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Moqadam M, Gartan P, Talandashti R, Chiapparino A, Titeca K, Gavin AC, Reuter N. A Membrane-Assisted Mechanism for the Release of Ceramide from the CERT START Domain. J Phys Chem B 2024; 128:6338-6351. [PMID: 38903016 PMCID: PMC11228987 DOI: 10.1021/acs.jpcb.4c02398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/26/2024] [Accepted: 06/11/2024] [Indexed: 06/22/2024]
Abstract
Ceramide transfer protein CERT is the mediator of nonvesicular transfer of ceramide from the ER to Golgi. In CERT, START is the domain responsible for the binding and transport of ceramide. A wealth of structural data has revealed a helix-grip fold surrounding a large hydrophobic cavity holding the ceramide. Yet, little is known about the mechanisms by which START releases the ceramide through the polar region and into the packed environment of cellular membranes. As such events do not lend themselves easily to experimental investigations, we used multiple unbiased microsecond-long molecular simulations. We propose a membrane-assisted mechanism in which the membrane acts as an allosteric effector initiating the release of ceramide and where the passage of the ceramide acyl chains is facilitated by the intercalation of a single phosphatidylcholine lipid in the cavity, practically greasing the ceramide way out. We verify using free energy calculation and experimental lipidomics data that CERT forms stable complexes with phosphatidylcholine lipids, in addition to ceramide, thus providing validation for the proposed mechanism.
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Affiliation(s)
- Mahmoud Moqadam
- Department
of Chemistry, University of Bergen, Bergen 5020, Norway
- Computational
Biology Unit, Department of Informatics, University of Bergen, Bergen 5020, Norway
| | - Parveen Gartan
- Department
of Chemistry, University of Bergen, Bergen 5020, Norway
- Computational
Biology Unit, Department of Informatics, University of Bergen, Bergen 5020, Norway
| | - Reza Talandashti
- Department
of Chemistry, University of Bergen, Bergen 5020, Norway
- Computational
Biology Unit, Department of Informatics, University of Bergen, Bergen 5020, Norway
| | - Antonella Chiapparino
- European
Molecular Biology Laboratory, EMBL, Meyerhofstrasse 1, Heidelberg D-69117, Germany
| | - Kevin Titeca
- European
Molecular Biology Laboratory, EMBL, Meyerhofstrasse 1, Heidelberg D-69117, Germany
- Department
of Cell Physiology and Metabolism, University
of Geneva, CMU Rue Michel-Servet 1, Genève 4 1211, Switzerland
| | - Anne-Claude Gavin
- Department
of Cell Physiology and Metabolism, University
of Geneva, CMU Rue Michel-Servet 1, Genève 4 1211, Switzerland
| | - Nathalie Reuter
- Department
of Chemistry, University of Bergen, Bergen 5020, Norway
- Computational
Biology Unit, Department of Informatics, University of Bergen, Bergen 5020, Norway
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2
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Xie J, Pink DL, Jayne Lawrence M, Lorenz CD. Digestion of lipid micelles leads to increased membrane permeability. NANOSCALE 2024; 16:2642-2653. [PMID: 38229565 DOI: 10.1039/d3nr05083a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Lipid-based drug carriers are an attractive option to solubilise poorly water soluble therapeutics. Previously, we reported that the digestion of a short tail PC lipid (2C6PC) by the PLA2 enzyme has a significant effect on the structure and stability of the micelles it forms. Here, we studied the interactions of micelles of varying composition representing various degrees of digestion with a model ordered (70 mol% DPPC & 30 mol% cholesterol) and disordered (100% DOPC) lipid membrane. Micelles of all compositions disassociated when interacting with the two different membranes. As the percentage of digestion products (C6FA and C6LYSO) in the micelle increased, the disassociation occurred more rapidly. The C6FA inserts preferentially into both membranes. We find that all micelle components increase the area per lipid, increase the disorder and decrease the thickness of the membranes, and the 2C6PC lipid molecules have the most significant impact. Additionally, there is an increase in permeation of water into the membrane that accompanies the insertion of C6FA into the DOPC membranes. We show that the natural digestion of lipid micelles result in molecular species that can enhance the permeability of lipid membranes that in turn result in an enhanced delivery of drugs.
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Affiliation(s)
- Jun Xie
- Biological & Soft Matter Research Group, Department of Physics, Faculty of Natural, Mathematical & Engineering Sciences, King's College London, London, UK.
| | - Demi L Pink
- Biological & Soft Matter Research Group, Department of Physics, Faculty of Natural, Mathematical & Engineering Sciences, King's College London, London, UK.
| | - M Jayne Lawrence
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Stopford Building, Oxford Road, Manchester, UK
| | - Christian D Lorenz
- Biological & Soft Matter Research Group, Department of Physics, Faculty of Natural, Mathematical & Engineering Sciences, King's College London, London, UK.
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3
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Sariyer E, Sariyer AS. Computational prediction of analog compounds of the membrane protein MCHR1 antagonists ALB-127158 and KRX-104130. J Bioenerg Biomembr 2023; 55:435-446. [PMID: 37940722 DOI: 10.1007/s10863-023-09993-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 10/28/2023] [Indexed: 11/10/2023]
Abstract
Obesity, which is already pervasive throughout the world, endangers public health by raising the prevalence of metabolic disorders and making their treatment more difficult. The development of drugs to treat obesity is a focus of effort. Melanin concentrated hormone receptor 1 (MCHR1) is the target of some of these therapeutic possibilities since as increased levels of melanin concentrated hormone have been found in obesity models. Known MCHR1 antagonists include BMS-830216, GW-856464, NGD-4715, ALB-127158, and AMG 076, but many have failed phase-I clinical studies. As a potential treatment for cardiotoxicity, KRX-104130 has only recently been identified. As MCH system is potentially effective target for treatment of obesity, in silico research into interaction between MCHR1 and its antagonists at molecular level was the primary goal of this study. Analogues ALB-127158 and KRX-104130 were screened among the RealEnamine library. The complexes obtained by molecular docking were embedded in mimics brain-cell membrane and simulated for 540 ns, and then MM-GBSA were calculated with MMPBSA.py. With all these computational studies, similar or different aspects of selected analogous compounds to ALB-127158 and KRX-104130 were investigated. The specificity of this study was that it analyzed MCHR1 protein as embedded in membrane. It was concluded that KRX-104130's analogue Z1922310273 and ALB-127158's analogue PV-002757495233 did not cause a difference in terms of phospholipid membrane properties. In addition, all ligands remained stable in putative binding site. It has been suggested that PV-002757495233 and Z1922310273 compounds can be evaluated as MCHR1 antagonists when all these outputs are considered in melting pots.
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Affiliation(s)
- Emrah Sariyer
- Vocational School of Health Services, Medical Laboratory Techniques, Artvin Coruh University, Artvin, Turkey.
| | - Ayşegül Saral Sariyer
- Faculty of Health Sciences, Department of Nutrition and Dietetics, Artvin Coruh University, Artvin, Turkey
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4
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Jorgensen C, Troendle EP, Ulmschneider JP, Searson PC, Ulmschneider MB. A least-squares-fitting procedure for an efficient preclinical ranking of passive transport across the blood-brain barrier endothelium. J Comput Aided Mol Des 2023; 37:537-549. [PMID: 37573260 PMCID: PMC10505096 DOI: 10.1007/s10822-023-00525-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 07/24/2023] [Indexed: 08/14/2023]
Abstract
The treatment of various disorders of the central nervous system (CNS) is often impeded by the limited brain exposure of drugs, which is regulated by the human blood-brain barrier (BBB). The screening of lead compounds for CNS penetration is challenging due to the biochemical complexity of the BBB, while experimental determination of permeability is not feasible for all types of compounds. Here we present a novel method for rapid preclinical screening of libraries of compounds by utilizing advancements in computing hardware, with its foundation in transition-based counting of the flux. This method has been experimentally validated for in vitro permeabilities and provides atomic-level insights into transport mechanisms. Our approach only requires a single high-temperature simulation to rank a compound relative to a library, with a typical simulation time converging within 24 to 72 h. The method offers unbiased thermodynamic and kinetic information to interpret the passive transport of small-molecule drugs across the BBB.
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Affiliation(s)
- Christian Jorgensen
- Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD, USA.
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark.
| | | | | | - Peter C Searson
- Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD, USA
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
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5
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Castro DC, Smith KW, Norsworthy MD, Rubakhin SS, Weisbrod CR, Hendrickson CL, Sweedler JV. Single-Cell and Subcellular Analysis Using Ultrahigh Resolution 21 T MALDI FTICR Mass Spectrometry. Anal Chem 2023; 95:6980-6988. [PMID: 37070980 PMCID: PMC10190686 DOI: 10.1021/acs.analchem.3c00393] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
The mammalian brain contains ∼20,000 distinct lipid species that contribute to its structural organization and function. The lipid profiles of cells change in response to a variety of cellular signals and environmental conditions that result in modulation of cell function through alteration of phenotype. The limited sample material combined with the vast chemical diversity of lipids makes comprehensive lipid profiling of individual cells challenging. Here, we leverage the resolving power of a 21 T Fourier-transform ion cyclotron resonance (FTICR) mass spectrometer for chemical characterization of individual hippocampal cells at ultrahigh mass resolution. The accuracy of the acquired data allowed differentiation of freshly isolated and cultured hippocampal cell populations, as well as finding differences in lipids between the soma and neuronal processes of the same cell. Differences in lipids include TG 42:2 observed solely in the cell bodies and SM 34:1;O2 found only in the cellular processes. The work represents the first mammalian single cells analyzed at ultrahigh resolution and is an advance in the performance of mass spectrometry (MS) for single-cell research.
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Affiliation(s)
- Daniel C. Castro
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana, IL 61801, United States
| | - Karl W. Smith
- National High Magnetic Field Laboratory, Florida State University, 1801 East Paul Dirac Drive, Tallahassee, FL 32310, United States
| | - Miles D. Norsworthy
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana, IL 61801, United States
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801 United States
| | - Stanislav S. Rubakhin
- Department of Chemistry, University of Illinois at Urbana-Champaign, 505 South Mathews Avenue, Urbana IL 61801, United States
- Neuroscience Program, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana, IL 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana, IL 61801, United States
| | - Chad R. Weisbrod
- National High Magnetic Field Laboratory, Florida State University, 1801 East Paul Dirac Drive, Tallahassee, FL 32310, United States
| | - Christopher L. Hendrickson
- National High Magnetic Field Laboratory, Florida State University, 1801 East Paul Dirac Drive, Tallahassee, FL 32310, United States
| | - Jonathan V. Sweedler
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign, 505 South Mathews Avenue, Urbana IL 61801, United States
- Neuroscience Program, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana, IL 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana, IL 61801, United States
- Department of Bioengineering, University of Illinois at Urbana-Champaign, 1406 West Green Street, Urbana, IL 61801, United States
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6
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Heinonen S, Lautala S, Koivuniemi A, Bunker A. Insights into the behavior of unsaturated diacylglycerols in mixed lipid bilayers in relation to protein kinase C activation-A molecular dynamics simulation study. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183961. [PMID: 35568204 DOI: 10.1016/j.bbamem.2022.183961] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 06/15/2023]
Abstract
The lipid second messenger diacylglycerol (DAG) is known for its involvement in many types of cellular signaling, especially as an endogenous agonist for protein kinase C (PKC). Evidence has emerged that the degree of saturation of the DAG molecules can affect PKC activation. DAG molecules with different acyl chain saturation have not only been observed to induce varying extents of PKC activation, but also to express selectivity towards different PKC isozymes. Both qualities are important for precise therapeutic activation of PKC; understanding DAG behavior at the molecular level in different environments has much potential in the development of drugs to target PKC. We used molecular dynamics simulations to study the behavior of two different unsaturated DAG species in lipid environments with varying degrees of unsaturation. We focus on phosphatidylethanolamine (PE) instead of phosphatidylcholine (PC) to more accurately model the relevant biomembranes. The effect of cholesterol (CHOL) on these systems was also explored. We found that both high level of unsaturation in the acyl chains of the DAG species and presence of CHOL in the surrounding membrane increase DAG molecule availability at the lipid-water interface. This can partially explain the previously observed differences in PKC activation strength and specificity, the complete mechanism is, however, likely to be more complex. Our simulations coupled with the current understanding of lipids highlight the need for more simulations of biologically accurate lipid environments in order to determine the correct correlations between molecular mechanisms and biological behavior when studying PKC activation.
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Affiliation(s)
- Suvi Heinonen
- Drug Research Program, Division of Pharmaceutical Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
| | - Saara Lautala
- Drug Research Program, Division of Pharmaceutical Biosciences, University of Helsinki, FI-00014, Helsinki, Finland.
| | - Artturi Koivuniemi
- Drug Research Program, Division of Pharmaceutical Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
| | - Alex Bunker
- Drug Research Program, Division of Pharmaceutical Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
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7
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Joodaki F, Martin LM, Greenfield ML. Generation and Computational Characterization of a Complex Staphylococcus aureus Lipid Bilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:9481-9499. [PMID: 35901279 DOI: 10.1021/acs.langmuir.2c00483] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Studies indicate a crucial cell membrane role in the antibiotic resistance of Staphylococcus aureus. To simulate its membrane structure and dynamics, a complex molecular-scale computational representation of the S. aureus lipid bilayer was developed. Phospholipid types and their amounts were optimized by reverse Monte Carlo to represent characterization data from the literature, leading to 19 different phospholipid types that combine three headgroups [phosphatidylglycerol, lysyl-phosphatidylglycerol (LPG), and cardiolipin] and 10 tails, including iso- and anteiso-branched saturated chains. The averaged lipid bilayer thickness was 36.7 Å, and area per headgroup was 67.8 Å2. Phosphorus and nitrogen density profiles showed that LPG headgroups tended to be bent and oriented more parallel to the bilayer plane. The water density profile showed that small amounts reached the membrane center. Carbon density profiles indicated hydrophobic interactions for all lipids in the middle of the bilayer. Bond vector order parameters along each tail demonstrated different C-H ordering even within distinct lipids of the same type; however, all tails followed similar trends in average order parameter. These complex simulations further revealed bilayer insights beyond those attainable with monodisperse, unbranched lipids. Longer tails often extended into the opposite leaflet. Carbon at and beyond a branch showed significantly decreased ordering compared to carbon in unbranched tails; this feature arose in every branched lipid. Diverse tail lengths distributed these disordered methyl groups throughout the middle third of the bilayer. Distributions in mobility and ordering reveal diverse properties that cannot be obtained with monodisperse lipids.
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Affiliation(s)
- Faramarz Joodaki
- Department of Chemical Engineering, University of Rhode Island, 360 Fascitelli Center for Advanced Engineering, Kingston, Rhode Island 02881, United States
| | - Lenore M Martin
- Department of Cell and Molecular Biology, University of Rhode Island, 120 Flagg Road, Kingston, Rhode Island 02881, United States
| | - Michael L Greenfield
- Department of Chemical Engineering, University of Rhode Island, 360 Fascitelli Center for Advanced Engineering, Kingston, Rhode Island 02881, United States
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8
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Sarkar P, Chattopadhyay A. Membrane Dipole Potential: An Emerging Approach to Explore Membrane Organization and Function. J Phys Chem B 2022; 126:4415-4430. [PMID: 35696090 DOI: 10.1021/acs.jpcb.2c02476] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biological membranes are complex organized molecular assemblies of lipids and proteins that provide cells and membrane-bound intracellular organelles their individual identities by morphological compartmentalization. Membrane dipole potential originates from the electrostatic potential difference within the membrane due to the nonrandom arrangement (orientation) of amphiphile and solvent (water) dipoles at the membrane interface. In this Feature Article, we will focus on the measurement of dipole potential using electrochromic fluorescent probes and highlight interesting applications. In addition, we will focus on ratiometric fluorescence microscopic imaging technique to measure dipole potential in cellular membranes, a technique that can be used to address novel problems in cell biology which are otherwise difficult to address using available approaches. We envision that membrane dipole potential could turn out to be a convenient tool in exploring the complex interplay between membrane lipids and proteins and could provide novel insights in membrane organization and function.
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Affiliation(s)
- Parijat Sarkar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
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9
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Smith P, Lorenz CD. LiPyphilic: A Python Toolkit for the Analysis of Lipid Membrane Simulations. J Chem Theory Comput 2021; 17:5907-5919. [PMID: 34450002 DOI: 10.1021/acs.jctc.1c00447] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular dynamics simulations are now widely used to study emergent phenomena in lipid membranes with complex compositions. Here, we present LiPyphilic-a fast, fully tested, and easy-to-install Python package for analyzing such simulations. Analysis tools in LiPyphilic include the identification of cholesterol flip-flop events, the classification of local lipid environments, and the degree of interleaflet registration. LiPyphilic is both force field- and resolution-agnostic, and by using the powerful atom selection language of MDAnalysis, it can handle membranes with highly complex compositions. LiPyphilic also offers two on-the-fly trajectory transformations to (i) fix membranes split across periodic boundaries and (ii) perform nojump coordinate unwrapping. Our implementation of nojump unwrapping accounts for fluctuations in the box volume under the NPT ensemble-an issue that most current implementations have overlooked. The full documentation of LiPyphilic, including installation instructions and links to interactive online tutorials, is available at https://lipyphilic.readthedocs.io/en/latest.
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Affiliation(s)
- Paul Smith
- Department of Physics, King's College London, London WC2R 2LS, U.K
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10
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Yee SM, Lorenz CD. On the Structure and Flip-flop of Free Docosahexaenoic Acid in a Model Human Brain Membrane. J Phys Chem B 2021; 125:8038-8047. [PMID: 34270235 DOI: 10.1021/acs.jpcb.1c03929] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Among the omega-3 fatty acids, docosahexaenoic acid (DHA, sn22:6) is particularly vital in human brain cell membranes. There is considerable interest in DHA because low-level DHA has been associated with declined cognitive function and poor visual acuity. In this work, atomistic molecular dynamics simulations were used to investigate the effects of free protonated DHA (DHAP) in molar fractions of 0, 17, 30, and 38% in a realistic model of a healthy brain cell membrane comprising 26 lipid types. Numerous flip-flop events of DHAP were observed and categorized as successful or aborted. Novel use of the machine learning technique, density-based spatial clustering of applications with noise (DBSCAN), effectively identified flip-flop events by way of clustering. Our data show that increasing amounts of DHAP in the membrane disorder the bilayer packing, fluidize the membrane, and increase the rates of successful flip-flop from k = 0.2 μs-1 (17% DHAP) to 0.8 μs-1 (30% DHAP) and to 1.3 μs-1 (38% DHAP). In addition, we also provided a detailed understanding of the flip-flop mechanism of DHAP across this complex membrane. Interestingly, we noted the role of hydrogen bonds in two distinct coordinated flip-flop phenomena between two DHAP molecules: double flip-flop and assisted flip-flop. Understanding the effects of various concentrations of DHAP on the dynamics within a lipid membrane and the resulting structural properties of the membrane are important when considering the use of DHAP as a dietary supplement or as a potential therapeutic.
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Affiliation(s)
- Sze May Yee
- Department of Physics, King's College London, London WC2R 2LS, United Kingdom
| | - Christian D Lorenz
- Department of Physics, King's College London, London WC2R 2LS, United Kingdom
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