1
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Belghit H, Spivak M, Dauchez M, Baaden M, Jonquet-Prevoteau J. From complex data to clear insights: visualizing molecular dynamics trajectories. FRONTIERS IN BIOINFORMATICS 2024; 4:1356659. [PMID: 38665177 PMCID: PMC11043564 DOI: 10.3389/fbinf.2024.1356659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 03/14/2024] [Indexed: 04/28/2024] Open
Abstract
Advances in simulations, combined with technological developments in high-performance computing, have made it possible to produce a physically accurate dynamic representation of complex biological systems involving millions to billions of atoms over increasingly long simulation times. The analysis of these computed simulations is crucial, involving the interpretation of structural and dynamic data to gain insights into the underlying biological processes. However, this analysis becomes increasingly challenging due to the complexity of the generated systems with a large number of individual runs, ranging from hundreds to thousands of trajectories. This massive increase in raw simulation data creates additional processing and visualization challenges. Effective visualization techniques play a vital role in facilitating the analysis and interpretation of molecular dynamics simulations. In this paper, we focus mainly on the techniques and tools that can be used for visualization of molecular dynamics simulations, among which we highlight the few approaches used specifically for this purpose, discussing their advantages and limitations, and addressing the future challenges of molecular dynamics visualization.
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Affiliation(s)
- Hayet Belghit
- Université de Reims Champagne-Ardenne, CNRS, MEDYC, Reims, France
| | - Mariano Spivak
- Université Paris Cité, CNRS, Laboratoire de Biochimie Théorique, Paris, France
| | - Manuel Dauchez
- Université de Reims Champagne-Ardenne, CNRS, MEDYC, Reims, France
| | - Marc Baaden
- Université Paris Cité, CNRS, Laboratoire de Biochimie Théorique, Paris, France
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2
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van der Pol RI, Brinkmann BW, Sevink GJA. Analyzing Lipid Membrane Defects via a Coarse-Grained to Triangulated Surface Map: The Role of Lipid Order and Local Curvature in Molecular Binding. J Chem Theory Comput 2024; 20:2888-2900. [PMID: 38537131 PMCID: PMC11008102 DOI: 10.1021/acs.jctc.4c00082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/14/2024] [Accepted: 03/14/2024] [Indexed: 04/10/2024]
Abstract
Lipid packing defects are known to serve as quantitative indicators for protein binding to lipid membranes. This paper presents a protocol for mapping molecular lipid detail onto a triangulated continuum leaflet representation. Besides establishing the desired forward counterpart to the existing inverse TS2CG map, this coarse-grained to triangulated surface (CG2TS) map enables straightforward extraction of the defect characteristics for any membrane geometry found in nature. We have applied our protocol to investigate the role of local curvature and varying lipid packing on the defect constant π. We find that the defect size is greatly influenced by both factors, arguing strongly against the usual assignment of a single defect constant in the case of more realistic membrane conditions. An important discovery is that lipids in the gel phase produce larger defects, or a higher π, in domains of high (local) curvature than the same lipid in a liquid phase of any curvature. This finding suggests that membranes featuring very ordered lipid packing can bind proteins via large defects in curved regions. Finally, we propose a route for estimating defect constants directly from the standard membrane properties. Identifying the precise role of composition, lipid (tail) order, and (local) curvature in defects for the irregular lipid structures that are (temporally) present in many biological processes is instrumental for obtaining fundamental insight as well as for a rational design of membrane binding targets.
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Affiliation(s)
- Rianne
W. I. van der Pol
- Leiden
Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Bregje W. Brinkmann
- Institute
of Environmental Sciences, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - G. J. Agur Sevink
- Leiden
Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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3
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Reinhard J, Starke L, Klose C, Haberkant P, Hammarén H, Stein F, Klein O, Berhorst C, Stumpf H, Sáenz JP, Hub J, Schuldiner M, Ernst R. MemPrep, a new technology for isolating organellar membranes provides fingerprints of lipid bilayer stress. EMBO J 2024; 43:1653-1685. [PMID: 38491296 PMCID: PMC11021466 DOI: 10.1038/s44318-024-00063-y] [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: 09/14/2022] [Revised: 02/16/2024] [Accepted: 02/26/2024] [Indexed: 03/18/2024] Open
Abstract
Biological membranes have a stunning ability to adapt their composition in response to physiological stress and metabolic challenges. Little is known how such perturbations affect individual organelles in eukaryotic cells. Pioneering work has provided insights into the subcellular distribution of lipids in the yeast Saccharomyces cerevisiae, but the composition of the endoplasmic reticulum (ER) membrane, which also crucially regulates lipid metabolism and the unfolded protein response, remains insufficiently characterized. Here, we describe a method for purifying organelle membranes from yeast, MemPrep. We demonstrate the purity of our ER membrane preparations by proteomics, and document the general utility of MemPrep by isolating vacuolar membranes. Quantitative lipidomics establishes the lipid composition of the ER and the vacuolar membrane. Our findings provide a baseline for studying membrane protein biogenesis and have important implications for understanding the role of lipids in regulating the unfolded protein response (UPR). The combined preparative and analytical MemPrep approach uncovers dynamic remodeling of ER membranes in stressed cells and establishes distinct molecular fingerprints of lipid bilayer stress.
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Affiliation(s)
- John Reinhard
- Saarland University, Medical Biochemistry and Molecular Biology, Homburg, Germany
- Saarland University, Preclinical Center for Molecular Signaling (PZMS), Homburg, Germany
| | - Leonhard Starke
- Saarland University, Theoretical Physics and Center for Biophysics, Saarbrücken, Germany
| | | | - Per Haberkant
- EMBL Heidelberg, Proteomics Core Facility, Heidelberg, Germany
| | | | - Frank Stein
- EMBL Heidelberg, Proteomics Core Facility, Heidelberg, Germany
| | - Ofir Klein
- Weizmann Institute of Science, Department of Molecular Genetics, Rehovot, Israel
| | - Charlotte Berhorst
- Saarland University, Medical Biochemistry and Molecular Biology, Homburg, Germany
- Saarland University, Preclinical Center for Molecular Signaling (PZMS), Homburg, Germany
| | - Heike Stumpf
- Saarland University, Medical Biochemistry and Molecular Biology, Homburg, Germany
- Saarland University, Preclinical Center for Molecular Signaling (PZMS), Homburg, Germany
| | - James P Sáenz
- Technische Universität Dresden, B CUBE, Dresden, Germany
| | - Jochen Hub
- Saarland University, Theoretical Physics and Center for Biophysics, Saarbrücken, Germany
| | - Maya Schuldiner
- Weizmann Institute of Science, Department of Molecular Genetics, Rehovot, Israel
| | - Robert Ernst
- Saarland University, Medical Biochemistry and Molecular Biology, Homburg, Germany.
- Saarland University, Preclinical Center for Molecular Signaling (PZMS), Homburg, Germany.
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4
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Qiao Q, Wei G, Song Z. Structural diversity in the membrane-bound hIAPP dimer correlated with distinct membrane disruption mechanisms. Phys Chem Chem Phys 2024; 26:7090-7102. [PMID: 38345763 DOI: 10.1039/d3cp05887e] [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: 02/23/2024]
Abstract
Amyloid deposits of the human islet amyloid polypeptide (hIAPP) have been identified in 90% of patients with type II diabetes. Cellular membranes accelerate the hIAPP fibrillation, and the integrity of membranes is also disrupted at the same time, leading to the apoptosis of β cells in pancreas. The molecular mechanism of hIAPP-induced membrane disruption, especially during the initial membrane disruption stage, has not been well understood yet. Herein, we carried out extensive all-atom molecular dynamics simulations investigating the hIAPP dimerization process in the anionic POPG membrane, to provide the detailed molecular mechanisms during the initial hIAPP aggregation stage in the membrane environment. Compared to the hIAPP monomer on the membrane, we observed not only an increase of α-helical structures, but also a substantial increase of β-sheet structures upon spontaneous dimerization. Moreover, the random coiled and α-helical dimer structures insert deep into the membrane interior with a few inter-chain contacts at the C-terminal region, while the β-sheet-rich structures reside on the membrane surface accompanied by strong inter-chain hydrophobic interactions. The coexistence of α and β structures constitutes a diverse structural ensemble of the membrane-bound hIAPP dimer. From α-helical to β-sheet structures, the degree of membrane disruption decreases gradually, and thus the membrane damage induced by random coiled and α-helical structures precedes that induced by β-sheet structures. We speculate that insertion of random coiled and α-helical structures contributes to the initial stage of membrane damage, while β-sheet structures on the membrane surface are more involved in the later stage of fibril-induced membrane disruption.
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Affiliation(s)
- Qin Qiao
- Digital Medical Research Center, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China.
- Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention, Shanghai 200032, China
| | - Guanghong Wei
- Department of Physics, State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Science (Ministry of Education), Fudan University, Shanghai 200438, China
| | - Zhijian Song
- Digital Medical Research Center, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China.
- Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention, Shanghai 200032, China
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5
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Papadopoulou P, van der Pol R, van Hilten N, van Os WL, Pattipeiluhu R, Arias-Alpizar G, Knol RA, Noteborn W, Moradi MA, Ferraz MJ, Aerts JMFG, Sommerdijk N, Campbell F, Risselada HJ, Sevink GJA, Kros A. Phase-Separated Lipid-Based Nanoparticles: Selective Behavior at the Nano-Bio Interface. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2310872. [PMID: 37988682 DOI: 10.1002/adma.202310872] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Indexed: 11/23/2023]
Abstract
The membrane-protein interface on lipid-based nanoparticles influences their in vivo behavior. Better understanding may evolve current drug delivery methods toward effective targeted nanomedicine. Previously, the cell-selective accumulation of a liposome formulation in vivo is demonstrated, through the recognition of lipid phase-separation by triglyceride lipases. This exemplified how liposome morphology and composition can determine nanoparticle-protein interactions. Here, the lipase-induced compositional and morphological changes of phase-separated liposomes-which bear a lipid droplet in their bilayer- are investigated, and the mechanism upon which lipases recognize and bind to the particles is unravelled. The selective lipolytic degradation of the phase-separated lipid droplet is observed, while nanoparticle integrity remains intact. Next, the Tryptophan-rich loop of the lipase is identified as the region with which the enzymes bind to the particles. This preferential binding is due to lipid packing defects induced on the liposome surface by phase separation. In parallel, the existing knowledge that phase separation leads to in vivo selectivity, is utilized to generate phase-separated mRNA-LNPs that target cell-subsets in zebrafish embryos, with subsequent mRNA delivery and protein expression. Together, these findings can expand the current knowledge on selective nanoparticle-protein communications and in vivo behavior, aspects that will assist to gain control of lipid-based nanoparticles.
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Affiliation(s)
- Panagiota Papadopoulou
- Department of Supramolecular & Biomaterials Chemistry, Leiden Institute of Chemistry (LIC), Leiden University, P. O. Box 9502, Leiden, 2300 RA, The Netherlands
| | - Rianne van der Pol
- Department of Supramolecular & Biomaterials Chemistry, Leiden Institute of Chemistry (LIC), Leiden University, P. O. Box 9502, Leiden, 2300 RA, The Netherlands
| | - Niek van Hilten
- Department of Supramolecular & Biomaterials Chemistry, Leiden Institute of Chemistry (LIC), Leiden University, P. O. Box 9502, Leiden, 2300 RA, The Netherlands
| | - Winant L van Os
- Department of Supramolecular & Biomaterials Chemistry, Leiden Institute of Chemistry (LIC), Leiden University, P. O. Box 9502, Leiden, 2300 RA, The Netherlands
| | - Roy Pattipeiluhu
- Department of Supramolecular & Biomaterials Chemistry, Leiden Institute of Chemistry (LIC), Leiden University, P. O. Box 9502, Leiden, 2300 RA, The Netherlands
| | - Gabriela Arias-Alpizar
- Department of Supramolecular & Biomaterials Chemistry, Leiden Institute of Chemistry (LIC), Leiden University, P. O. Box 9502, Leiden, 2300 RA, The Netherlands
| | - Renzo Aron Knol
- Department of Supramolecular & Biomaterials Chemistry, Leiden Institute of Chemistry (LIC), Leiden University, P. O. Box 9502, Leiden, 2300 RA, The Netherlands
| | - Willem Noteborn
- NeCEN, Leiden University, Einsteinweg 55, Leiden, 2333 AL, The Netherlands
| | - Mohammad-Amin Moradi
- Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P. O. Box 513, Eindhoven, 5600 MB, The Netherlands
| | - Maria Joao Ferraz
- Department of Medical Biochemistry, Leiden Institute of Chemistry (LIC), Leiden University, P. O. Box 9502, Leiden, 2300 RA, The Netherlands
| | | | - Nico Sommerdijk
- Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P. O. Box 513, Eindhoven, 5600 MB, The Netherlands
- Department of Medical BioSciences and Radboud Technology Center - Electron Microscopy, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | - Frederick Campbell
- Department of Supramolecular & Biomaterials Chemistry, Leiden Institute of Chemistry (LIC), Leiden University, P. O. Box 9502, Leiden, 2300 RA, The Netherlands
| | - Herre Jelger Risselada
- Department of Supramolecular & Biomaterials Chemistry, Leiden Institute of Chemistry (LIC), Leiden University, P. O. Box 9502, Leiden, 2300 RA, The Netherlands
- Department of Physics, Technical University Dortmund, 44221, Dortmund, Germany
| | - Geert Jan Agur Sevink
- Department of Biophysical Organic Chemistry, Leiden Institute of Chemistry (LIC), Leiden University, P. O. Box 9502, Leiden, 2300 RA, The Netherlands
| | - Alexander Kros
- Department of Supramolecular & Biomaterials Chemistry, Leiden Institute of Chemistry (LIC), Leiden University, P. O. Box 9502, Leiden, 2300 RA, The Netherlands
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6
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Sikdar S, Rani G, Vemparala S. Role of Lipid Packing Defects in Determining Membrane Interactions of Antimicrobial Polymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:4406-4412. [PMID: 36920370 DOI: 10.1021/acs.langmuir.3c00031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Understanding the emergence and role of lipid packing defects in the detection and subsequent partitioning of antimicrobial agents into bacterial membranes is essential for gaining insights into general antimicrobial mechanisms. Herein, using methacrylate polymers as a model platform, we investigate the effects of inclusion of various functional groups in the biomimetic antimicrobial polymer design on the aspects of lipid packing defects in model bacterial membranes. Two antimicrobial polymers are considered: ternary polymers composed of cationic, hydrophobic, and polar moieties and binary polymers with only cationic and hydrophobic moieties. We find that differing modes of insertion of these two polymers lead to different packing defects in the bacterial membrane. While insertion of both binary and ternary polymers leads to an enhanced number of deep defects in the upper leaflet, shallow defects are moderately enhanced upon interaction with ternary polymers only. We provide conclusive evidence that insertion of antimicrobial polymers in bacterial membrane is preceded by sensing of interfacial lipid packing defects. Our simulation results show that the hydrophobic groups are inserted at a single colocalized deep defect site for both binary and ternary polymers. However, the presence of polar groups in the ternary polymers use the shallow defects close to the lipid-water interface, in addition, to insert into the membrane, which leads to a more folded conformation of the ternary polymer in the membrane environment, and hence a different membrane partitioning mechanism compared to the binary polymer, which acquires an amphiphilic conformation.
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Affiliation(s)
- Samapan Sikdar
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400094, India
| | - Garima Rani
- Department of Physics and Materials Science, University of Luxembourg, Luxembourg City L-1511, Luxembourg
| | - Satyavani Vemparala
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400094, India
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7
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Qi Z, Wan M, Zhang J, Li Z. Influence of Cholesterol on the Membrane Binding and Conformation of α-Synuclein. J Phys Chem B 2023; 127:1956-1964. [PMID: 36812386 DOI: 10.1021/acs.jpcb.2c08077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The α-Synuclein (α-Syn) plays an important role in the pathology of Parkinson's disease (PD), and its oligomers and fibrils are toxic to the nervous system. As organisms age, the cholesterol content in biological membranes increases, which is a potential cause of PD. Cholesterol may affect the membrane binding of α-Syn and its abnormal aggregation, but the mechanism remains unclear. Here, we present our molecular dynamics simulation studies on the interaction between α-Syn and lipid membranes, with or without cholesterol. It is demonstrated that cholesterol provides additional hydrogen bond interaction with α-Syn; however, the coulomb interaction and hydrophobic interaction between α-Syn and lipid membranes could be weakened by cholesterol. In addition, cholesterol leads to the shrinking of lipid packing defects and the decrease of lipid fluidity, thereby shortening the membrane binding region of α-Syn. Under these multifaceted effects of cholesterol, membrane-bound α-Syn shows signs of forming a β-sheet structure, which may further induce the formation of abnormal α-Syn fibrils. These results provide important information for the understanding of membrane binding of α-Syn, and they are expected to promote the bridging between cholesterol and the pathological aggregation of α-Syn.
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Affiliation(s)
- Ziqiang Qi
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Menglin Wan
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Jun Zhang
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Zhen Li
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
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8
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Woods B, Thompson KC, Szita N, Chen S, Milanesi L, Tomas S. Confinement effect on hydrolysis in small lipid vesicles. Chem Sci 2023; 14:2616-2623. [PMID: 36908967 PMCID: PMC9993861 DOI: 10.1039/d2sc05747f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 02/05/2023] [Indexed: 02/17/2023] Open
Abstract
In living organisms most chemical reactions take place within the confines of lipid-membrane bound compartments, while confinement within the bounds of a lipid membrane is thought to be a key step in abiogenesis. In previous work we demonstrated that confinement in the aqueous cavity of a lipid vesicle affords protection against hydrolysis, a phenomenon that we term here confinement effect (C e) and that we attributed to the interaction with the lipid membrane. Here, we show that both the size and the shape of the cavity of the vesicle modulate the C e. We link this observation to the packing of the lipid following changes in membrane curvature, and formulate a mathematical model that relates the C e to the radius of a spherical vesicle and the packing parameter of the lipids. These results suggest that the shape of the compartment where a molecule is located plays a major role in controlling the chemical reactivity of non-enzymatic reactions. Moreover, the mathematical treatment we propose offers a useful tool for the design of vesicles with predictable reaction rates of the confined molecules, e.g., drug delivery vesicles with confined prodrugs. The results also show that a crude form of signal transduction, devoid of complex biological machinery, can be achieved by any external stimuli that drastically changes the structure of the membrane, like the osmotic shocks used in the present work.
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Affiliation(s)
- Ben Woods
- Department of Biological Sciences and Institute of Structural and Molecular Biology, Birkbeck, University of London Malet Street London WC1E 7HX UK
| | - Katherine C Thompson
- Department of Biological Sciences and Institute of Structural and Molecular Biology, Birkbeck, University of London Malet Street London WC1E 7HX UK
| | - Nicolas Szita
- Department of Biochemical Engineering, University College London, Bernard Katz Building Gordon Street London WC1H 0AH UK
| | - Shu Chen
- Department of Biological Sciences and Institute of Structural and Molecular Biology, Birkbeck, University of London Malet Street London WC1E 7HX UK
| | - Lilia Milanesi
- Department of Chemistry, University of the Balearic Islands Ctra. de Valldemossa, Km 7.5 07122 Palma de Mallorca Spain
| | - Salvador Tomas
- Department of Biological Sciences and Institute of Structural and Molecular Biology, Birkbeck, University of London Malet Street London WC1E 7HX UK.,Department of Chemistry, University of the Balearic Islands Ctra. de Valldemossa, Km 7.5 07122 Palma de Mallorca Spain
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9
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Tiwari A, Pradhan S, Sannigrahi A, Mahakud AK, Jha S, Chattopadhyay K, Biswas M, Saleem M. “Interplay of lipid-head group and packing defects in driving Amyloid-beta mediated myelin-like model membrane deformation”. J Biol Chem 2023; 299:104653. [PMID: 36990217 PMCID: PMC10148160 DOI: 10.1016/j.jbc.2023.104653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 02/24/2023] [Accepted: 03/21/2023] [Indexed: 03/29/2023] Open
Abstract
Accumulating evidence suggests that amyloid plaque associated myelin lipid loss as a result of elevated amyloid burden might also contribute to Alzheimer's disease. The amyloid fibrils though closely associated with lipids under physiological conditions, however, the progression of membrane remodeling events leading to lipid-fibril assembly remains unknown. Here we first reconstitute the interaction of Aβ-40 with myelin-like model membrane and show that the binding of Aβ-40 induces extensive tubulation. To look into the mechanism of membrane tubulation we chose a set of membrane conditions varying in lipid packing density and net charge that allows us to dissect the contribution of lipid specificity of Aβ-40 binding, aggregation kinetics, and subsequent changes in membrane parameters such as fluidity, diffusion, and compressibility modulus. We show that the binding of Aβ-40 depends predominantly on the lipid packing defect densities and electrostatic interactions and results in rigidification of the myelin-like model membrane during the early phase of amyloid aggregation. Furthermore, elongation of Aβ-40 into higher oligomeric and fibrillar species leads to eventual fluidization of the model membrane followed by extensive lipid membrane tubulation observed in the late phase. Taken together, our results capture mechanistic insights into snapshots of temporal dynamics of Aβ-40 - myelin-like model membrane interaction and demonstrate how short timescale, local phenomena of binding, and fibril-mediated load generation results in the consequent association of lipids with growing amyloid fibrils.
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10
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Linker S, Schellhaas C, Kamenik AS, Veldhuizen MM, Waibl F, Roth HJ, Fouché M, Rodde S, Riniker S. Lessons for Oral Bioavailability: How Conformationally Flexible Cyclic Peptides Enter and Cross Lipid Membranes. J Med Chem 2023; 66:2773-2788. [PMID: 36762908 PMCID: PMC9969412 DOI: 10.1021/acs.jmedchem.2c01837] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Indexed: 02/11/2023]
Abstract
Cyclic peptides extend the druggable target space due to their size, flexibility, and hydrogen-bonding capacity. However, these properties impact also their passive membrane permeability. As the "journey" through membranes cannot be monitored experimentally, little is known about the underlying process, which hinders rational design. Here, we use molecular simulations to uncover how cyclic peptides permeate a membrane. We show that side chains can act as "molecular anchors", establishing the first contact with the membrane and enabling insertion. Once inside, the peptides are positioned between headgroups and lipid tails─a unique polar/apolar interface. Only one of two distinct orientations at this interface allows for the formation of the permeable "closed" conformation. In the closed conformation, the peptide crosses to the lower leaflet via another "anchoring" and flipping mechanism. Our findings provide atomistic insights into the permeation process of flexible cyclic peptides and reveal design considerations for each step of the process.
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Affiliation(s)
- Stephanie
M. Linker
- Department
of Chemistry and Applied Biosciences, ETH
Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Christian Schellhaas
- Department
of Chemistry and Applied Biosciences, ETH
Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Anna S. Kamenik
- Department
of Chemistry and Applied Biosciences, ETH
Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Mac M. Veldhuizen
- Department
of Chemistry and Applied Biosciences, ETH
Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Franz Waibl
- Department
of Chemistry and Applied Biosciences, ETH
Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Hans-Jörg Roth
- Novartis
Institutes for BioMedical Research, Novartis
Pharma AG, Novartis Campus, 4056 Basel, Switzerland
| | - Marianne Fouché
- Novartis
Institutes for BioMedical Research, Novartis
Pharma AG, Novartis Campus, 4056 Basel, Switzerland
| | - Stephane Rodde
- Novartis
Institutes for BioMedical Research, Novartis
Pharma AG, Novartis Campus, 4056 Basel, Switzerland
| | - Sereina Riniker
- Department
of Chemistry and Applied Biosciences, ETH
Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
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11
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Steinkühler J, Jacobs ML, Boyd MA, Villaseñor CG, Loverde SM, Kamat NP. PEO- b-PBD Diblock Copolymers Induce Packing Defects in Lipid/Hybrid Membranes and Improve Insertion Rates of Natively Folded Peptides. Biomacromolecules 2022; 23:4756-4765. [PMID: 36318160 PMCID: PMC9667879 DOI: 10.1021/acs.biomac.2c00936] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/10/2022] [Indexed: 11/15/2022]
Abstract
Hybrid membranes assembled from biological lipids and synthetic polymers are a promising scaffold for the reconstitution and utilization of membrane proteins. Recent observations indicate that inclusion of small fractions of polymer in lipid membranes can improve protein folding and function, but the exact structural and physical changes a given polymer sequence imparts on a membrane often remain unclear. Here, we use all-atom molecular dynamics simulations to study the structure of hybrid membranes assembled from DOPC phospholipids and PEO-b-PBD diblock copolymers. We verified our computational model using new and existing experimental data and obtained a detailed picture of the polymer conformations in the lipid membrane that we can relate to changes in membrane elastic properties. We find that inclusion of low polymer fractions induces transient packing defects into the membrane. These packing defects act as insertion sites for two model peptides, and in this way, small amounts of polymer content in lipid membranes can lead to large increases in peptide insertion rates. Additionally, we report the peptide conformational space in both pure lipid and hybrid membranes. Both membranes support similar alpha helical peptide structures, exemplifying the biocompatibility of hybrid membranes.
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Affiliation(s)
- Jan Steinkühler
- Department
of Biomedical Engineering, Northwestern
University, Evanston, Illinois60208, United States
| | - Miranda L. Jacobs
- Department
of Biomedical Engineering, Northwestern
University, Evanston, Illinois60208, United States
| | - Margrethe A. Boyd
- Department
of Biomedical Engineering, Northwestern
University, Evanston, Illinois60208, United States
| | - Citlayi G. Villaseñor
- Department
of Biomedical Engineering, Northwestern
University, Evanston, Illinois60208, United States
| | - Sharon M. Loverde
- Department
of Chemistry, College of Staten Island, The City University of New York, Staten Island, New York10314, United States
| | - Neha P. Kamat
- Department
of Biomedical Engineering, Northwestern
University, Evanston, Illinois60208, United States
- Center
for Synthetic Biology, Northwestern University, Evanston, Illinois60657, United States
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12
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Rogers S, Gui L, Kovalenko A, Zoni V, Carpentier M, Ramji K, Ben Mbarek K, Bacle A, Fuchs P, Campomanes P, Reetz E, Speer NO, Reynolds E, Thiam AR, Vanni S, Nicastro D, Henne WM. Triglyceride lipolysis triggers liquid crystalline phases in lipid droplets and alters the LD proteome. J Cell Biol 2022; 221:213472. [PMID: 36112368 PMCID: PMC9485706 DOI: 10.1083/jcb.202205053] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 08/10/2022] [Accepted: 08/22/2022] [Indexed: 01/08/2023] Open
Abstract
Lipid droplets (LDs) are reservoirs for triglycerides (TGs) and sterol-esters (SEs), but how these lipids are organized within LDs and influence their proteome remain unclear. Using in situ cryo-electron tomography, we show that glucose restriction triggers lipid phase transitions within LDs generating liquid crystalline lattices inside them. Mechanistically this requires TG lipolysis, which decreases the LD's TG:SE ratio, promoting SE transition to a liquid crystalline phase. Molecular dynamics simulations reveal TG depletion promotes spontaneous TG and SE demixing in LDs, additionally altering the lipid packing of the PL monolayer surface. Fluorescence imaging and proteomics further reveal that liquid crystalline phases are associated with selective remodeling of the LD proteome. Some canonical LD proteins, including Erg6, relocalize to the ER network, whereas others remain LD-associated. Model peptide LiveDrop also redistributes from LDs to the ER, suggesting liquid crystalline phases influence ER-LD interorganelle transport. Our data suggests glucose restriction drives TG mobilization, which alters the phase properties of LD lipids and selectively remodels the LD proteome.
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Affiliation(s)
- Sean Rogers
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Long Gui
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Anastasiia Kovalenko
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Valeria Zoni
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Maxime Carpentier
- Laboratoire de Physique de l'École Normale Supérieure, École normale supérieure, Université Paris Sciences et Lettres, Centre national de la recherche scientifique, Sorbonne Université, Université de Paris, Paris, France
| | - Kamran Ramji
- Laboratoire de Physique de l'École Normale Supérieure, École normale supérieure, Université Paris Sciences et Lettres, Centre national de la recherche scientifique, Sorbonne Université, Université de Paris, Paris, France
| | - Kalthoum Ben Mbarek
- Laboratoire de Physique de l'École Normale Supérieure, École normale supérieure, Université Paris Sciences et Lettres, Centre national de la recherche scientifique, Sorbonne Université, Université de Paris, Paris, France
| | - Amelie Bacle
- Institute Jacques Monod, Centre national de la recherche scientifique, University of Paris, Paris, France
| | - Patrick Fuchs
- Laboratoire des Biomolécules, Paris, France.,Université de Paris, UFR Sciences du Vivant, Paris, France
| | - Pablo Campomanes
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Evan Reetz
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Natalie Ortiz Speer
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Emma Reynolds
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Abdou Rachid Thiam
- Laboratoire de Physique de l'École Normale Supérieure, École normale supérieure, Université Paris Sciences et Lettres, Centre national de la recherche scientifique, Sorbonne Université, Université de Paris, Paris, France
| | - Stefano Vanni
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Daniela Nicastro
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - W Mike Henne
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
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13
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Braun RJ, Swanson JMJ. Capturing the Liquid-Crystalline Phase Transformation: Implications for Protein Targeting to Sterol Ester-Rich Lipid Droplets. MEMBRANES 2022; 12:949. [PMID: 36295707 PMCID: PMC9607156 DOI: 10.3390/membranes12100949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/23/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Lipid droplets are essential organelles that store and traffic neutral lipids. The phospholipid monolayer surrounding their neutral lipid core engages with a highly dynamic proteome that changes according to cellular and metabolic conditions. Recent work has demonstrated that when the abundance of sterol esters increases above a critical concentration, such as under conditions of starvation or high LDL exposure, the lipid droplet core can undergo an amorphous to liquid-crystalline phase transformation. Herein, we study the consequences of this transformation on the physical properties of lipid droplets that are thought to regulate protein association. Using simulations of different sterol-ester concentrations, we have captured the liquid-crystalline phase transformation at the molecular level, highlighting the alignment of sterol esters in alternating orientations to form concentric layers. We demonstrate how ordering in the core permeates into the neutral lipid/phospholipid interface, changing the magnitude and nature of neutral lipid intercalation and inducing ordering in the phospholipid monolayer. Increased phospholipid packing is concomitant with altered surface properties, including smaller area per phospholipid and substantially reduced packing defects. Additionally, the ordering of sterol esters in the core causes less hydration in more ordered regions. We discuss these findings in the context of their expected consequences for preferential protein recruitment to lipid droplets under different metabolic conditions.
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14
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van Hilten N, Stroh KS, Risselada HJ. Efficient Quantification of Lipid Packing Defect Sensing by Amphipathic Peptides: Comparing Martini 2 and 3 with CHARMM36. J Chem Theory Comput 2022; 18:4503-4514. [PMID: 35709386 PMCID: PMC9281404 DOI: 10.1021/acs.jctc.2c00222] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In biological systems, proteins can be attracted to curved or stretched regions of lipid bilayers by sensing hydrophobic defects in the lipid packing on the membrane surface. Here, we present an efficient end-state free energy calculation method to quantify such sensing in molecular dynamics simulations. We illustrate that lipid packing defect sensing can be defined as the difference in mechanical work required to stretch a membrane with and without a peptide bound to the surface. We also demonstrate that a peptide's ability to concurrently induce excess leaflet area (tension) and elastic softening─a property we call the "characteristic area of sensing" (CHAOS)─and lipid packing sensing behavior are in fact two sides of the same coin. In essence, defect sensing displays a peptide's propensity to generate tension. The here-proposed mechanical pathway is equally accurate yet, computationally, about 40 times less costly than the commonly used alchemical pathway (thermodynamic integration), allowing for more feasible free energy calculations in atomistic simulations. This enabled us to directly compare the Martini 2 and 3 coarse-grained and the CHARMM36 atomistic force fields in terms of relative binding free energies for six representative peptides including the curvature sensor ALPS and two antiviral amphipathic helices (AH). We observed that Martini 3 qualitatively reproduces experimental trends while producing substantially lower (relative) binding free energies and shallower membrane insertion depths compared to atomistic simulations. In contrast, Martini 2 tends to overestimate (relative) binding free energies. Finally, we offer a glimpse into how our end-state-based free energy method can enable the inverse design of optimal lipid packing defect sensing peptides when used in conjunction with our recently developed evolutionary molecular dynamics (Evo-MD) method. We argue that these optimized defect sensors─aside from their biomedical and biophysical relevance─can provide valuable targets for the development of lipid force fields.
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Affiliation(s)
- Niek van Hilten
- Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands
| | - Kai Steffen Stroh
- Department of Physics, Technical University Dortmund, Dortmund 44221, Germany.,Institute for Theoretical Physics, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Herre Jelger Risselada
- Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands.,Department of Physics, Technical University Dortmund, Dortmund 44221, Germany.,Institute for Theoretical Physics, Georg-August-University Göttingen, Göttingen 37077, Germany
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15
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Kim S, Swanson JMJ, Voth GA. Computational Studies of Lipid Droplets. J Phys Chem B 2022; 126:2145-2154. [PMID: 35263109 PMCID: PMC8957551 DOI: 10.1021/acs.jpcb.2c00292] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/26/2022] [Indexed: 02/05/2023]
Abstract
Lipid droplets (LDs) are intracellular organelles whose primary function is energy storage. Known to emerge from the endoplasmic reticulum (ER) bilayer, LDs have a unique structure with a core consisting of neutral lipids, triacylglycerol (TG) or sterol esters (SE), surrounded by a phospholipid (PL) monolayer and decorated by proteins that come and go throughout their complex lifecycle. In this Feature Article, we review recent developments in computational studies of LDs, a rapidly growing area of research. We highlight how molecular dynamics (MD) simulations have provided valuable molecular-level insight into LD targeting and LD biogenesis. Additionally, we review the physical properties of TG from different force fields compared with experimental data. Possible future directions and challenges are discussed.
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Affiliation(s)
- Siyoung Kim
- Pritzker
School of Molecular Engineering, University
of Chicago, Chicago, Illinois 60637, United States
| | - Jessica M. J. Swanson
- Department
of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Gregory A. Voth
- Department
of Chemistry, Chicago Center for Theoretical Chemistry, James Franck
Institute, and Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois 60637, United States
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16
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Sikdar S, Banerjee M, Vemparala S. Role of Disulphide Bonds in Membrane Partitioning of a Viral Peptide. J Membr Biol 2022; 255:129-142. [PMID: 35218393 PMCID: PMC8881898 DOI: 10.1007/s00232-022-00218-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 02/02/2022] [Indexed: 01/22/2023]
Abstract
The importance of disulphide bond in mediating viral peptide entry into host cells is well known. In the present work, we elucidate the role of disulphide (SS) bond in partitioning mechanism of membrane-active Hepatitis A Virus-2B (HAV-2B) peptide, which harbours three cysteine residues promoting formation of multiple SS-bonded states. The inclusion of SS-bond not only results in a compact conformation but also induces distorted α-helical hairpin geometry in comparison to SS-free state. Owing to these, the hydrophobic residues get buried, restricting the insertion of SS-bonded HAV-2B peptide into lipid packing defects and thus the partitioning of the peptide is completely or partly abolished. In this way, the disulphide bond can potentially regulate the partitioning of HAV-2B peptide such that the membrane remodelling effects of this viral peptide are significantly reduced. The current findings may have potential implications in drug designing, targeting the HAV-2B protein by promoting disulphide bond formation within its membrane-active region.
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Affiliation(s)
- Samapan Sikdar
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai, 600113, India. .,Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400094, India.
| | - Manidipa Banerjee
- Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, Hauz Khas, New Delhi, 110016, India.
| | - Satyavani Vemparala
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai, 600113, India. .,Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400094, India.
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17
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Singhal A, Agur Sevink GJ. The role of size and nature in nanoparticle binding to a model lung membrane: an atomistic study. NANOSCALE ADVANCES 2021; 3:6635-6648. [PMID: 36132649 PMCID: PMC9417560 DOI: 10.1039/d1na00578b] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 09/16/2021] [Indexed: 05/09/2023]
Abstract
Understanding the uptake of nanoparticles (NPs) by different types of cellular membranes plays a pivotal role in the design of NPs for medical applications and in avoiding adverse effects that result in nanotoxicity. Yet, the role of key design parameters, such as the bare NP material, NP size and surface reactivity, and the nature of NP coatings, in membrane remodelling and uptake mechanisms is still very poorly understood, particularly towards the lower range of NP dimensions that are beyond the experimental imaging resolution. The same can be said about the role of a particular membrane composition. Here, we systematically employ biased and unbiased molecular dynamics simulations to calculate the binding energy for three bare materials (Ag/SiO2/TiO2) and three NP sizes (1/3/5 nm diameter) with a representative lung surfactant membrane, and to study their binding kinetics. The calculated binding energies show that irrespective of size, Ag nanoparticles bind very strongly to the bilayer, while the NPs made of SiO2 or TiO2 experience very low to no binding. The unbiased simulations provide insight into how the NPs and membrane affect each other in terms of the solvent-accessible surface area (SASA) of the NPs and the defect types and fluidity of the membrane. Using these systematic fine-grained results in coarsening procedures will pave the way for simulations considering NP sizes that are well beyond the membrane thickness, i.e. closer to experimental dimensions, for which different binding characteristics and more significant membrane remodelling are expected.
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Affiliation(s)
- Ankush Singhal
- Leiden Institute of Chemistry, Leiden University P.O. Box 9502 2300 RA Leiden The Netherlands
| | - G J Agur Sevink
- Leiden Institute of Chemistry, Leiden University P.O. Box 9502 2300 RA Leiden The Netherlands
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18
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François-Martin C, Bacle A, Rothman JE, Fuchs PFJ, Pincet F. Cooperation of Conical and Polyunsaturated Lipids to Regulate Initiation and Processing of Membrane Fusion. Front Mol Biosci 2021; 8:763115. [PMID: 34746239 PMCID: PMC8566721 DOI: 10.3389/fmolb.2021.763115] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 09/23/2021] [Indexed: 12/03/2022] Open
Abstract
The shape of lipids has long been suspected to be a critical determinant for the control of membrane fusion. To experimentally test this assertion, we used conical and malleable lipids and measured their influence on the fusion kinetics. We found that, as previously suspected, both types of lipids accelerate fusion. However, the implicated molecular mechanisms are strikingly different. Malleable lipids, with their ability to change shape with low energy cost, favor fusion by decreasing the overall activation energy. On the other hand, conical lipids, with their small polar head relative to the area occupied by the hydrophobic chains, tend to make fusion less energetically advantageous because they tend to migrate towards the most favorable lipid leaflet, hindering fusion pore opening. They could however facilitate fusion by generating hydrophobic defects on the membranes; this is suggested by the similar trend observed between the experimental rate of fusion nucleation and the surface occupied by hydrophobic defects obtained by molecular simulations. The synergy of dual-process, activation energy and nucleation kinetics, could facilitate membrane fusion regulation in vivo.
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Affiliation(s)
- Claire François-Martin
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, CNRS, Université PSL, Sorbonne Université, Université de Paris, Paris, France
| | - Amélie Bacle
- Laboratoire Coopératif "Lipotoxicity and Channelopathies-ConicMeds", Université de Poitiers, Poitiers, France
| | - James E Rothman
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, United States.,Nanobiology Institute, Yale School of Medicine, West Haven, CT, United States
| | - Patrick F J Fuchs
- Laboratoire des Biomolécules (LBM), CNRS, Ecole Normale Supérieure, Sorbonne Université, PSL Research University, Paris, France.,UFR Sciences Du Vivant, Université de Paris, Paris, France
| | - Frédéric Pincet
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, CNRS, Université PSL, Sorbonne Université, Université de Paris, Paris, France
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19
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Sikdar S, Banerjee M, Vemparala S. Effect of cholesterol on the membrane partitioning dynamics of hepatitis A virus-2B peptide. SOFT MATTER 2021; 17:7963-7977. [PMID: 34378608 DOI: 10.1039/d1sm01019k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Understanding viral peptide detection and partitioning and the subsequent host membrane composition-based response is essential for gaining insights into the viral mechanism. Here, we probe the crucial role of the presence of membrane lipid packing defects, depending on the membrane composition, in allowing the viral peptide belonging to C-terminal Hepatitis A Virus-2B (HAV-2B) to detect, attach and subsequently partition into host cell membrane mimics. Using molecular dynamics simulations, we conclusively show that the hydrophobic residues in the viral peptide detect transiently present lipid packing defects, insert themselves into such defects, form anchor points and facilitate the partitioning of the peptide, thereby inducing membrane disruption. We also show that the presence of cholesterol significantly alters such lipid packing defects, both in size and in number, thus mitigating the partitioning of the membrane active viral peptide into cholesterol-rich membranes. Our results are in excellent agreement with previously published experimental data and further explain the role of lipid defects in understanding such data. These results show differential ways in which the presence and absence of cholesterol can alter the permeability of the host membranes to the membrane active peptide component of HAV-2B virus, via lipid packing defects, and can possibly be a part of the general membrane detection mechanism for viroporins.
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Affiliation(s)
- Samapan Sikdar
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India.
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20
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Rogers JR, Espinoza Garcia G, Geissler PL. Membrane hydrophobicity determines the activation free energy of passive lipid transport. Biophys J 2021; 120:3718-3731. [PMID: 34302793 PMCID: PMC8456290 DOI: 10.1016/j.bpj.2021.07.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 07/07/2021] [Accepted: 07/19/2021] [Indexed: 12/16/2022] Open
Abstract
The collective behavior of lipids with diverse chemical and physical features determines a membrane's thermodynamic properties. Yet, the influence of lipid physicochemical properties on lipid dynamics, in particular interbilayer transport, remains underexplored. Here, we systematically investigate how the activation free energy of passive lipid transport depends on lipid chemistry and membrane phase. Through all-atom molecular dynamics simulations of 11 chemically distinct glycerophospholipids, we determine how lipid acyl chain length, unsaturation, and headgroup influence the free energy barriers for two elementary steps of lipid transport: lipid desorption, which is rate limiting, and lipid insertion into a membrane. Consistent with previous experimental measurements, we find that lipids with longer, saturated acyl chains have increased activation free energies compared to lipids with shorter, unsaturated chains. Lipids with different headgroups exhibit a range of activation free energies; however, no clear trend based solely on chemical structure can be identified, mirroring difficulties in the interpretation of previous experimental results. Compared to liquid-crystalline phase membranes, gel phase membranes exhibit substantially increased free energy barriers. Overall, we find that the activation free energy depends on a lipid's local hydrophobic environment in a membrane and that the free energy barrier for lipid insertion depends on a membrane's interfacial hydrophobicity. Both of these properties can be altered through changes in lipid acyl chain length, lipid headgroup, and membrane phase. Thus, the rate of lipid transport can be tuned through subtle changes in local membrane composition and order, suggesting an unappreciated role for nanoscale membrane domains in regulating cellular lipid dynamics.
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Affiliation(s)
- Julia R Rogers
- Department of Chemistry, University of California Berkeley, Berkeley, California.
| | | | - Phillip L Geissler
- Department of Chemistry, University of California Berkeley, Berkeley, California; Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California.
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21
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Mahajan M, Bharambe N, Shang Y, Lu B, Mandal A, Madan Mohan P, Wang R, Boatz JC, Manuel Martinez Galvez J, Shnyrova AV, Qi X, Buck M, van der Wel PCA, Ramachandran R. NMR identification of a conserved Drp1 cardiolipin-binding motif essential for stress-induced mitochondrial fission. Proc Natl Acad Sci U S A 2021; 118:e2023079118. [PMID: 34261790 PMCID: PMC8307854 DOI: 10.1073/pnas.2023079118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mitochondria form tubular networks that undergo coordinated cycles of fission and fusion. Emerging evidence suggests that a direct yet unresolved interaction of the mechanoenzymatic GTPase dynamin-related protein 1 (Drp1) with mitochondrial outer membrane-localized cardiolipin (CL), externalized under stress conditions including mitophagy, catalyzes essential mitochondrial hyperfragmentation. Here, using a comprehensive set of structural, biophysical, and cell biological tools, we have uncovered a CL-binding motif (CBM) conserved between the Drp1 variable domain (VD) and the unrelated ADP/ATP carrier (AAC/ANT) that intercalates into the membrane core to effect specific CL interactions. CBM mutations that weaken VD-CL interactions manifestly impair Drp1-dependent fission under stress conditions and induce "donut" mitochondria formation. Importantly, VD membrane insertion and GTP-dependent conformational rearrangements mediate only transient CL nonbilayer topological forays and high local membrane constriction, indicating that Drp1-CL interactions alone are insufficient for fission. Our studies establish the structural and mechanistic bases of Drp1-CL interactions in stress-induced mitochondrial fission.
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Affiliation(s)
- Mukesh Mahajan
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
| | - Nikhil Bharambe
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
| | - Yutong Shang
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
| | - Bin Lu
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
| | - Abhishek Mandal
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Pooja Madan Mohan
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
| | - Rihua Wang
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
| | - Jennifer C Boatz
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Juan Manuel Martinez Galvez
- Instituto Biofisika and Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa, Spain
| | - Anna V Shnyrova
- Instituto Biofisika and Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa, Spain
| | - Xin Qi
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Matthias Buck
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH 44106
| | - Patrick C A van der Wel
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Zernike Institute for Advanced Materials, University of Groningen, 9700 AB Groningen, The Netherlands
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106;
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH 44106
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22
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Kim S, Oh MI, Swanson JMJ. Stressed Lipid Droplets: How Neutral Lipids Relieve Surface Tension and Membrane Expansion Drives Protein Association. J Phys Chem B 2021; 125:5572-5586. [PMID: 34014091 PMCID: PMC8796793 DOI: 10.1021/acs.jpcb.1c01795] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Lipid droplets (LDs) are intracellular storage organelles composed of neutral lipids, such as triacylglycerol (TG), surrounded by a phospholipid (PL) monolayer decorated with specific proteins. Herein, we investigate the mechanism of protein association during LD and bilayer membrane expansion. We find that the neutral lipids play a dynamic role in LD expansion by further intercalating with the PL monolayer to create more surface-oriented TG molecules (SURF-TG). This interplay both reduces high surface tension incurred during LD budding or growth and also creates expansion-specific surface features for protein recognition. We then show that the autoinhibitory (AI) helix of CTP:phosphocholine cytidylyltransferase, a protein known to target expanding monolayers and bilayers, preferentially associates with large packing defects in a sequence-specific manner. Despite the presence of three phenylalanines, the initial binding with bilayers is predominantly mediated by the sole tryptophan due to its preference for membrane interfaces. Subsequent association is dependent on the availability of large, neighboring defects that can accommodate the phenylalanines, which are more probable in the stressed systems. Tryptophan, once fully associated, preferentially interacts with the glycerol moiety of SURF-TG in LDs. The calculation of AI binding free energy, hydrogen bonding and depth analysis, and in silico mutation experiments support the findings. Hence, SURF-TG can both reduce surface tension and mediate protein association, facilitating class II protein recruitment during LD expansion.
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Affiliation(s)
- Siyoung Kim
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, 60637 USA
| | - Myong In Oh
- Department of Chemistry, University of Utah, Salt Lake City, UT, 84112 USA
| | - Jessica M. J. Swanson
- Department of Chemistry, University of Utah, Salt Lake City, UT, 84112 USA
- Corresponding author: Jessica M. J. Swanson,
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23
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Zoni V, Campomanes P, Vanni S. Investigating the structural properties of hydrophobic solvent-rich lipid bilayers. SOFT MATTER 2021; 17:5329-5335. [PMID: 33969832 PMCID: PMC8170560 DOI: 10.1039/d0sm02270e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 04/27/2021] [Indexed: 06/12/2023]
Abstract
In vitro reconstitutions of lipid membranes have proven to be an indispensable tool to rationalize their molecular complexity and to understand their role in countless cellular processes. However, amongst the various techniques used to reconstitute lipid bilayers in vitro, several approaches are not solvent-free, but rather contain residual hydrophobic solvents in between the two bilayer leaflets, generally as a consequence of the procedure used to generate the bilayer. To what extent the presence of these hydrophobic solvents modifies bilayer properties with respect to native, solvent-free, conditions remains an open question that has important implications for the appropriate interpretation of numerous experimental observations. Here, we thorouhgly characterize hydrophobic solvent-rich lipid bilayers using atomistic molecular dynamics simulations. Our data indicate that while the presence of hydrophobic solvents at high concentrations, such as hexadecane, has a significant effect on membrane thickness, their effects on surface properties, membrane order and lateral stress are quite moderate. Our results corroborate the validity of in vitro approaches as model systems for the investigations of biological membranes but raise a few cautionary aspects that must be considered when investigating specific membrane properties.
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Affiliation(s)
- Valeria Zoni
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.
| | - Pablo Campomanes
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.
| | - Stefano Vanni
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.
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24
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Manna M, Murarka RK. Polyunsaturated Fatty Acid Modulates Membrane-Bound Monomeric α-Synuclein by Modulating Membrane Microenvironment through Preferential Interactions. ACS Chem Neurosci 2021; 12:675-688. [PMID: 33538574 DOI: 10.1021/acschemneuro.0c00694] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
There is ample evidence that both native functions and pathogenic aggregation of α-synuclein are intimately dependent on lipid interactions and fatty acid type; the regulatory mechanism however remains unclear. In the present work, using extensive atomistic molecular dynamics simulations and enhanced-sampling, we have focused on exploring the mechanism of fatty acid dependent regulation of monomeric α-Syn100 in a native synaptic vesicle-like membrane. Our results show that α-Syn100 spontaneously binds to the membrane through its N-terminal region (residues 1-34), where the depth of membrane insertion, the structure, and orientation of the membrane-bound α-Syn100 and its impact on membrane structure are modulated by docosahexaenoic acid (DHA). DHA is a polyunsaturated fatty acid abundantly found in the brain and known to promote the oligomerization of α-synuclein. We found that DHA exhibits marked propensity to interact with monomeric α-Syn100 and modulates the microenvironment of the protein by preferentially sorting DHA-containing phospholipids, depleting other phospholipids and cholesterol as well as increasing the proportion of anionic to neutral lipids in the immediate vicinity of the protein. Owing to the unique conformational flexibility, DHA chains form more lipid-packing defects in the membrane and efficiently coat the membrane-embedded surface of the protein, compared to the saturated and monounsaturated fatty acids. DHA thus makes the bilayer more amiable to protein adsorption and less prone to α-synuclein-induced perturbation associated with cytotoxicity. Indeed, in the absence of DHA, we observed significant thinning of the local bilayer membrane induced by α-Syn100. Though α-Syn100 is predominantly α-helical in membranes studied here, in the presence of DHA we observe formation of β-sheet/β-strands in the C-terminal region (residues 35-100) of α-Syn100, which is extended out from the membrane surface. Notably, DHA induces β structure in the NAC domain of α-Syn100 and promotes extended conformations as well as large solvent exposure of this hydrophobic domain, properties that are known to facilitate self-assembly of α-synuclein. To the best of our knowledge, this study for the first time provides the atomistic insights into DHA-induced regulatory mechanism of monomeric α-synuclein, having implications in protein structure and its physiological/pathological functions.
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Affiliation(s)
- Moutusi Manna
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh 462 066, India
- Applied Phycology and Biotechnology Division, CSIR−Central Salt & Marine Chemicals Research Institute (CSIR−CSMCRI), Gijubhai Badheka Marg, Bhavnagar, Gujarat 364002, India
| | - Rajesh K. Murarka
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh 462 066, India
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In Silico Prediction of the Binding, Folding, Insertion, and Overall Stability of Membrane-Active Peptides. Methods Mol Biol 2021; 2315:161-182. [PMID: 34302676 DOI: 10.1007/978-1-0716-1468-6_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Membrane-active peptides (MAPs) are short-length peptides used for potential biomedical applications in diagnostic imaging of tissues, targeted drug delivery, gene delivery, and antimicrobials and antibiotics. The broad appeal of MAPs is that they are infinitely variable, relatively low cost, and biocompatible. However, experimentally characterizing the specific properties of a MAP or its many variants is a low-resolution and potentially time-consuming endeavor; molecular dynamics (MD) simulations have emerged as an invaluable tool in identifying the biophysical interactions that are fundamental to the function of MAPs. In this chapter, a step-by-step approach to discreetly model the binding, folding, and insertion of a membrane-active peptide to a model lipid bilayer using MD simulations is described. Detailed discussion is devoted to the critical aspects of running these types of simulations: prior knowledge of the system, understanding the strengths and weaknesses of molecular mechanics force fields, proper construction and equilibration of the system, realistically estimating both experimental and computational timescales, and leveraging analysis to make direct comparisons to experimental results as often as possible.
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26
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Heymich ML, Friedlein U, Trollmann M, Schwaiger K, Böckmann RA, Pischetsrieder M. Generation of antimicrobial peptides Leg1 and Leg2 from chickpea storage protein, active against food spoilage bacteria and foodborne pathogens. Food Chem 2020; 347:128917. [PMID: 33465691 DOI: 10.1016/j.foodchem.2020.128917] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 12/19/2022]
Abstract
Contamination with bacteria leads to food waste and foodborne diseases with severe consequences for the environment and human health. Aiming to reduce food spoilage and infection, the present study developed novel highly active food-grade antimicrobial peptides affecting a wide range of bacteria. After extraction from chickpea, the storage protein legumin was hydrolyzed by the digestive protease chymotrypsin. Subsequent analysis by ultrahigh-performance micro-liquid chromatography-triple quadrupole time-of-flight tandem mass spectrometry determined the resulting peptide profiles. Virtual screening identified 21 potential antimicrobial peptides in the hydrolysates. Among those, the peptides Leg1 (RIKTVTSFDLPALRFLKL) and Leg2 (RIKTVTSFDLPALRWLKL) exhibited antimicrobial activity against 16 different bacteria, including pathogens, spoilage-causing bacteria and two antibiotic-resistant strains. Leg1/Leg2 showed minimum inhibitory concentrations (MIC) down to 15.6 µmol/L and were thus 10-1,000-fold more active compared to conventional food preservatives. Moreover, Leg1 and Leg2 showed bactericidal activity in contrast to the bacteriostatic activity of conventional preservatives.
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Affiliation(s)
- Marie-Louise Heymich
- Food Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Nikolaus-Fiebiger-Str. 10, 91058 Erlangen, Germany.
| | - Ulrike Friedlein
- Chair of Food Safety, Faculty of Veterinary Medicine, Ludwig Maximilian University of Munich, Schönleutnerstr. 8, 85764 Oberschleißheim Germany.
| | - Marius Trollmann
- Computational Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstr. 5, 91058 Erlangen, Germany.
| | - Karin Schwaiger
- Chair of Food Safety, Faculty of Veterinary Medicine, Ludwig Maximilian University of Munich, Schönleutnerstr. 8, 85764 Oberschleißheim Germany.
| | - Rainer A Böckmann
- Computational Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstr. 5, 91058 Erlangen, Germany.
| | - Monika Pischetsrieder
- Food Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Nikolaus-Fiebiger-Str. 10, 91058 Erlangen, Germany.
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27
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Tripathy M, Thangamani S, Srivastava A. Three-Dimensional Packing Defects in Lipid Membrane as a Function of Membrane Order. J Chem Theory Comput 2020; 16:7800-7816. [PMID: 33226805 DOI: 10.1021/acs.jctc.0c00609] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Lipid membrane packing defects are considered to be an essential parameter that regulates specific membrane binding of several peripheral proteins. In the absence of direct experimental characterization, lipid packing defects and their role in the binding of peripheral proteins are generally investigated through computational studies, which have been immensely successful in unraveling the key steps of the membrane-binding process. However, packing defects are calculated using two-dimensional (2D) projections and the crucial information on their depths is generally overlooked. Here, we present a simple yet computationally efficient algorithm, which identifies these defects in three dimensions. We validate the algorithm on a number of model membrane systems that are previously studied using 2D defect calculations and find that the defect size and the defect depth may not always be directly correlated. We employ the algorithm to understand the nature of packing defects in flat bilayer membranes exhibiting liquid-ordered (Lo), liquid-disordered (Ld), and co-existing (Lo/Ld) phases. Our results indicate the presence of shallower, smaller, and spatially localized defects in the Lo phase membranes as compared to the defects in Ld and mixed Lo/Ld phase membranes. Such analyses can elucidate the molecular-scale mechanisms that drive the preferential localization of certain proteins to either of the liquid phases or their interface. We also analyze the membrane sensing and anchoring process of a peptide in terms of the three-dimensional defects, which provides additional insights into the process with respect to depth distributions across the bilayer leaflets.
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Affiliation(s)
- Madhusmita Tripathy
- Molecular Biophysics Unit, Indian Institute of Science-Bangalore, C.V. Raman Road, Bangalore, Karnataka 560012, India
| | - Subasini Thangamani
- Molecular Biophysics Unit, Indian Institute of Science-Bangalore, C.V. Raman Road, Bangalore, Karnataka 560012, India
| | - Anand Srivastava
- Molecular Biophysics Unit, Indian Institute of Science-Bangalore, C.V. Raman Road, Bangalore, Karnataka 560012, India
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28
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Kim S, Swanson JMJ. The Surface and Hydration Properties of Lipid Droplets. Biophys J 2020; 119:1958-1969. [PMID: 33120015 PMCID: PMC7732727 DOI: 10.1016/j.bpj.2020.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 09/16/2020] [Accepted: 10/07/2020] [Indexed: 11/24/2022] Open
Abstract
Lipid droplets (LDs) are energy storage organelles composed of neutral lipids, such as triacylglycerol (TG) and sterol esters, surrounded by a phospholipid (PL) monolayer. Their central role in metabolism, complex life cycle, and unique lipid monolayer surface have garnered great attention over the last decade. In this article, results from the largest and longest all-atom simulations to date suggest that 5-8% of the LD surface is occupied by TG molecules, a number that exceeds the maximal solubility reported for TGs in PL bilayers (2.8%). Two distinct classes of TG molecules that interact with the LD monolayer are found. Those at the monolayer surface (SURF-TG) are ordered like PLs with the glycerol moiety exposed to water, creating a significant amount of chemically unique packing defects, and the acyl chains extended toward the LD center. In contrast, the TGs that intercalate just into the PL tail region (CORE-TG) are disordered and increase the amount of PL packing defects and the PL tail order. The degree of interdigitation caused by CORE-TG is stable and determines the width of the TG-PL overlap, whereas that caused by SURF-TG fluctuates and is highly correlated with the area per PL or the expansion of the monolayer. Thus, when the supply of PLs is limited, SURF-TG may reduce surface tension by behaving as a secondary membrane component. The hydration properties of the simulated LD systems demonstrate ∼10 times more water in the LD core than previously reported. Collectively, the reported surface and hydration properties are expected to play a direct role in the mechanisms by which proteins target and interact with LDs.
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Affiliation(s)
- Siyoung Kim
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois; and
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29
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Rogers JR, Geissler PL. Breakage of Hydrophobic Contacts Limits the Rate of Passive Lipid Exchange between Membranes. J Phys Chem B 2020; 124:5884-5898. [DOI: 10.1021/acs.jpcb.0c04139] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Julia R. Rogers
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Phillip L. Geissler
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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30
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van Hilten N, Stroh KS, Risselada HJ. Membrane Thinning Induces Sorting of Lipids and the Amphipathic Lipid Packing Sensor (ALPS) Protein Motif. Front Physiol 2020; 11:250. [PMID: 32372966 PMCID: PMC7177014 DOI: 10.3389/fphys.2020.00250] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/05/2020] [Indexed: 12/16/2022] Open
Abstract
Heterogeneities (e.g., membrane proteins and lipid domains) and deformations (e.g., highly curved membrane regions) in biological lipid membranes cause lipid packing defects that may trigger functional sorting of lipids and membrane-associated proteins. To study these phenomena in a controlled and efficient way within molecular simulations, we developed an external field protocol that artificially enhances packing defects in lipid membranes by enforcing local thinning of a flat membrane region. For varying lipid compositions, we observed strong thinning-induced depletion or enrichment, depending on the lipid's intrinsic shape and its effect on a membrane's elastic modulus. In particular, polyunsaturated and lysolipids are strongly attracted to regions high in packing defects, whereas phosphatidylethanolamine (PE) lipids and cholesterol are strongly repelled from it. Our results indicate that externally imposed changes in membrane thickness, area, and curvature are underpinned by shared membrane elastic principles. The observed sorting toward the thinner membrane region is in line with the sorting expected for a positively curved membrane region. Furthermore, we have demonstrated that the amphipathic lipid packing sensor (ALPS) protein motif, a known curvature and packing defect sensor, is effectively attracted to thinner membrane regions. By extracting the force that drives amphipathic molecules toward the thinner region, our thinning protocol can directly quantify and score the lipid packing sensing of different amphipathic molecules. In this way, our protocol paves the way toward high-throughput exploration of potential defect- and curvature-sensing motifs, making it a valuable addition to the molecular simulation toolbox.
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Affiliation(s)
- Niek van Hilten
- Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
| | - Kai Steffen Stroh
- Institute for Theoretical Physics, Georg August University Göttingen, Göttingen, Germany
| | - Herre Jelger Risselada
- Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands.,Institute for Theoretical Physics, Georg August University Göttingen, Göttingen, Germany
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31
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Vanni S, Riccardi L, Palermo G, De Vivo M. Structure and Dynamics of the Acyl Chains in the Membrane Trafficking and Enzymatic Processing of Lipids. Acc Chem Res 2019; 52:3087-3096. [PMID: 31364837 DOI: 10.1021/acs.accounts.9b00134] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The regulatory chemical mechanisms of lipid trafficking and degradation are involved in many pathophysiological processes, being implicated in severe pain, inflammation, and cancer. In addition, the processing of lipids is also relevant for industrial and environmental applications. However, there is poor understanding of the chemical features that control lipid membrane trafficking and allow lipid-degrading enzymes to efficiently select and hydrolyze specific fatty acids from a complex cellular milieu of bioactive lipids. This is particularly true for lipid acyl chains, which have diverse structures that can critically affect the many complex reactions needed to elongate, desaturate, or transport fatty acids. Building upon our own contributions in this field, we will discuss how molecular simulations, integrated with experimental evidence, have revealed that the structure and dynamics of the lipid tail are actively involved in modulating membrane trafficking at cellular organelles, and enzymatic reactions at cell membranes. Further evidence comes from recent crystal structures of lipid receptors and remodeling enzymes. Taken together, these recent works have identified those structural features of the lipid acyl chain that are crucial for the regioselectivity and stereospecificity of essential desaturation reactions. In this context, we will first illustrate how atomistic and coarse-grained simulations have elucidated the structure-function relationships between the chemical composition of the lipid's acyl chains and the molecular properties of lipid bilayers. Particular emphasis will be given to the prominent chemical role of the number of double carbon-carbon bonds along the lipid acyl chain, that is, discriminating between saturated, monounsaturated, and polyunsaturated lipids. Different levels of saturation in fatty acid molecules dramatically influence the biophysical properties of lipid assemblies and their interaction with proteins. We will then discuss the processing of lipids by membrane-bound enzymes. Our focus will be on lipids such as anandamide and 2-arachidonoylglycerol. These are the main molecules that act as neurotransmitters in the endocannabinoid system. Specifically, recent findings indicate a crucial interplay between the level of saturation of the lipid tail, its energetically and sterically favored conformations, and the hydrophobic accessory cavities in lipid-degrading enzymes, which help form catalytically active conformations of the selected substrate. This Account will emphasize how the specific chemical structure of acyl chains affects the molecular mechanisms for modulating membrane trafficking and selective hydrolysis. The results examined here show that, by using molecular simulations to investigate lipid plasticity and substrate flexibility, researchers can enrich their interpretation of experimental results about the structure-function relationships of lipids. This could positively impact chemical and biological studies in the field and ultimately support protein engineering studies and structure-based drug discovery to target lipid-processing enzymes.
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Affiliation(s)
- Stefano Vanni
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
- Université Côte d’Azur, CNRS, IPMC, 06560 Valbonne, France
| | - Laura Riccardi
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
| | - Giulia Palermo
- Department of Bioengineering, University of California Riverside, Riverside, California 92521, United States
| | - Marco De Vivo
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
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32
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Devanand T, Krishnaswamy S, Vemparala S. Interdigitation of Lipids Induced by Membrane–Active Proteins. J Membr Biol 2019; 252:331-342. [DOI: 10.1007/s00232-019-00072-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/29/2019] [Indexed: 12/18/2022]
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33
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Petit JD, Immel F, Lins L, Bayer EM. Lipids or Proteins: Who Is Leading the Dance at Membrane Contact Sites? FRONTIERS IN PLANT SCIENCE 2019; 10:198. [PMID: 30846999 PMCID: PMC6393330 DOI: 10.3389/fpls.2019.00198] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 02/05/2019] [Indexed: 05/19/2023]
Abstract
Understanding the mode of action of membrane contact sites (MCSs) across eukaryotic organisms at the near-atomic level to infer function at the cellular and tissue levels is a challenge scientists are currently facing. These peculiar systems dedicated to inter-organellar communication are perfect examples of cellular processes where the interplay between lipids and proteins is critical. In this mini review, we underline the link between membrane lipid environment, the recruitment of proteins at specialized membrane domains and the function of MCSs. More precisely, we want to give insights on the crucial role of lipids in defining the specificity of plant endoplasmic reticulum (ER)-plasma membrane (PM) MCSs and we further propose approaches to study them at multiple scales. Our goal is not so much to go into detailed description of MCSs, as there are numerous focused reviews on the subject, but rather try to pinpoint the critical elements defining those structures and give an original point of view by considering the subject from a near-atomic angle with a focus on lipids. We review current knowledge as to how lipids can define MCS territories, play a role in the recruitment and function of the MCS-associated proteins and in turn, how the lipid environment can be modified by proteins.
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Affiliation(s)
- Jules D. Petit
- UMR5200 CNRS, Laboratory of Membrane Biogenesis, University of Bordeaux, Villenave d’Ornon, France
- Laboratoire de Biophysique Moléculaire aux Interfaces, TERRA Research Centre, GX ABT, Université de Liège, Liège, Belgium
| | - Françoise Immel
- UMR5200 CNRS, Laboratory of Membrane Biogenesis, University of Bordeaux, Villenave d’Ornon, France
| | - Laurence Lins
- Laboratoire de Biophysique Moléculaire aux Interfaces, TERRA Research Centre, GX ABT, Université de Liège, Liège, Belgium
| | - Emmanuelle M. Bayer
- UMR5200 CNRS, Laboratory of Membrane Biogenesis, University of Bordeaux, Villenave d’Ornon, France
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34
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Wildermuth KD, Monje-Galvan V, Warburton LM, Klauda JB. Effect of Membrane Lipid Packing on Stable Binding of the ALPS Peptide. J Chem Theory Comput 2019; 15:1418-1429. [DOI: 10.1021/acs.jctc.8b00945] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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35
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Qiao Q, Wei G, Yao D, Song Z. Formation of α-helical and β-sheet structures in membrane-bound human IAPP monomer and the resulting membrane deformation. Phys Chem Chem Phys 2019; 21:20239-20251. [DOI: 10.1039/c9cp03151k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Upon adsorption on membrane, human IAPP monomer takes conformational changes from coils to α-helices and β-sheets. The helices inserted and β on surface cause different types of membrane deformation, implying two distinct aggregation mechanisms.
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Affiliation(s)
- Qin Qiao
- Digital Medical Research Center
- School of Basic Medical Sciences
- Fudan University
- Shanghai 200032
- China
| | - Guanghong Wei
- Department of Physics
- State Key Laboratory of Surface Physics
- Key Laboratory for Computational Physical Science (Ministry of Education)
- Fudan University
- Shanghai 200438
| | - Demin Yao
- Digital Medical Research Center
- School of Basic Medical Sciences
- Fudan University
- Shanghai 200032
- China
| | - Zhijian Song
- Digital Medical Research Center
- School of Basic Medical Sciences
- Fudan University
- Shanghai 200032
- China
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36
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Briones R, Blau C, Kutzner C, de Groot BL, Aponte-Santamaría C. GROmaρs: A GROMACS-Based Toolset to Analyze Density Maps Derived from Molecular Dynamics Simulations. Biophys J 2018; 116:4-11. [PMID: 30558883 DOI: 10.1016/j.bpj.2018.11.3126] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/19/2018] [Accepted: 11/26/2018] [Indexed: 12/31/2022] Open
Abstract
We introduce a computational toolset, named GROmaρs, to obtain and compare time-averaged density maps from molecular dynamics simulations. GROmaρs efficiently computes density maps by fast multi-Gaussian spreading of atomic densities onto a three-dimensional grid. It complements existing map-based tools by enabling spatial inspection of atomic average localization during the simulations. Most importantly, it allows the comparison between computed and reference maps (e.g., experimental) through calculation of difference maps and local and time-resolved global correlation. These comparison operations proved useful to quantitatively contrast perturbed and control simulation data sets and to examine how much biomolecular systems resemble both synthetic and experimental density maps. This was especially advantageous for multimolecule systems in which standard comparisons like RMSDs are difficult to compute. In addition, GROmaρs incorporates absolute and relative spatial free-energy estimates to provide an energetic picture of atomistic localization. This is an open-source GROMACS-based toolset, thus allowing for static or dynamic selection of atoms or even coarse-grained beads for the density calculation. Furthermore, masking of regions was implemented to speed up calculations and to facilitate the comparison with experimental maps. Beyond map comparison, GROmaρs provides a straightforward method to detect solvent cavities and average charge distribution in biomolecular systems. We employed all these functionalities to inspect the localization of lipid and water molecules in aquaporin systems, the binding of cholesterol to the G protein coupled chemokine receptor type 4, and the identification of permeation pathways through the dermicidin antimicrobial channel. Based on these examples, we anticipate a high applicability of GROmaρs for the analysis of molecular dynamics simulations and their comparison with experimentally determined densities.
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Affiliation(s)
- Rodolfo Briones
- Computational Neurophysiology Group, Institute of Complex Systems 4, Forschungszentrum Jülich, Jülich, Germany
| | - Christian Blau
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholms Universitet, Stockholm, Sweden
| | - Carsten Kutzner
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Bert L de Groot
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Camilo Aponte-Santamaría
- Max Planck Tandem Group in Computational Biophysics, University of Los Andes, Bogotá, Colombia; Interdisciplinary Center for Scientific Computing, Heidelberg University, Heidelberg, Germany.
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