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Duncan KM, Trousdale RC, Gonzales CN, Steel WH, Walker RA. l-Phenylalanine Partitioning Mechanisms in Model Biological Membranes. J Phys Chem B 2023. [PMID: 37315336 DOI: 10.1021/acs.jpcb.2c08582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Time-resolved fluorescence spectroscopy in combination with differential scanning calorimetry (DSC) was used to study the chemical interactions that occur when l-phenylalanine is introduced to solutions containing phosphatidylcholine vesicles. Studies reported in this work address open questions about l-Phe's affinity for lipid vesicle bilayers, the effects of l-Phe partitioning on bilayer properties, l-Phe's solvation within a lipid bilayer, and the amount of l-Phe within that local solvation environment. DSC data show that l-Phe reduces the amount of heat necessary to melt saturated phosphatidylcholine bilayers from their gel to liquid-crystalline state but does not change the transition temperature (Tgel-lc). Time-resolved emission shows only a single l-Phe lifetime at low temperatures corresponding to l-Phe remaining solvated in aqueous solution. At temperatures close to Tgel-lc, a second, shorter lifetime appears that is assigned to l-Phe already embedded within the membrane that becomes hydrated as water starts to permeate the lipid bilayer. This new lifetime is attributed to a conformationally restricted rotamer in the bilayer's polar headgroup region and accounts for up to 30% of the emission amplitude. Results reported for dipalmitoylphosphatidylcholine (DPPC, 16:0) lipid vesicles prove to be general, with similar effects observed for dimyristoylphosphatidylcholine (DMPC, 14:0) and distearoylphosphatidylcholine (DSPC, 18:0) vesicles. Taken together, these results create a complete and compelling picture of how l-Phe associates with model biological membranes. Furthermore, this approach to examining amino acid partitioning into membranes and the resulting solvation forces points to new strategies for studying the structure and chemistry of membrane-soluble peptides and selected membrane proteins.
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Affiliation(s)
- Katelyn M Duncan
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Rhys C Trousdale
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Cristina N Gonzales
- Department of Chemistry, Reed College, Portland, Oregon 97202, United States
| | - William H Steel
- Department of Chemistry, York College of Pennsylvania, York, Pennsylvania 17403, United States
| | - Robert A Walker
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
- Montana Materials Science Program, Montana State University, Bozeman, Montana 59717, United States
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Duncan KM, Steel WH, Walker RA. Amino acids change solute affinity for lipid bilayers. Biophys J 2021; 120:3676-3687. [PMID: 34310940 PMCID: PMC8456291 DOI: 10.1016/j.bpj.2021.07.021] [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: 01/11/2021] [Revised: 06/19/2021] [Accepted: 07/20/2021] [Indexed: 11/26/2022] Open
Abstract
Time-resolved fluorescence and differential scanning calorimetry (DSC) were used to examine how two amino acids, L-phenylalanine (L-PA) and N-acetyl-DL-tryptophan (NAT), affect the temperature-dependent membrane affinity of two structurally similar coumarin solutes for 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) vesicles. The 7-aminocoumarin solutes, coumarin 151 (C151) and coumarin 152 (C152), differ in their substitution at amine position-C151 is a primary amine, and C152 is a tertiary amine-and both solutes show different tendencies to associate with lipid bilayers consistent with differences in their respective log-P-values. Adding L-PA to the DPPC vesicle solution did not change C151's propensity to remain freely solvated in aqueous solution, but C152 showed a greater tendency to partition into the hydrophobic bilayer interior at temperatures below DPPC's gel-liquid crystalline transition temperature (Tgel-lc). This finding is consistent with L-PA's ability to enhance membrane permeability by disrupting chain-chain interactions. Adding NAT to DPPC-vesicle-containing solutions changed C151 and C152 affinity for the DPPC membranes in unexpected ways. DSC data show that NAT interacts strongly with the lipid bilayer, lowering Tgel-lc by up to 2°C at concentrations of 10 mM. These effects disappear when either C151 or C152 is added to solution at concentrations below 10 μM, and Tgel-lc returns to a value consistent with unperturbed DPPC bilayers. Together with DSC results, fluorescence data imply that NAT promotes coumarin adsorption to the vesicle bilayer surface. NAT's effects diminish above Tgel-lc and imply that unlike L-PA, NAT does not penetrate into the bilayer but instead remains adsorbed to the bilayer's exterior. Taken in their entirety, these discoveries suggest that amino acids-and by inference, polypeptides and proteins-change solute affinity for lipid bilayers with specific effects that depend on individualized amino-acid-lipid-bilayer interactions.
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Affiliation(s)
- Katelyn M Duncan
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana
| | - William H Steel
- Department of Chemistry, York College of Pennsylvania, York, Pennsylvania
| | - Robert A Walker
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana; Montana Materials Science Program, Montana State University, Bozeman, Montana.
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Duncan KM, Casey A, Gobrogge CA, Trousdale RC, Piontek SM, Cook MJ, Steel WH, Walker RA. Coumarin Partitioning in Model Biological Membranes: Limitations of log P as a Predictor. J Phys Chem B 2020; 124:8299-8308. [DOI: 10.1021/acs.jpcb.0c06109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Katelyn M. Duncan
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Aoife Casey
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Christine A. Gobrogge
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Rhys C. Trousdale
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Stefan M. Piontek
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Matthew J. Cook
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - William H. Steel
- Department of Chemistry, York College of Pennsylvania, York, Pennsylvania 17403, United States
| | - Robert A. Walker
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
- Montana Materials Science Program, Montana State University, Bozeman, Montana 59717, United States
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Kim YH, Leriche G, Diraviyam K, Koyanagi T, Gao K, Onofrei D, Patterson J, Guha A, Gianneschi N, Holland GP, Gilson MK, Mayer M, Sept D, Yang J. Entropic effects enable life at extreme temperatures. SCIENCE ADVANCES 2019; 5:eaaw4783. [PMID: 31049402 PMCID: PMC6494508 DOI: 10.1126/sciadv.aaw4783] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 03/14/2019] [Indexed: 06/09/2023]
Abstract
Maintaining membrane integrity is a challenge at extreme temperatures. Biochemical synthesis of membrane-spanning lipids is one adaptation that organisms such as thermophilic archaea have evolved to meet this challenge and preserve vital cellular function at high temperatures. The molecular-level details of how these tethered lipids affect membrane dynamics and function, however, remain unclear. Using synthetic monolayer-forming lipids with transmembrane tethers, here, we reveal that lipid tethering makes membrane permeation an entropically controlled process that helps to limit membrane leakage at elevated temperatures relative to bilayer-forming lipid membranes. All-atom molecular dynamics simulations support a view that permeation through membranes made of tethered lipids reduces the torsional entropy of the lipids and leads to tighter lipid packing, providing a molecular interpretation for the increased transition-state entropy of leakage.
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Affiliation(s)
- Young Hun Kim
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Geoffray Leriche
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Karthik Diraviyam
- Department of Biomedical Engineering, Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Takaoki Koyanagi
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kaifu Gao
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - David Onofrei
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182, USA
| | - Joseph Patterson
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Anirvan Guha
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, Fribourg, Switzerland
| | - Nathan Gianneschi
- Departments of Chemistry, Materials Science and Engineering, and Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Gregory P Holland
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182, USA
| | - Michael K Gilson
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Michael Mayer
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, Fribourg, Switzerland
| | - David Sept
- Department of Biomedical Engineering, Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jerry Yang
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
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Link KA, Hsieh CY, Tuladhar A, Chase Z, Wang Z, Wang H, Walker RA. Vibrational studies of saccharide-induced lipid film reorganization at aqueous/air interfaces. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.02.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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6
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Gobrogge CA, Walker RA. Quantifying Solute Partitioning in Phosphatidylcholine Membranes. Anal Chem 2017; 89:12587-12595. [DOI: 10.1021/acs.analchem.7b03964] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christine A. Gobrogge
- Chemistry
and Biochemistry Department, Montana State University, Bozeman, Montana 59717, United States
| | - Robert A. Walker
- Chemistry
and Biochemistry Department, Montana State University, Bozeman, Montana 59717, United States
- Montana
Materials Science Program, Montana State University, Bozeman, Montana 59717, United States
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7
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Affiliation(s)
- Russell Perkins
- University of Colorado Boulder, 215 UCB, Boulder, Colorado 80309, United States
| | - Veronica Vaida
- University of Colorado Boulder, 215 UCB, Boulder, Colorado 80309, United States
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Peschel C, Brehm M, Sebastiani D. Polyphilic Interactions as Structural Driving Force Investigated by Molecular Dynamics Simulation (Project 7). Polymers (Basel) 2017; 9:E445. [PMID: 30965747 PMCID: PMC6418726 DOI: 10.3390/polym9090445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 11/16/2022] Open
Abstract
We investigated the effect of fluorinated molecules on dipalmitoylphosphatidylcholine (DPPC) bilayers by force-field molecular dynamics simulations. In the first step, we developed all-atom force-field parameters for additive molecules in membranes to enable an accurate description of those systems. On the basis of this force field, we performed extensive simulations of various bilayer systems containing different additives. The additive molecules were chosen to be of different size and shape, and they included small molecules such as perfluorinated alcohols, but also more complex molecules. From these simulations, we investigated the structural and dynamic effects of the additives on the membrane properties, as well as the behavior of the additive molecules themselves. Our results are in good agreement with other theoretical and experimental studies, and they contribute to a microscopic understanding of interactions, which might be used to specifically tune membrane properties by additives in the future.
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Affiliation(s)
- Christopher Peschel
- Institute of Chemistry, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, 06120 Halle, Germany.
| | - Martin Brehm
- Institute of Chemistry, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, 06120 Halle, Germany.
| | - Daniel Sebastiani
- Institute of Chemistry, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, 06120 Halle, Germany.
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Brehm M, Saddiq G, Watermann T, Sebastiani D. Influence of Small Fluorophilic and Lipophilic Organic Molecules on Dipalmitoylphosphatidylcholine Bilayers. J Phys Chem B 2017; 121:8311-8321. [DOI: 10.1021/acs.jpcb.7b06520] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Martin Brehm
- Institut für Chemie—Theoretische
Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Ghulam Saddiq
- Institut für Chemie—Theoretische
Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Tobias Watermann
- Institut für Chemie—Theoretische
Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Daniel Sebastiani
- Institut für Chemie—Theoretische
Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
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Gobrogge CA, Kong VA, Walker RA. Temperature-Dependent Partitioning of C152 in Binary Phosphatidylcholine Membranes and Mixed Phosphatidylcholine/Phosphatidylethanolamine Membranes. J Phys Chem B 2017; 121:7889-7898. [DOI: 10.1021/acs.jpcb.7b04831] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Christine A. Gobrogge
- Department of Chemistry and
Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Victoria A. Kong
- Department of Chemistry and
Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Robert A. Walker
- Department of Chemistry and
Biochemistry, Montana State University, Bozeman, Montana 59717, United States
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