Signaling of New Chimeric CXCR4 Agonists. J Med Chem 2016; 59:7512-24. [DOI: 10.1021/acs.jmedchem.6b00566] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Christine E. Mona
- Department
of Pharmacology-Physiology, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Élie Besserer-Offroy
- Department
of Pharmacology-Physiology, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Jérôme Cabana
- Department
of Pharmacology-Physiology, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Marilou Lefrançois
- Department
of Pharmacology-Physiology, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Philip E. Boulais
- Department
of Pharmacology-Physiology, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Marie-Reine Lefebvre
- Department
of Pharmacology-Physiology, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Richard Leduc
- Department
of Pharmacology-Physiology, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Pierre Lavigne
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Nikolaus Heveker
- Department of Biochemistry and Molecular
Medicine, Centre de recherche du CHU Sainte-Justine, Université de Montréal, Montréal, QC H3T 1C4, Canada
| | - Éric Marsault
- Department
of Pharmacology-Physiology, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Emanuel Escher
- Department
of Pharmacology-Physiology, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Institut
de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
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23
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Sridhar A, Kumar A, Dasmahapatra AK. Multi-scale molecular dynamics study of cholera pentamer binding to a GM1-phospholipid membrane. J Mol Graph Model 2016; 68:236-251. [PMID: 27474868 DOI: 10.1016/j.jmgm.2016.07.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/15/2016] [Accepted: 07/21/2016] [Indexed: 10/21/2022]
Abstract
The AB5 type toxin produced by the Vibrio cholerae bacterium is the causative agent of the cholera disease. The cholera toxin (CT) has been shown to bind specifically to GM1 glycolipids on the membrane surface. This binding of CT to the membrane is the initial step in its endocytosis and has been postulated to cause significant disruption to the membrane structure. In this work, we have carried out a combination of coarse-grain and atomistic simulations to study the binding of CT to a membrane modelled as an asymmetrical GM1-DPPC bilayer. Simulation results indicate that the toxin binds to the membrane through only three of its five B subunits, in effect resulting in a tilted bound configuration. Additionally, the binding of the CT can increase the area per lipid of GM1 leaflet, which in turn can cause the membrane regions interacting with the bound subunits to experience significant bilayer thinning and lipid tail disorder across both the leaflets.
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Affiliation(s)
- Akshay Sridhar
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India
| | - Amit Kumar
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India.
| | - Ashok Kumar Dasmahapatra
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India.
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24
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Lockhart C, Klimov DK. The Alzheimer's disease A β peptide binds to the anionic DMPS lipid bilayer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1118-28. [DOI: 10.1016/j.bbamem.2016.03.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 02/26/2016] [Accepted: 03/01/2016] [Indexed: 11/24/2022]
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25
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Teixeira VH, Vila-Viçosa D, Reis PBPS, Machuqueiro M. pKa Values of Titrable Amino Acids at the Water/Membrane Interface. J Chem Theory Comput 2016; 12:930-4. [DOI: 10.1021/acs.jctc.5b01114] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Vitor H. Teixeira
- Centro de Química
e Bioquímica, Departamento de Química e Bioquímica,
Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Diogo Vila-Viçosa
- Centro de Química
e Bioquímica, Departamento de Química e Bioquímica,
Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Pedro B. P. S. Reis
- Centro de Química
e Bioquímica, Departamento de Química e Bioquímica,
Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Miguel Machuqueiro
- Centro de Química
e Bioquímica, Departamento de Química e Bioquímica,
Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
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26
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Cabana J, Holleran B, Leduc R, Escher E, Guillemette G, Lavigne P. Identification of Distinct Conformations of the Angiotensin-II Type 1 Receptor Associated with the Gq/11 Protein Pathway and the β-Arrestin Pathway Using Molecular Dynamics Simulations. J Biol Chem 2015; 290:15835-15854. [PMID: 25934394 DOI: 10.1074/jbc.m114.627356] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Indexed: 01/14/2023] Open
Abstract
Biased signaling represents the ability of G protein-coupled receptors to engage distinct pathways with various efficacies depending on the ligand used or on mutations in the receptor. The angiotensin-II type 1 (AT1) receptor, a prototypical class A G protein-coupled receptor, can activate various effectors upon stimulation with the endogenous ligand angiotensin-II (AngII), including the Gq/11 protein and β-arrestins. It is believed that the activation of those two pathways can be associated with distinct conformations of the AT1 receptor. To verify this hypothesis, microseconds of molecular dynamics simulations were computed to explore the conformational landscape sampled by the WT-AT1 receptor, the N111G-AT1 receptor (constitutively active and biased for the Gq/11 pathway), and the D74N-AT1 receptor (biased for the β-arrestin1 and -2 pathways) in their apo-forms and in complex with AngII. The molecular dynamics simulations of the AngII-WT-AT1, N111G-AT1, and AngII-N111G-AT1 receptors revealed specific structural rearrangements compared with the initial and ground state of the receptor. Simulations of the D74N-AT1 receptor revealed that the mutation stabilizes the receptor in the initial ground state. The presence of AngII further stabilized the ground state of the D74N-AT1 receptor. The biased agonist [Sar(1),Ile(8)]AngII also showed a preference for the ground state of the WT-AT1 receptor compared with AngII. These results suggest that activation of the Gq/11 pathway is associated with a specific conformational transition stabilized by the agonist, whereas the activation of the β-arrestin pathway is linked to the stabilization of the ground state of the receptor.
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Affiliation(s)
- Jérôme Cabana
- Departments of Pharmacology, Faculty of Medicine and Health Sciences, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4; PROTEO (Quebec Network on Protein Structure, Function, and Engineering), Université Laval, Québec, Québec G1V 0A6, Canada
| | - Brian Holleran
- Departments of Pharmacology, Faculty of Medicine and Health Sciences, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4
| | - Richard Leduc
- Departments of Pharmacology, Faculty of Medicine and Health Sciences, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4
| | - Emanuel Escher
- Departments of Pharmacology, Faculty of Medicine and Health Sciences, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4
| | - Gaétan Guillemette
- Departments of Pharmacology, Faculty of Medicine and Health Sciences, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4
| | - Pierre Lavigne
- PROTEO (Quebec Network on Protein Structure, Function, and Engineering), Université Laval, Québec, Québec G1V 0A6, Canada; Biochemistry, Faculty of Medicine and Health Sciences, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4.
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27
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Montpas N, Cabana J, St-Onge G, Gravel S, Morin G, Kuroyanagi T, Lavigne P, Fujii N, Oishi S, Heveker N. Mode of binding of the cyclic agonist peptide TC14012 to CXCR7: identification of receptor and compound determinants. Biochemistry 2015; 54:1505-15. [PMID: 25669416 DOI: 10.1021/bi501526s] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The chemokine receptor CXCR7 is an atypical CXCL12 receptor that, as opposed to the classical CXCL12 receptor CXCR4, signals preferentially via the β-arrestin pathway and does not mediate chemotaxis. We previously reported that the cyclic peptide TC14012, a potent CXCR4 antagonist, also engaged CXCR7, albeit with lower potency. Surprisingly, the compound activated the CXCR7-arrestin pathway. The reason underlying the opposite effects of TC14012 on CXCR4 and CXCR7, and the mode of binding of TC14012 to CXCR7, remained unclear. The mode of binding of TC14012 to CXCR4 is known from cocrystallization of its analogue CVX15 with CXCR4. We here report the the mode of binding of TC14012 to CXCR7 by combining the use of compound analogues, receptor mutants, and molecular modeling. We find that the mode of binding of TC14012 to CXCR7 is indeed similar to that of CVX15 to CXCR4, with compound positions Arg2 and Arg14 engaging CXCR7 key residues D179(4.60) (on the tip of transmembrane domain 4) and D275(6.58) (on the tip of transmembrane domain 6), respectively. Interestingly, the TC14012 parent compound T140 is not a CXCR7 agonist, because of conformational constraints in its pharmacophore, which in TC14012 are relieved through C-terminal amidation. However, an engineered salt bridge between the CXCR7 ECL2 substitution R197D and compound residue Arg1 permitted T140 agonism by repositioning the compound in the binding pocket. In conclusion, our results show that the opposite effect of TC14012 on CXCR4 and CXCR7 is not explained by different binding modes. Rather, engagement of the interface between transmembrane domains and extracellular loops readily triggers CXCR7, but not CXCR4, activation.
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Affiliation(s)
- Nicolas Montpas
- Research Centre, Sainte-Justine Hospital, University of Montreal , Montréal H3T 1C5, Canada
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Basu I, Mukhopadhyay C. Insights into binding of cholera toxin to GM1 containing membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:15244-15252. [PMID: 25425333 DOI: 10.1021/la5036618] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Interactions of cholera toxin (CT) with membrane are associated with the massive secretory diarrhea seen in Asiatic cholera. Ganglioside GM1 has been shown to be responsible for the binding of the B subunit of cholera toxin (CT-B), which then helps CT to pass through the membrane, but the exact mechanism remains to be explored. In this work, we have carried out atomistic scale molecular dynamics simulation to investigate the structural changes of CT upon membrane binding and alteration in membrane structure and dynamics. Starting from the initial structure where the five units of B subunit bind with five GM1, only three of five units remain bound and the whole CT is tilted such that the three binding units are deeper in the membrane. The lipids that are in contact with those units of the CT-B behave differently from the rest of the lipids. Altogether, our results demonstrate the atomistic interaction of CT with GM1 containing lipid membrane and provide a probable mechanism of the early stage alteration of lipid structure and dynamics, which can make a passage for penetration of CT on membrane surface.
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Affiliation(s)
- Ipsita Basu
- Department of Chemistry, University of Calcutta , 92, A. P. C. Road, Kolkata - 700009, India
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29
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Qiu L, Buie C, Cheng KH, Vaughn MW. Scaling and alpha-helix regulation of protein relaxation in a lipid bilayer. J Chem Phys 2014; 141:225101. [PMID: 25494768 PMCID: PMC4265037 DOI: 10.1063/1.4902229] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 11/10/2014] [Indexed: 11/15/2022] Open
Abstract
Protein conformation and orientation in the lipid membrane plays a key role in many cellular processes. Here we use molecular dynamics simulation to investigate the relaxation and C-terminus diffusion of a model helical peptide: beta-amyloid (Aβ) in a lipid membrane. We observed that after the helical peptide was initially half-embedded in the extracelluar leaflet of phosphatidylcholine (PC) or PC/cholesterol (PC/CHOL) membrane, the C-terminus diffused across the membrane and anchored to PC headgroups of the cytofacial lipid leaflet. In some cases, the membrane insertion domain of the Aβ was observed to partially unfold. Applying a sigmoidal fit to the process, we found that the characteristic velocity of the C-terminus, as it moved to its anchor site, scaled with θu (-4/3), where θu is the fraction of the original helix that was lost during a helix to coil transition. Comparing this scaling with that of bead-spring models of polymer relaxation suggests that the C-terminus velocity is highly regulated by the peptide helical content, but that it is independent of the amino acid type. The Aβ was stabilized by the attachment of the positive Lys28 side chain to the negative phosphate of PC or 3β oxygen of CHOL in the extracellular lipid leaflet and of the C-terminus to its anchor site in the cytofacial lipid leaflet.
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Affiliation(s)
- Liming Qiu
- Department of Physics, Texas Tech University, Lubbock, Texas 79409, USA
| | - Creighton Buie
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, USA
| | - Kwan Hon Cheng
- Department of Physics, Texas Tech University, Lubbock, Texas 79409, USA
| | - Mark W Vaughn
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, USA
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30
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Zhang M, Zhao J, Zheng J. Molecular understanding of a potential functional link between antimicrobial and amyloid peptides. SOFT MATTER 2014; 10:7425-7451. [PMID: 25105988 DOI: 10.1039/c4sm00907j] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Antimicrobial and amyloid peptides do not share common sequences, typical secondary structures, or normal biological activity but both the classes of peptides exhibit membrane-disruption ability to induce cell toxicity. Different membrane-disruption mechanisms have been proposed for antimicrobial and amyloid peptides, individually, some of which are not exclusive to either peptide type, implying that certain common principles may govern the folding and functions of different cytolytic peptides and associated membrane disruption mechanisms. Particularly, some antimicrobial and amyloid peptides have been identified to have dual complementary amyloid and antimicrobial properties, suggesting a potential functional link between amyloid and antimicrobial peptides. Given that some similar structural and membrane-disruption characteristics exist between the two classes of peptides, this review summarizes major findings, recent advances, and future challenges related to antimicrobial and amyloid peptides and strives to illustrate the similarities, differences, and relationships in the sequences, structures, and membrane interaction modes between amyloid and antimicrobial peptides, with a special focus on direct interactions of the peptides with the membranes. We hope that this review will stimulate further research at the interface of antimicrobial and amyloid peptides - which has been studied less intensively than either type of peptides - to decipher a possible link between both amyloid pathology and antimicrobial activity, which can guide drug design and peptide engineering to influence peptide-membrane interactions important in human health and diseases.
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Affiliation(s)
- Mingzhen Zhang
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, USA.
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31
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Lockhart C, Klimov DK. Binding of Aβ peptide creates lipid density depression in DMPC bilayer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2678-88. [DOI: 10.1016/j.bbamem.2014.07.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/04/2014] [Accepted: 07/07/2014] [Indexed: 12/12/2022]
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Poojari C, Strodel B. Stability of transmembrane amyloid β-peptide and membrane integrity tested by molecular modeling of site-specific Aβ42 mutations. PLoS One 2013; 8:e78399. [PMID: 24244308 PMCID: PMC3820573 DOI: 10.1371/journal.pone.0078399] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 09/11/2013] [Indexed: 11/20/2022] Open
Abstract
Interactions of the amyloid β-protein (Aβ) with neuronal cell membranes, leading to the disruption of membrane integrity, are considered to play a key role in the development of Alzheimer’s disease. Natural mutations in Aβ42, such as the Arctic mutation (E22G) have been shown to increase Aβ42 aggregation and neurotoxicity, leading to the early-onset of Alzheimer’s disease. A correlation between the propensity of Aβ42 to form protofibrils and its effect on neuronal dysfunction and degeneration has been established. Using rational mutagenesis of the Aβ42 peptide it was further revealed that the aggregation of different Aβ42 mutants in lipid membranes results in a variety of polymorphic aggregates in a mutation dependent manner. The mutant peptides also have a variable ability to disrupt bilayer integrity. To further test the connection between Aβ42 mutation and peptide–membrane interactions, we perform molecular dynamics simulations of membrane-inserted Aβ42 variants (wild-type and E22G, D23G, E22G/D23G, K16M/K28M and K16M/E22G/D23G/K28M mutants) as β-sheet monomers and tetramers. The effects of charged residues on transmembrane Aβ42 stability and membrane integrity are analyzed at atomistic level. We observe an increased stability for the E22G Aβ42 peptide and a decreased stability for D23G compared to wild-type Aβ42, while D23G has the largest membrane-disruptive effect. These results support the experimental observation that the altered toxicity arising from mutations in Aβ is not only a result of the altered aggregation propensity, but also originates from modified Aβ interactions with neuronal membranes.
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Affiliation(s)
- Chetan Poojari
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich GmbH, Jülich, Germany
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- * E-mail:
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33
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Gapsys V, de Groot BL, Briones R. Computational analysis of local membrane properties. J Comput Aided Mol Des 2013; 27:845-58. [PMID: 24150904 PMCID: PMC3882000 DOI: 10.1007/s10822-013-9684-0] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 10/07/2013] [Indexed: 11/29/2022]
Abstract
In the field of biomolecular simulations, dynamics of phospholipid membranes is of special interest. A number of proteins, including channels, transporters, receptors and short peptides are embedded in lipid bilayers and tightly interact with phospholipids. While the experimental measurements report on the spatial and/or temporal average membrane properties, simulation results are not restricted to the average properties. In the current study, we present a collection of methods for an efficient local membrane property calculation, comprising bilayer thickness, area per lipid, deuterium order parameters, Gaussian and mean curvature. The local membrane property calculation allows for a direct mapping of the membrane features, which subsequently can be used for further analysis and visualization of the processes of interest. The main features of the described methods are highlighted in a number of membrane systems, namely: a pure dimyristoyl-phosphatidyl-choline (DMPC) bilayer, a fusion peptide interacting with a membrane, voltage-dependent anion channel protein embedded in a DMPC bilayer, cholesterol enriched bilayer and a coarse grained simulation of a curved palmitoyl-oleoyl-phosphatidyl-choline lipid membrane. The local membrane property analysis proves to provide an intuitive and detailed view on the observables that are otherwise interpreted as averaged bilayer properties.
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Affiliation(s)
- Vytautas Gapsys
- Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany,
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34
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Binding, conformational transition and dimerization of amyloid-β peptide on GM1-containing ternary membrane: insights from molecular dynamics simulation. PLoS One 2013; 8:e71308. [PMID: 23951128 PMCID: PMC3739818 DOI: 10.1371/journal.pone.0071308] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 06/27/2013] [Indexed: 12/16/2022] Open
Abstract
Interactions of amyloid-β (Aβ) with neuronal membrane are associated with the progression of Alzheimer's disease (AD). Ganglioside GM1 has been shown to promote the structural conversion of Aβ and increase the rate of peptide aggregation; but the exact nature of interaction driving theses processes remains to be explored. In this work, we have carried out atomistic-scale computer simulations (totaling 2.65 µs) to investigate the behavior of Aβ monomer and dimers in GM1-containing raft-like membrane. The oligosaccharide head-group of GM1 was observed to act as scaffold for Aβ-binding through sugar-specific interactions. Starting from the initial helical peptide conformation, a β-hairpin motif was formed at the C-terminus of the GM1-bound Aβ-monomer; that didn't appear in absence of GM1 (both in fluid POPC and liquid-ordered cholesterol/POPC bilayers and also in aqueous medium) within the simulation time span. For Aβ-dimers, the β-structure was further enhanced by peptide-peptide interactions, which might influence the propensity of Aβ to aggregate into higher-ordered structures. The salt-bridges and inter-peptide hydrogen bonds were found to account for dimer stability. We observed spontaneous formation of intra-peptide D(23)-K(28) salt-bridge and a turn at V(24)GSN(27) region - long been accepted as characteristic structural-motifs for amyloid self-assembly. Altogether, our results provide atomistic details of Aβ-GM1 and Aβ-Aβ interactions and demonstrate their importance in the early-stages of GM1-mediated Aβ-oligomerisation on membrane surface.
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35
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Lemkul JA, Bevan DR. Aggregation of Alzheimer’s Amyloid β-Peptide in Biological Membranes: A Molecular Dynamics Study. Biochemistry 2013; 52:4971-80. [DOI: 10.1021/bi400562x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Justin A. Lemkul
- Department of Biochemistry, Virginia Polytechnic Institute
and State University, Blacksburg, Virginia 24061, United States
| | - David R. Bevan
- Department of Biochemistry, Virginia Polytechnic Institute
and State University, Blacksburg, Virginia 24061, United States
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36
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Yu X, Wang Q, Pan Q, Zhou F, Zheng J. Molecular interactions of Alzheimer amyloid-β oligomers with neutral and negatively charged lipid bilayers. Phys Chem Chem Phys 2013; 15:8878-89. [PMID: 23493873 DOI: 10.1039/c3cp44448a] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Interaction of p3 (Aβ(17-42)) peptides with cell membranes is crucial for the understanding of amyloid toxicity associated with Alzheimer's disease (AD). Such p3-membrane interactions are considered to induce the disruption of membrane permeability and integrity, but the exact mechanisms of how p3 aggregates, particularly small p3 oligomers, induce receptor-independent membrane disruption are not yet completely understood. Here, we investigate the adsorption, orientation, and surface interaction of the p3 pentamer with lipid bilayers composed of both pure zwitterionic POPC (palmitoyl-oleoyl-phosphatidylcholine) and mixed anionic POPC-POPG (palmitoyl-oleoyl-phosphatidylglycerol) (3 : 1) lipids using explicit-solvent molecular dynamics (MD) simulations. MD simulation results show that the p3 pentamer has much stronger interactions with mixed POPC-POPG lipids than pure POPC lipids, consistent with experimental observation that Aβ adsorption and fibrillation are enhanced on anionic lipid bilayers. Although electrostatic interactions are main attractive forces to drive the p3 pentamer to adsorb on the bilayer surface, the adsorption of the p3 pentamer on the lipid bilayer with C-terminal β-strands facing toward the bilayer surface is a net outcome of different competitions between p3 peptides-lipid bilayer and ions-p3-bilayer interactions. More importantly, Ca(2+) ions are found to form ionic bridges to associate negatively charged residues of p3 with anionic headgroups of the lipid bilayer, resulting in Aβ-Ca(2+)-PO4(-) complexes. Intensive Ca(2+) bound to the lipid bilayer and Ca(2+) ionic bridges may lead to Ca(2+) hemostasis responsible for neuronal dysfunction and death. This work provides insights into the mutual structure, dynamics, and interactions of both Aβ peptides and lipid bilayers at the atomic level, which expand our understanding of the complex behavior of amyloid-induced membrane disruption.
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Affiliation(s)
- Xiang Yu
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA
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37
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Poojari C, Kukol A, Strodel B. How the amyloid-β peptide and membranes affect each other: An extensive simulation study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:327-39. [DOI: 10.1016/j.bbamem.2012.09.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 09/03/2012] [Accepted: 09/04/2012] [Indexed: 11/24/2022]
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38
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Ahyayauch H, Raab M, Busto JV, Andraka N, Arrondo JLR, Masserini M, Tvaroska I, Goñi FM. Binding of β-amyloid (1-42) peptide to negatively charged phospholipid membranes in the liquid-ordered state: modeling and experimental studies. Biophys J 2013; 103:453-463. [PMID: 22947861 DOI: 10.1016/j.bpj.2012.06.043] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Revised: 06/22/2012] [Accepted: 06/27/2012] [Indexed: 12/12/2022] Open
Abstract
To explore the initial stages of amyloid β peptide (Aβ42) deposition on membranes, we have studied the interaction of Aβ42 in the monomeric form with lipid monolayers and with bilayers in either the liquid-disordered or the liquid-ordered (L(o)) state, containing negatively charged phospholipids. Molecular dynamics (MD) simulations of the system have been performed, as well as experimental measurements. For bilayers in the L(o) state, in the absence of the negatively charged lipids, interaction is weak and it cannot be detected by isothermal calorimetry. However, in the presence of phosphatidic acid, or of cardiolipin, interaction is detected by different methods and in all cases interaction is strongest with lower (2.5-5 mol%) than higher (10-20 mol%) proportions of negatively charged phospholipids. Liquid-disordered bilayers consistently allowed a higher Aβ42 binding than L(o) ones. Thioflavin T assays and infrared spectroscopy confirmed a higher proportion of β-sheet formation under conditions when higher peptide binding was measured. The experimental results were supported by MD simulations. We used 100 ns MD to examine interactions between Aβ42 and three different 512 lipid bilayers consisting of palmitoylsphingomyelin, dimyristoyl phosphatidic acid, and cholesterol in three different proportions. MD pictures are different for the low- and high-charge bilayers, in the former case the peptide is bound through many contact points to the bilayer, whereas for the bilayer containing 20 mol% anionic phospholipid only a small fragment of the peptide appears to be bound. The MD results indicate that the binding and fibril formation on the membrane surface depends on the composition of the bilayer, and is the result of a subtle balance of many inter- and intramolecular interactions between the Aβ42 and membrane.
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Affiliation(s)
- Hasna Ahyayauch
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Michal Raab
- Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jon V Busto
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Nagore Andraka
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - José-Luis R Arrondo
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Massimo Masserini
- Department of Experimental Medicine, University of Milano Bicocca, Monza, Italy
| | - Igor Tvaroska
- Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Félix M Goñi
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain.
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39
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Cabana J, Holleran B, Beaulieu MÈ, Leduc R, Escher E, Guillemette G, Lavigne P. Critical hydrogen bond formation for activation of the angiotensin II type 1 receptor. J Biol Chem 2012; 288:2593-604. [PMID: 23223579 DOI: 10.1074/jbc.m112.395939] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled receptors contain selectively important residues that play central roles in the conformational changes that occur during receptor activation. Asparagine 111 (N111(3.35)) is such a residue within the angiotensin II type 1 (AT(1)) receptor. Substitution of N111(3.35) for glycine leads to a constitutively active receptor, whereas substitution for tryptophan leads to an inactivable receptor. Here, we analyzed the AT(1) receptor and two mutants (N111G and N111W) by molecular dynamics simulations, which revealed a novel molecular switch involving the strictly conserved residue D74(2.50). Indeed, D74(2.50) forms a stable hydrogen bond (H-bond) with the residue in position 111(3.35) in the wild-type and the inactivable receptor. However, in the constitutively active mutant N111G-AT(1) receptor, residue D74 is reoriented to form a new H-bond with another strictly conserved residue, N46(1.50). When expressed in HEK293 cells, the mutant N46G-AT(1) receptor was poorly activable, although it retained a high binding affinity. Interestingly, the mutant N46G/N111G-AT(1) receptor was also inactivable. Molecular dynamics simulations also revealed the presence of a cluster of hydrophobic residues from transmembrane domains 2, 3, and 7 that appears to stabilize the inactive form of the receptor. Whereas this hydrophobic cluster and the H-bond between D74(2.50) and W111(3.35) are more stable in the inactivable N111W-AT(1) receptor, the mutant N111W/F77A-AT(1) receptor, designed to weaken the hydrophobic core, showed significant agonist-induced signaling. These results support the potential for the formation of an H-bond between residues D74(2.50) and N46(1.50) in the activation of the AT(1) receptor.
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Affiliation(s)
- Jérôme Cabana
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quecec J1H 5N4, Canada
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40
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Lemkul JA, Bevan DR. The role of molecular simulations in the development of inhibitors of amyloid β-peptide aggregation for the treatment of Alzheimer's disease. ACS Chem Neurosci 2012; 3:845-56. [PMID: 23173066 DOI: 10.1021/cn300091a] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 08/27/2012] [Indexed: 12/26/2022] Open
Abstract
The pathogenic aggregation of the amyloid β-peptide (Aβ) is considered a hallmark of the progression of Alzheimer's disease, the leading cause of senile dementia in the elderly and one of the principal causes of death in the United States. In the absence of effective therapeutics, the incidence and economic burden associated with the disease are expected to rise dramatically in the coming decades. Targeting Aβ aggregation is an attractive therapeutic approach, though structural insights into the nature of Aβ aggregates from traditional experiments are elusive, making drug design difficult. Theoretical methods have been used for several years to augment experimental work and drive progress forward in Alzheimer's drug design. In this Review, we will describe how two common techniques, molecular docking and molecular dynamics simulations, are being applied in developing small molecules as effective therapeutics against monomeric, oligomeric, and fibrillated forms of Aβ. Recent successes and important limitations will be discussed, and we conclude by providing a perspective on the future of this field by citing recent examples of sophisticated approaches used to better characterize interactions of small molecules with Aβ and other amyloidogenic proteins.
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Affiliation(s)
- Justin A. Lemkul
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - David R. Bevan
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
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41
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Piggot TJ, Piñeiro Á, Khalid S. Molecular Dynamics Simulations of Phosphatidylcholine Membranes: A Comparative Force Field Study. J Chem Theory Comput 2012; 8:4593-609. [DOI: 10.1021/ct3003157] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Thomas J. Piggot
- School of Chemistry, University
of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom
| | - Ángel Piñeiro
- Department of Applied Physics,
University of Santiago de Compostela, Campus Vida, 15782, Santiago
de Compostela, Spain
| | - Syma Khalid
- School of Chemistry, University
of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom
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42
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Yu X, Zheng J. Cholesterol Promotes the Interaction of Alzheimer β-Amyloid Monomer with Lipid Bilayer. J Mol Biol 2012; 421:561-71. [DOI: 10.1016/j.jmb.2011.11.006] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 11/01/2011] [Accepted: 11/02/2011] [Indexed: 11/29/2022]
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43
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Morriss-Andrews A, Shea JE. Kinetic pathways to peptide aggregation on surfaces: the effects of β-sheet propensity and surface attraction. J Chem Phys 2012; 136:065103. [PMID: 22360223 DOI: 10.1063/1.3682986] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mechanisms of peptide aggregation on hydrophobic surfaces are explored using molecular dynamics simulations with a coarse-grained peptide representation. Systems of peptides are studied with varying degrees of backbone rigidity (a measure of β-sheet propensity) and degrees of attraction between their hydrophobic residues and the surface. Multiple pathways for aggregation are observed, depending on the surface attraction and peptide β-sheet propensity. For the case of a single-layered β-sheet fibril forming on the surface (a dominant structure seen in all simulations), three mechanisms are observed: (a) a condensation-ordering transition where a bulk-formed amorphous aggregate binds to the surface and subsequently rearranges to form a fibril; (b) the initial formation of a single-layered fibril in the bulk depositing flat on the surface; and (c) peptides binding individually to the surface and nucleating fibril formation by individual peptide deposition. Peptides with a stiffer chiral backbone prefer mechanism (b) over (a), and stronger surface attractions prefer mechanism (c) over (a) and (b). Our model is compared to various similar experimental systems, and an agreement was found in terms of the surface increasing the degree of fibrillar aggregation, with the directions of fibrillar growth matching the crystallographic symmetry of the surface. Our simulations provide details of aggregate growth mechanisms on scales inaccessible to either experiment or atomistic simulations.
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Affiliation(s)
- Alex Morriss-Andrews
- Department of Physics, University of California Santa Barbara, Santa Barbara, California 93106, USA
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44
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Masters CL, Selkoe DJ. Biochemistry of amyloid β-protein and amyloid deposits in Alzheimer disease. Cold Spring Harb Perspect Med 2012; 2:a006262. [PMID: 22675658 PMCID: PMC3367542 DOI: 10.1101/cshperspect.a006262] [Citation(s) in RCA: 395] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Progressive cerebral deposition of the amyloid β-protein (Aβ) in brain regions serving memory and cognition is an invariant and defining feature of Alzheimer disease. A highly similar but less robust process accompanies brain aging in many nondemented humans, lower primates, and some other mammals. The discovery of Aβ as the subunit of the amyloid fibrils in meningocerebral blood vessels and parenchymal plaques has led to innumerable studies of its biochemistry and potential cytotoxic properties. Here we will review the discovery of Aβ, numerous aspects of its complex biochemistry, and current attempts to understand how a range of Aβ assemblies, including soluble oligomers and insoluble fibrils, may precipitate and promote neuronal and glial alterations that underlie the development of dementia. Although the role of Aβ as a key molecular factor in the etiology of Alzheimer disease remains controversial, clinical trials of amyloid-lowering agents, reviewed elsewhere in this book, are poised to resolve the question of its pathogenic primacy.
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Affiliation(s)
- Colin L Masters
- The Mental Health Research Institute, The University of Melbourne, Parkville 3010, Australia.
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45
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Pulawski W, Ghoshdastider U, Andrisano V, Filipek S. Ubiquitous amyloids. Appl Biochem Biotechnol 2012; 166:1626-43. [PMID: 22350870 PMCID: PMC3324686 DOI: 10.1007/s12010-012-9549-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Accepted: 01/05/2012] [Indexed: 01/04/2023]
Abstract
The common view of amyloids and prion proteins is that they are associated with many currently incurable diseases and present a great danger to an organism. This danger comes from the fact that not only prion proteins, but also the infectious form(s) of amyloids, as it has been shown recently, are able to transmit the disease. On the other hand, organisms take advantage of the strength and durability of specific forms of amyloids. Such forms do not spread any disease. Also, in nanotechnology there is a constantly growing need to employ amyloid fibrils in many industrial applications. With increasing knowledge about amyloids and prion proteins we are aware that the amyloidal state is inherent to any protein, making the problem of amyloid formation a central one in aging-related diseases. However, the “good” amyloids can be beneficial and even necessary for our health. Furthermore, because of their mechanical properties, the amyloids are of great interest to engineers.
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Affiliation(s)
- Wojciech Pulawski
- Faculty of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warsaw, Poland
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The Structure of Intrinsically Disordered Peptides Implicated in Amyloid Diseases: Insights from Fully Atomistic Simulations. COMPUTATIONAL MODELING OF BIOLOGICAL SYSTEMS 2012. [DOI: 10.1007/978-1-4614-2146-7_9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Qiu L, Buie C, Reay A, Vaughn MW, Cheng KH. Molecular dynamics simulations reveal the protective role of cholesterol in β-amyloid protein-induced membrane disruptions in neuronal membrane mimics. J Phys Chem B 2011; 115:9795-812. [PMID: 21740063 PMCID: PMC3163122 DOI: 10.1021/jp2012842] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Interactions of β-amyloid (Aβ) peptides with neuronal membranes have been associated with the pathogenesis of Alzheimer's disease (AD); however, the molecular details remain unclear. We used atomistic molecular dynamics (MD) simulations to study the interactions of Aβ(40) and Aβ(42) with model neuronal membranes. The differences between cholesterol-enriched and depleted lipid domains were investigated by the use of model phosphatidylcholine (PC) lipid bilayers with and without 40 mol % cholesterol. A total of 16 independent 200 ns simulation replicates were investigated. The surface area per lipid, bilayer thickness, water permeability barrier, and lipid order parameter, which are sensitive indicators of membrane disruption, were significantly altered by the inserted state of the protein. We conclude that cholesterol protects Aβ-induced membrane disruption and inhibits β-sheet formation of Aβ on the lipid bilayer. The latter could represent a two-dimensional (2D) seeding template for the formation of toxic oligomeric Aβ in the pathogenesis of AD.
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Affiliation(s)
- Liming Qiu
- Department of Physics, Texas Tech University, Lubbock, Texas 79409
| | - Creighton Buie
- Department of Physics, Texas Tech University, Lubbock, Texas 79409
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409
| | - Andrew Reay
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409
| | - Mark W. Vaughn
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409
| | - Kwan Hon Cheng
- Department of Physics, Texas Tech University, Lubbock, Texas 79409
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Lemkul JA, Bevan DR. Lipid composition influences the release of Alzheimer's amyloid β-peptide from membranes. Protein Sci 2011; 20:1530-45. [PMID: 21692120 DOI: 10.1002/pro.678] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 05/08/2011] [Accepted: 06/09/2011] [Indexed: 12/15/2022]
Abstract
The behavior of the amyloid β-peptide (Aβ) within a membrane environment is integral to its toxicity and the progression of Alzheimer's disease. Ganglioside GM1 has been shown to enhance the aggregation of Aβ, but the underlying mechanism is unknown. Using atomistic molecular dynamics simulations, we explored the interactions between the 40-residue alloform of Aβ (Aβ(40) ) and several model membranes, including pure palmitoyloleoylphosphatidylcholine (POPC) and palmitoyloleoylphosphatidylserine (POPS), an equimolar mixture of POPC and palmitoyloleoylphosphatidylethanolamine (POPE), and lipid rafts, both with and without GM1, to understand the behavior of Aβ(40) in various membrane microenvironments. Aβ(40) remained inserted in POPC, POPS, POPC/POPE, and raft membranes, but in several instances exited the raft containing GM1. Aβ(40) interacted with GM1 largely through hydrogen bonding, producing configurations containing β-strands with C-termini that, in some cases, exited the membrane and became exposed to solvent. These observations provide insight into the release of Aβ from the membrane, a previously uncharacterized process of the Aβ aggregation pathway.
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Affiliation(s)
- Justin A Lemkul
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, USA
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Manna M, Mukhopadhyay C. Molecular dynamics simulations of the interactions of kinin peptides with an anionic POPG bilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:3713-3722. [PMID: 21355573 DOI: 10.1021/la104046z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have performed molecular dynamics simulations of peptide hormone bradykinin (BK) and its fragment des-Arg9-BK in the presence of an anionic lipid bilayer, with an aim toward delineating the mechanism of action related to their bioactivity. Starting from the initial aqueous environment, both of the peptides are quickly adsorbed and stabilized on the cell surface. Whereas BK exhibits a stronger interaction with the membrane and prefers to stay on the interface, des-Arg9-BK, with the loss of C-terminal Arg, penetrates further. The heterogeneous lipid-water interface induces β-turn-like structure in the otherwise inherently flexible peptides. In the membrane-bound state, we observed C-terminal β-turn formation in BK, whereas for des-Arg9-BK, with the deletion of Arg9, turn formation occurred in the middle of the peptide. The basic Arg residues anchor the peptide to the bilayer by strong electrostatic interactions with charged lipid headgroups. Simulations with different starting orientations of the peptides with respect to the bilayer surface lead to the same observations, namely, the relative positioning of the peptides on the membrane surface, deeper penetration of the des-Arg9-BK, and the formation of turn structures. The lipid headgroups adjacent to the bound peptides become substantially tilted, causing bilayer thinning near the peptide contact region and increase the degree of disorder in nearby lipids. Again, because of hydrogen bonding with the peptide, the neighboring lipid's polar heads exhibit considerably reduced flexibility. Corroborating findings from earlier experiments, our results provide important information about how the lipid environment promotes peptide orientation/conformation and how the peptide adapts to the environment.
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Affiliation(s)
- Moutusi Manna
- Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata-700 009, India
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Miller AE, Petersen PB, Hollars CW, Saykally RJ, Heyda J, Jungwirth P. Behavior of β-Amyloid 1−16 at the Air−Water Interface at Varying pH by Nonlinear Spectroscopy and Molecular Dynamics Simulations. J Phys Chem A 2011; 115:5873-80. [DOI: 10.1021/jp110103j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Abigail E. Miller
- Department of Chemistry, University of California, Berkeley, California 94720-1460, United States
- Chemistry, Materials, and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Poul B. Petersen
- Department of Chemistry, University of California, Berkeley, California 94720-1460, United States
| | - Christopher W. Hollars
- Chemistry, Materials, and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Richard J. Saykally
- Department of Chemistry, University of California, Berkeley, California 94720-1460, United States
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