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Cordeiro MM, Filipe HAL, dos Santos P, Samelo J, Ramalho JPP, Loura LMS, Moreno MJ. Interaction of Hoechst 33342 with POPC Membranes at Different pH Values. Molecules 2023; 28:5640. [PMID: 37570608 PMCID: PMC10420284 DOI: 10.3390/molecules28155640] [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: 06/30/2023] [Revised: 07/18/2023] [Accepted: 07/21/2023] [Indexed: 08/13/2023] Open
Abstract
Hoechst 33342 (H33342) is a fluorescent probe that is commonly used to stain the DNA of living cells. To do so, it needs to interact with and permeate through cell membranes, despite its high overall charge at physiological pH values. In this work, we address the effect of pH in the association of H33342 with lipid bilayers using a combined experimental and computational approach. The partition of H33342 to 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid membranes was experimentally quantified using fluorescence spectroscopy and isothermal titration calorimetry (ITC) measurements. Quantum chemical calculations were performed to select the most stable isomer of H33342 for the overall charges 0, +1, and +2, expected to predominate across the 5 < pH < 10 range. The interaction of these isomers with POPC bilayers was then studied by both unrestrained and umbrella sampling molecular dynamics (MD) simulations. Both experimental results and computational free energy profiles indicate that the partition coefficient of H33342 displays a small variation over a wide pH range, not exceeding one order of magnitude. The enthalpy variation upon partition to the membrane suggests efficient hydrogen bonding between the probe and the lipid, namely, for the protonated +2 form, which was confirmed in the MD simulation studies. The relatively high lipophilicity obtained for the charged species contrasts with the decrease in their general hydrophobicity as estimated from octanol/water partition. This highlights the distinction between lipophilicity and hydrophobicity, as well as the importance of considering the association with lipid bilayers when predicting the affinity for biomembranes.
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Affiliation(s)
- Margarida M. Cordeiro
- Coimbra Chemistry Center, Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (M.M.C.); (H.A.L.F.); (J.S.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Hugo A. L. Filipe
- Coimbra Chemistry Center, Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (M.M.C.); (H.A.L.F.); (J.S.)
- Polytechnic of Guarda, CPIRN-IPG—Center of Potential and Innovation of Natural Resources, 6300-559 Guarda, Portugal
| | - Patrícia dos Santos
- Coimbra Chemistry Center, Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (M.M.C.); (H.A.L.F.); (J.S.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Jaime Samelo
- Coimbra Chemistry Center, Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (M.M.C.); (H.A.L.F.); (J.S.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - João P. Prates Ramalho
- LAQV, REQUIMTE, Hercules Laboratory, Department of Chemistry, School of Science and Technology, University of Évora, 7000-671 Évora, Portugal;
| | - Luís M. S. Loura
- Coimbra Chemistry Center, Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (M.M.C.); (H.A.L.F.); (J.S.)
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, 3004-535 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Maria J. Moreno
- Coimbra Chemistry Center, Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (M.M.C.); (H.A.L.F.); (J.S.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, 3004-535 Coimbra, Portugal
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Fluorescent Probes cis- and trans-Parinaric Acids in Fluid and Gel Lipid Bilayers: A Molecular Dynamics Study. Molecules 2023; 28:molecules28052241. [PMID: 36903487 PMCID: PMC10005308 DOI: 10.3390/molecules28052241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/20/2023] [Accepted: 02/23/2023] [Indexed: 03/04/2023] Open
Abstract
Fluorescence probes are indispensable tools in biochemical and biophysical membrane studies. Most of them possess extrinsic fluorophores, which often constitute a source of uncertainty and potential perturbation to the host system. In this regard, the few available intrinsically fluorescent membrane probes acquire increased importance. Among them, cis- and trans-parinaric acids (c-PnA and t-PnA, respectively) stand out as probes of membrane order and dynamics. These two compounds are long-chained fatty acids, differing solely in the configurations of two double bonds of their conjugated tetraene fluorophore. In this work, we employed all-atom and coarse-grained molecular dynamics simulations to study the behavior of c-PnA and t-PnA in lipid bilayers of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), representative of the liquid disordered and solid ordered lipid phases, respectively. All-atom simulations indicate that the two probes show similar location and orientation in the simulated systems, with the carboxylate facing the water/lipid interface and the tail spanning the membrane leaflet. The two probes establish interactions with the solvent and lipids to a similar degree in POPC. However, the almost linear t-PnA molecules have tighter lipid packing around them, especially in DPPC, where they also interact more with positively charged lipid choline groups. Probably for these reasons, while both probes show similar partition (assessed from computed free energy profiles across bilayers) to POPC, t-PnA clearly partitions more extensively than c-PnA to the gel phase. t-PnA also displays more hindered fluorophore rotation, especially in DPPC. Our results agree very well with experimental fluorescence data from the literature and allow deeper understanding of the behavior of these two reporters of membrane organization.
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Magalhães N, Simões GM, Ramos C, Samelo J, Oliveira AC, Filipe HAL, Ramalho JPP, Moreno MJ, Loura LMS. Interactions between Rhodamine Dyes and Model Membrane Systems—Insights from Molecular Dynamics Simulations. Molecules 2022; 27:molecules27041420. [PMID: 35209208 PMCID: PMC8876248 DOI: 10.3390/molecules27041420] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 02/04/2023] Open
Abstract
Background: rhodamines are dyes widely used as fluorescent tags in cell imaging, probing of mitochondrial membrane potential, and as P-glycoprotein model substrates. In all these applications, detailed understanding of the interaction between rhodamines and biomembranes is fundamental. Methods: we combined atomistic molecular dynamics (MD) simulations and fluorescence spectroscopy to characterize the interaction between rhodamines 123 and B (Rh123 and RhB, respectively) and POPC bilayers. Results: while the xanthene moiety orients roughly parallel to the membrane plane in unrestrained MD simulations, variations on the relative position of the benzoic ring (below the xanthene for Rh123, above it for RhB) were observed, and related to the structure of the two dyes and their interactions with water and lipids. Subtle distinctions were found among different ionization forms of the probes. Experimentally, RhB displayed a lipid/water partition coefficient more than two orders of magnitude higher than Rh123, in agreement with free energy profiles obtained from umbrella sampling MD. Conclusions: this work provided detailed insights on the similarities and differences in the behavior of bilayer-inserted Rh123 and RhB, related to the structure of the probes. The much higher affinity of RhB for the membranes increases the local concentration and explains its higher apparent affinity for P-glycoprotein reconstituted in model membranes.
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Affiliation(s)
- Nisa Magalhães
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Guilherme M. Simões
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Cristiana Ramos
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Jaime Samelo
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Alexandre C. Oliveira
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Hugo A. L. Filipe
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- CPIRN-IPG—Center of Potential and Innovation of Natural Resources, Polytechnic Institute of Guarda, 6300-559 Guarda, Portugal
| | - João P. Prates Ramalho
- Hercules Laboratory, LAQV, REQUIMTE, Department of Chemistry, School of Science and Technology, University of Évora, 7000-671 Evora, Portugal;
| | - Maria João Moreno
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
- CNC—Center for Neuroscience and Cell Biology, 3004-504 Coimbra, Portugal
| | - Luís M. S. Loura
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- CNC—Center for Neuroscience and Cell Biology, 3004-504 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
- Correspondence:
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Gracheva IA, Tretiakova DS, Zamyshlyaeva OG, Kudriashova ES, Vodovozova EL, Fedorov AY, Boldyrev IA. Cy5-Labeled Phosphatidylcholine. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2021. [DOI: 10.1134/s1068162021050265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Filipe HAL, Moreno MJ, Loura LMS. The Secret Lives of Fluorescent Membrane Probes as Revealed by Molecular Dynamics Simulations. Molecules 2020; 25:E3424. [PMID: 32731549 PMCID: PMC7435664 DOI: 10.3390/molecules25153424] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/23/2020] [Accepted: 07/25/2020] [Indexed: 12/15/2022] Open
Abstract
Fluorescent probes have been employed for more than half a century to study the structure and dynamics of model and biological membranes, using spectroscopic and/or microscopic experimental approaches. While their utilization has led to tremendous progress in our knowledge of membrane biophysics and physiology, in some respects the behavior of bilayer-inserted membrane probes has long remained inscrutable. The location, orientation and interaction of fluorophores with lipid and/or water molecules are often not well known, and they are crucial for understanding what the probe is actually reporting. Moreover, because the probe is an extraneous inclusion, it may perturb the properties of the host membrane system, altering the very properties it is supposed to measure. For these reasons, the need for independent methodologies to assess the behavior of bilayer-inserted fluorescence probes has been recognized for a long time. Because of recent improvements in computational tools, molecular dynamics (MD) simulations have become a popular means of obtaining this important information. The present review addresses MD studies of all major classes of fluorescent membrane probes, focusing in the period between 2011 and 2020, during which such work has undergone a dramatic surge in both the number of studies and the variety of probes and properties accessed.
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Affiliation(s)
- Hugo A. L. Filipe
- Chemistry Department, Coimbra Chemistry Center, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal;
| | - Maria João Moreno
- Coimbra Chemistry Center and CNC—Center for Neuroscience and Cell Biology, Chemistry Department, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal;
| | - Luís M. S. Loura
- Coimbra Chemistry Center and CNC—Center for Neuroscience and Cell Biology, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
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Prioli S, Reinholdt P, Hornum M, Kongsted J. Rational Design of Nile Red Analogs for Sensing in Membranes. J Phys Chem B 2019; 123:10424-10432. [PMID: 31730348 DOI: 10.1021/acs.jpcb.9b09691] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Development of next-generation fluorescent probes is a key element in the quest for a greater understanding of complex biological environments (e.g., membranes) by bioimaging. Such fluorescence-based techniques rely on specialized small molecules that possess excellent fluorescent properties but also do not perturb the native biological environment in which they reside. Herein we present a theoretical/computational strategy for the design of novel optical probes for sensing in membranes based on the parent chromophore Nile Red. Using a combination of time-dependent density functional theory (TD-DFT) and molecular dynamics (MD), we have studied the optical properties and accommodation in a model membrane of Nile Red and eight analogs. Special attention has been given to the design of probes with improved solvatochromism and two-photon absorption (2PA) without altering the membrane properties. Of the eight studied analogs, two probes were found to possess attractive probe features and are hence suggested to be taken forward to chemical synthesis and experimental exploration.
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Affiliation(s)
- Salvatore Prioli
- Department of Physics, Chemistry and Pharmacy , University of Southern Denmark , Campusvej 55 , DK-5230 Odense M , Denmark
| | - Peter Reinholdt
- Department of Physics, Chemistry and Pharmacy , University of Southern Denmark , Campusvej 55 , DK-5230 Odense M , Denmark
| | - Mick Hornum
- Department of Physics, Chemistry and Pharmacy , University of Southern Denmark , Campusvej 55 , DK-5230 Odense M , Denmark
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy , University of Southern Denmark , Campusvej 55 , DK-5230 Odense M , Denmark
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Enos N, Takenaka H, Scott S, Salfity HVN, Kirk M, Egar MW, Sarria DA, Slayback-Barry D, Belecky-Adams T, Chernoff EAG. Meningeal Foam Cells and Ependymal Cells in Axolotl Spinal Cord Regeneration. Front Immunol 2019; 10:2558. [PMID: 31736973 PMCID: PMC6838144 DOI: 10.3389/fimmu.2019.02558] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/15/2019] [Indexed: 12/01/2022] Open
Abstract
A previously unreported population of foam cells (foamy macrophages) accumulates in the invasive fibrotic meninges during gap regeneration of transected adult Axolotl spinal cord (salamander Ambystoma mexicanum) and may act beneficially. Multinucleated giant cells (MNGCs) also occurred in the fibrotic meninges. Actin-label localization and transmission electron microscopy showed characteristic foam cell and MNGC podosome and ruffled border-containing sealing ring structures involved in substratum attachment, with characteristic intermediate filament accumulations surrounding nuclei. These cells co-localized with regenerating cord ependymal cell (ependymoglial) outgrowth. Phase contrast-bright droplets labeled with Oil Red O, DiI, and DyRect polar lipid live cell label showed accumulated foamy macrophages to be heavily lipid-laden, while reactive ependymoglia contained smaller lipid droplets. Both cell types contained both neutral and polar lipids in lipid droplets. Foamy macrophages and ependymoglia expressed the lipid scavenger receptor CD36 (fatty acid translocase) and the co-transporter toll-like receptor-4 (TLR4). Competitive inhibitor treatment using the modified fatty acid Sulfo-N-succinimidyl Oleate verified the role of the lipid scavenger receptor CD36 in lipid uptake studies in vitro. Fluoromyelin staining showed both cell types took up myelin fragments in situ during the regeneration process. Foam cells took up DiI-Ox-LDL and DiI-myelin fragments in vitro while ependymoglia took up only DiI-myelin in vitro. Both cell types expressed the cysteine proteinase cathepsin K, with foam cells sequestering cathepsin K within the sealing ring adjacent to the culture substratum. The two cell types act as sinks for Ox-LDL and myelin fragments within the lesion site, with foamy macrophages showing more Ox-LDL uptake activity. Cathepsin K activity and cellular localization suggested that foamy macrophages digest ECM within reactive meninges, while ependymal cells act from within the spinal cord tissue during outgrowth into the lesion site, acting in complementary fashion. Small MNGCs also expressed lipid transporters and showed cathepsin K activity. Comparison of 3H-glucosamine uptake in ependymal cells and foam cells showed that only ependymal cells produce glycosaminoglycan and proteoglycan-containing ECM, while the cathepsin studies showed both cell types remove ECM. Interaction of foam cells and ependymoglia in vitro supported the dispersion of ependymal outgrowth associated with tissue reconstruction in Axolotl spinal cord regeneration.
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Affiliation(s)
- Nathaniel Enos
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Hidehito Takenaka
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Sarah Scott
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Hai V N Salfity
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Maia Kirk
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Margaret W Egar
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Deborah A Sarria
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Denise Slayback-Barry
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Teri Belecky-Adams
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Ellen A G Chernoff
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
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Temperature Dependence of the Structure and Dynamics of a Dye-Labeled Lipid in a Planar Phospholipid Bilayer: A Computational Study. J Membr Biol 2019; 252:227-240. [PMID: 31332471 DOI: 10.1007/s00232-019-00081-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 07/11/2019] [Indexed: 10/26/2022]
Abstract
Fluorescent probes are widely employed to label lipids for the investigation of structural and dynamic properties of model and cell membranes through optical microscopy techniques. Although the effect of tagging a lipid with an organic dye is generally assumed to be negligible, optically modified lipids can nonetheless affect the local lipid structure and, in turn, the lipid lateral mobility. To better assess this potential issue, all-atom (MD) molecular dynamics simulations have been performed to study structural and dynamic effects in a model DOPC membrane in the presence of a standard Rhodamine B-labeled DOPE lipid (RHB) as a function of temperature, i.e., 293 K, 303 K, and 320 K. As the temperature is increased, we observe similar changes in the structural properties of both pure DOPC and RHB-DOPC lipid bilayers: an increase of the area per lipid, a reduction of the membrane thickness and a decrease of lipid order parameters. The partial density profile of the RHB headgroups and their orientation within the lipid bilayer confirm the amphiphilic nature of the RHB fluorescent moiety, which mainly partitions in the DOPC glycerol backbone region at each temperature. Moreover, at all temperatures, our results on lipid lateral diffusion support a non-neutral role of the dye with respect to the unlabeled lipid mobility, thus suggesting important implications for optical microscopy studies of lipid membranes.
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The influence of 2-hydroxyoleic acid – an anticancer drug – on model membranes of different fluidity modulated by the cholesterol content. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.03.143] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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10
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Tretiakova D, Alekseeva A, Galimzyanov T, Boldyrev A, Chernyadyev A, Ermakov Y, Batishchev O, Vodovozova E, Boldyrev I. Lateral stress profile and fluorescent lipid probes. FRET pair of probes that introduces minimal distortions into lipid packing. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2337-2347. [DOI: 10.1016/j.bbamem.2018.05.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/17/2018] [Accepted: 05/30/2018] [Indexed: 12/31/2022]
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Location of fluorescent probes (2′-hydroxy derivatives of 2,5-diaryl-1,3-oxazole) in lipid membrane studied by fluorescence spectroscopy and molecular dynamics simulation. Biophys Chem 2018; 235:9-18. [DOI: 10.1016/j.bpc.2018.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 01/26/2018] [Accepted: 01/28/2018] [Indexed: 11/20/2022]
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12
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Xu W, Zeng Z, Jiang JH, Chang YT, Yuan L. Wahrnehmung der chemischen Prozesse in einzelnen Organellen mit niedermolekularen Fluoreszenzsonden. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201510721] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Wang Xu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 Volksrepublik China
- Department of Chemistry and Medicinal Chemistry Programme; National University of Singapore; Singapore 117543 Singapur
- Laboratory of Bioimaging Probe Development, A*STAR; Singapur
- Department of Chemistry; Stanford University; USA
| | - Zebing Zeng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 Volksrepublik China
| | - Jian-Hui Jiang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 Volksrepublik China
| | - Young-Tae Chang
- Department of Chemistry and Medicinal Chemistry Programme; National University of Singapore; Singapore 117543 Singapur
- Laboratory of Bioimaging Probe Development, A*STAR; Singapur
| | - Lin Yuan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 Volksrepublik China
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Xu W, Zeng Z, Jiang JH, Chang YT, Yuan L. Discerning the Chemistry in Individual Organelles with Small-Molecule Fluorescent Probes. Angew Chem Int Ed Engl 2016; 55:13658-13699. [DOI: 10.1002/anie.201510721] [Citation(s) in RCA: 526] [Impact Index Per Article: 65.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Indexed: 12/22/2022]
Affiliation(s)
- Wang Xu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P.R. China
- Department of Chemistry and Medicinal Chemistry Programme; National University of Singapore; Singapore 117543 Singapore
- Laboratory of Bioimaging Probe Development, A*STAR; Singapore
- Department of Chemistry; Stanford University; USA
| | - Zebing Zeng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P.R. China
| | - Jian-Hui Jiang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P.R. China
| | - Young-Tae Chang
- Department of Chemistry and Medicinal Chemistry Programme; National University of Singapore; Singapore 117543 Singapore
- Laboratory of Bioimaging Probe Development, A*STAR; Singapore
| | - Lin Yuan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P.R. China
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do Canto AMTM, Robalo JR, Santos PD, Carvalho AJP, Ramalho JPP, Loura LMS. Diphenylhexatriene membrane probes DPH and TMA-DPH: A comparative molecular dynamics simulation study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2647-2661. [PMID: 27475296 DOI: 10.1016/j.bbamem.2016.07.013] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 07/05/2016] [Accepted: 07/25/2016] [Indexed: 10/21/2022]
Abstract
Fluorescence spectroscopy and microscopy have been utilized as tools in membrane biophysics for decades now. Because phospholipids are non-fluorescent, the use of extrinsic membrane probes in this context is commonplace. Among the latter, 1,6-diphenylhexatriene (DPH) and its trimethylammonium derivative (TMA-DPH) have been extensively used. It is widely believed that, owing to its additional charged group, TMA-DPH is anchored at the lipid/water interface and reports on a bilayer region that is distinct from that of the hydrophobic DPH. In this study, we employ atomistic MD simulations to characterize the behavior of DPH and TMA-DPH in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and POPC/cholesterol (4:1) bilayers. We show that although the dynamics of TMA-DPH in these membranes is noticeably more hindered than that of DPH, the location of the average fluorophore of TMA-DPH is only ~3-4Å more shallow than that of DPH. The hindrance observed in the translational and rotational motions of TMA-DPH compared to DPH is mainly not due to significant differences in depth, but to the favorable electrostatic interactions of the former with electronegative lipid atoms instead. By revealing detailed insights on the behavior of these two probes, our results are useful both in the interpretation of past work and in the planning of future experiments using them as membrane reporters.
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Affiliation(s)
- António M T M do Canto
- Centro de Química de Évora e Departamento de Química, Escola de Ciências e Tecnologia, Colégio Luís Verney, Rua Romão Ramalho 59, P-7002-554 Évora, Portugal
| | - João R Robalo
- Centro de Química de Évora e Departamento de Química, Escola de Ciências e Tecnologia, Colégio Luís Verney, Rua Romão Ramalho 59, P-7002-554 Évora, Portugal; Theory and Bio-Systems Department, Max Planck Institute of Colloids and Interfaces, Wissenschaftspark Golm, D-14424 Potsdam, Germany
| | - Patrícia D Santos
- Centro de Química de Évora e Departamento de Química, Escola de Ciências e Tecnologia, Colégio Luís Verney, Rua Romão Ramalho 59, P-7002-554 Évora, Portugal
| | - Alfredo J Palace Carvalho
- Centro de Química de Évora e Departamento de Química, Escola de Ciências e Tecnologia, Colégio Luís Verney, Rua Romão Ramalho 59, P-7002-554 Évora, Portugal
| | - J P Prates Ramalho
- Centro de Química de Évora e Departamento de Química, Escola de Ciências e Tecnologia, Colégio Luís Verney, Rua Romão Ramalho 59, P-7002-554 Évora, Portugal
| | - Luís M S Loura
- Faculdade de Farmácia, Universidade de Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, P-3000-548 Coimbra, Portugal; Centro de Química de Coimbra, Largo D. Dinis, Rua Larga, P-3004-535 Coimbra, Portugal.
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15
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do Canto AM, Santos PD, Martins J, Loura LM. Behavior of pyrene as a polarity probe in palmitoylsphingomyelin and palmitoylsphingomyelin/cholesterol bilayers: A molecular dynamics simulation study. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2014.12.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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16
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Godin R, Liu HW, Smith L, Cosa G. Dye lipophilicity and retention in lipid membranes: implications for single-molecule spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:11138-11146. [PMID: 25158129 DOI: 10.1021/la5021669] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Fluorescence studies of individual lipid vesicles rely on the proper positioning of probes in the lipid milieu. This is true for both positional tags and chemoselective fluorogenic probes that undergo chemical modification following reaction with an analyte of interest within the lipid environment. The present report describes lipophilicity and localization estimations for a series of BODIPY dyes bearing substituents of varying hydrophobicity. We also studied fluorogenic trap-reporter probes that undergo fluorescence emission enhancement upon trapping of reactive oxygen species (ROS), including lipid peroxyl radicals. We show that caution has to be taken to extrapolate ensemble partition measurements of dyes to the single-molecule regime as a result of the dramatically different lipid concentration prevailing in ensemble versus single-molecule experiments. We show that the mole fraction of dyes that remains embedded in liposomes during a typical single-molecule experiment may be accurately determined from a ratiometric single-particle imaging analysis. We further demonstrate that fluorescence correlation spectroscopy (FCS) provides a very rapid and reliable estimate of the lipophilic nature of a given dye under highly dilute single-molecule-like conditions. Our combined single-particle spectroscopy and FCS experiments suggest that the minimal mole fraction of membrane-associated dyes (x(m)) as determined from FCS experiments is about 0.5 for adequate dye retention during single-molecule imaging in lipid membranes. Our work further highlights the dramatic effect that chemical modifications can have on chemoselective fluorogenic probe localization.
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Affiliation(s)
- Robert Godin
- Department of Chemistry and Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), McGill University , 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
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Robalo JR, Ramalho JPP, Loura LMS. NBD-Labeled Cholesterol Analogues in Phospholipid Bilayers: Insights from Molecular Dynamics. J Phys Chem B 2013; 117:13731-42. [DOI: 10.1021/jp406135a] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- João R. Robalo
- Departamento
de Química, Escola de Ciências e Tecnologia, Universidade de Évora, Rua Romão Ramalho, 59, 7000-671 Évora, Portugal
- Centro
de Química de Évora, Universidade de Évora, Rua
Romão Ramalho, 59, 7000-671 Évora, Portugal
| | - J. P. Prates Ramalho
- Departamento
de Química, Escola de Ciências e Tecnologia, Universidade de Évora, Rua Romão Ramalho, 59, 7000-671 Évora, Portugal
- Centro
de Química de Évora, Universidade de Évora, Rua
Romão Ramalho, 59, 7000-671 Évora, Portugal
| | - Luís M. S. Loura
- Faculdade
de Farmácia, Universidade de Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
- Centro
de Química de Coimbra, Largo D. Dinis, Rua Larga, 3004-535 Coimbra, Portugal
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18
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Robalo JR, do Canto AMTM, Carvalho AJP, Ramalho JPP, Loura LMS. Behavior of Fluorescent Cholesterol Analogues Dehydroergosterol and Cholestatrienol in Lipid Bilayers: A Molecular Dynamics Study. J Phys Chem B 2013; 117:5806-19. [DOI: 10.1021/jp312026u] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | - Luís M. S. Loura
- Faculdade de Farmácia, Universidade de Coimbra, Pólo das Ciências
da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
- Centro de Química de Coimbra, Largo D. Dinis, Rua Larga, 3004-535 Coimbra,
Portugal
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19
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Ackerman DG, Heberle FA, Feigenson GW. Limited perturbation of a DPPC bilayer by fluorescent lipid probes: a molecular dynamics study. J Phys Chem B 2013; 117:4844-52. [PMID: 23548205 DOI: 10.1021/jp400289d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The properties of lipid bilayer nanometer-scale domains could be crucial for understanding cell membranes. Fluorescent probes are often used to study bilayers, yet their effects on host lipids are not well understood. We used molecular dynamics simulations to investigate perturbations in a fluid DPPC bilayer upon incorporation of three indocarbocyanine probes: DiI-C18:0, DiI-C18:2, or DiI-C12:0. We find a 10-12% decrease in chain order for DPPC in the solvation shell nearest the probe but smaller effects in subsequent shells, indicating that the probes significantly alter only their local environment. We also observe order perturbations of lipids directly across from the probe in the opposite leaflet. Additionally, the DPPC headgroup phosphorus-to-nitrogen vector of lipids nearest the probe exhibits preferential orientation pointing away from the DiI. We show that, while DiI probes perturb their local environment, they do not strongly influence the average properties of "nanoscopic" domains containing a few hundred lipids.
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Affiliation(s)
- David G Ackerman
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, United States
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Sensing hydration and behavior of pyrene in POPC and POPC/cholesterol bilayers: A molecular dynamics study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1094-101. [DOI: 10.1016/j.bbamem.2012.12.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Revised: 12/12/2012] [Accepted: 12/18/2012] [Indexed: 01/24/2023]
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21
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Simple estimation of Förster Resonance Energy Transfer (FRET) orientation factor distribution in membranes. Int J Mol Sci 2012. [PMID: 23203123 PMCID: PMC3509639 DOI: 10.3390/ijms131115252] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Because of its acute sensitivity to distance in the nanometer scale, Förster resonance energy transfer (FRET) has found a large variety of applications in many fields of chemistry, physics, and biology. One important issue regarding the correct usage of FRET is its dependence on the donor-acceptor relative orientation, expressed as the orientation factor κ2. Different donor/acceptor conformations can lead to κ2 values in the 0 ≤ κ2 ≤ 4 range. Because the characteristic distance for FRET, R0, is proportional to (κ2)1/6, uncertainties in the orientation factor are reflected in the quality of information that can be retrieved from a FRET experiment. In most cases, the average value of κ2 corresponding to the dynamic isotropic limit (<κ2> = 2/3) is used for computation of R0 and hence donor-acceptor distances and acceptor concentrations. However, this can lead to significant error in unfavorable cases. This issue is more critical in membrane systems, because of their intrinsically anisotropic nature and their reduced fluidity in comparison to most common solvents. Here, a simple numerical simulation method for estimation of the probability density function of κ2 for membrane-embedded donor and acceptor fluorophores in the dynamic regime is presented. In the simplest form, the proposed procedure uses as input the most probable orientations of the donor and acceptor transition dipoles, obtained by experimental (including linear dichroism) or theoretical (such as molecular dynamics simulation) techniques. Optionally, information about the widths of the donor and/or acceptor angular distributions may be incorporated. The methodology is illustrated for special limiting cases and common membrane FRET pairs.
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22
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Loura LMS. Lateral distribution of NBD-PC fluorescent lipid analogs in membranes probed by molecular dynamics-assisted analysis of Förster Resonance Energy Transfer (FRET) and fluorescence quenching. Int J Mol Sci 2012; 13:14545-64. [PMID: 23203080 PMCID: PMC3509596 DOI: 10.3390/ijms131114545] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 10/29/2012] [Accepted: 11/01/2012] [Indexed: 01/19/2023] Open
Abstract
Förster resonance energy transfer (FRET) is a powerful tool used for many problems in membrane biophysics, including characterization of the lateral distribution of lipid components and other species of interest. However, quantitative analysis of FRET data with a topological model requires adequate choices for the values of several input parameters, some of which are difficult to obtain experimentally in an independent manner. For this purpose, atomistic molecular dynamics (MD) simulations can be potentially useful as they provide direct detailed information on transverse probe localization, relative probe orientation, and membrane surface area, all of which are required for analysis of FRET data. This is illustrated here for the FRET pairs involving 1,6-diphenylhexatriene (DPH) as donor and either 1-palmitoyl,2-(6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino] hexanoyl)- sn-glycero-3-phosphocholine (C6-NBD-PC) or 1-palmitoyl,2-(12-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]dodecanoyl)-sn-glycero-3-phosphocholine (C12-NBD-PC) as acceptors, in fluid vesicles of 1,2-dipalmitoyl-sn-3-glycerophosphocholine (DPPC, 50 °C). Incorporation of results from MD simulations improves the statistical quality of model fitting to the experimental FRET data. Furthermore, the decay of DPH in the presence of moderate amounts of C12-NBD-PC (>0.4 mol%) is consistent with non-random lateral distribution of the latter, at variance with C6-NBD-PC, for which aggregation is ruled out up to 2.5 mol% concentration. These conclusions are supported by analysis of NBD-PC fluorescence self-quenching. Implications regarding the relative utility of these probes in membrane studies are discussed.
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Affiliation(s)
- Luís M S Loura
- Faculty of Pharmacy, University of Coimbra, Health Sciences Campus, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
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23
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Nitschke WK, Vequi-Suplicy CC, Coutinho K, Stassen H. Molecular Dynamics Investigations of PRODAN in a DLPC Bilayer. J Phys Chem B 2012; 116:2713-21. [DOI: 10.1021/jp2085582] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- William K. Nitschke
- Grupo de Química Teórica, Instituto de Química, UFRGS Av. Bento Gonçalves
9500, 91540-000 Porto Alegre, Brazil
| | | | - Kaline Coutinho
- Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970
São Paulo, Brazil
| | - Hubert Stassen
- Grupo de Química Teórica, Instituto de Química, UFRGS Av. Bento Gonçalves
9500, 91540-000 Porto Alegre, Brazil
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Loura LMS, Ramalho JPP. Recent developments in molecular dynamics simulations of fluorescent membrane probes. Molecules 2011; 16:5437-52. [PMID: 21709624 PMCID: PMC6264736 DOI: 10.3390/molecules16075437] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 06/21/2011] [Accepted: 06/22/2011] [Indexed: 01/25/2023] Open
Abstract
Due to their sensitivity and versatility, the use of fluorescence techniques in membrane biophysics is widespread. Because membrane lipids are non-fluorescent, extrinsic membrane probes are widely used. However, the behaviour of these probes when inserted in the bilayer is often poorly understood, and it can be hard to distinguish between legitimate membrane properties and perturbation resulting from probe incorporation. Atomistic molecular dynamics simulations present a convenient way to address these issues and have been increasingly used in recent years in this context. This article reviews the application of molecular dynamics to the study of fluorescent membrane probes, focusing on recent work with complex design fluorophores and ordered bilayer systems.
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Affiliation(s)
- Luís M. S. Loura
- Faculdade de Farmácia, Universidade de Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal;
- Centro de Química de Coimbra, Universidade de Coimbra, Rua Larga, 3004-535 Coimbra, Portugal
| | - J. P. Prates Ramalho
- Centro de Química de Évora e Departamento de Química, Escola de Ciências e Tecnologia, Colégio Luís Verney, Rua Romão Ramalho 59, 7002-554 Évora, Portugal
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25
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Direct calculation of Förster orientation factor of membrane probes by molecular simulation. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.theochem.2010.01.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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