1
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Zhang Z, Lynch CJ, Huo Y, Chakraborty S, Cremer PS, Mozhdehi D. Modulating Phase Behavior in Fatty Acid-Modified Elastin-like Polypeptides (FAMEs): Insights into the Impact of Lipid Length on Thermodynamics and Kinetics of Phase Separation. J Am Chem Soc 2024; 146:5383-5392. [PMID: 38353994 PMCID: PMC10910508 DOI: 10.1021/jacs.3c12791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/22/2024] [Accepted: 01/29/2024] [Indexed: 02/29/2024]
Abstract
Although post-translational lipidation is prevalent in eukaryotes, its impact on the liquid-liquid phase separation of disordered proteins is still poorly understood. Here, we examined the thermodynamic phase boundaries and kinetics of aqueous two-phase system (ATPS) formation for a library of elastin-like polypeptides modified with saturated fatty acids of different chain lengths. By systematically altering the physicochemical properties of the attached lipids, we were able to correlate the molecular properties of lipids to changes in the thermodynamic phase boundaries and the kinetic stability of droplets formed by these proteins. We discovered that increasing the chain length lowers the phase separation temperature in a sigmoidal manner due to alterations in the unfavorable interactions between protein and water and changes in the entropy of phase separation. Our kinetic studies unveiled remarkable sensitivity to lipid length, which we propose is due to the temperature-dependent interactions between lipids and the protein. Strikingly, we found that the addition of just a single methylene group is sufficient to allow tuning of these interactions as a function of temperature, with proteins modified with C7-C9 lipids exhibiting non-Arrhenius dependence in their phase separation, a behavior that is absent for both shorter and longer fatty acids. This work advances our theoretical understanding of protein-lipid interactions and opens avenues for the rational design of lipidated proteins in biomedical paradigms, where precise control over the phase separation is pivotal.
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Affiliation(s)
- Zhe Zhang
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Christopher J. Lynch
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Ying Huo
- Department
of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Somya Chakraborty
- Fayetteville-Manlius
High School, Manlius, New York 13104, United States
| | - Paul S. Cremer
- Department
of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Davoud Mozhdehi
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
- BioInspired
Syracuse: Institute for Material and Living Systems, Syracuse University, Syracuse, New York 13244, United States
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2
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Zhao Y, Bharadwaj S, Myers RL, Okur HI, Bui PT, Cao M, Welsh LK, Yang T, Cremer PS, van der Vegt NFA. Solvation Behavior of Elastin-like Polypeptides in Divalent Metal Salt Solutions. J Phys Chem Lett 2023; 14:10113-10118. [PMID: 37921693 DOI: 10.1021/acs.jpclett.3c02476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
The effects of CaCl2 and MgCl2 on the cloud point temperature of two different elastin-like polypeptides (ELPs) were studied using a combination of cloud point measurements, molecular dynamics simulations, and infrared spectroscopy. Changes in the cloud point for the ELPs in aqueous divalent metal cation solutions were primarily governed by two competing interactions: the cation-amide oxygen electrostatic interaction and the hydration of the cation. In particular, Ca2+ cations can more readily shed their hydration shells and directly contact two amide oxygens by the formation of ion bridges. By contrast, Mg2+ cations were more strongly hydrated and preferred to partition toward the amide oxygens along with their hydration shells. In fact, although hydrophilic ELP V5A2G3 was salted-out at low concentrations of MgCl2, it was salted-in at higher salt concentrations. By contrast, CaCl2 salted the ELP sharply out of solution at higher salt concentrations because of the bridging effect.
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Affiliation(s)
- Yani Zhao
- Department of Chemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Swaminath Bharadwaj
- Department of Chemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany
- Department of Chemical Engineering, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Ryan L Myers
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Halil I Okur
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Pho T Bui
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Mengrui Cao
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Lauren K Welsh
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Tinglu Yang
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Paul S Cremer
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania 16802, United States
| | - Nico F A van der Vegt
- Department of Chemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany
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3
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Abstract
Vibrational sum frequency spectroscopy (VSFS) and pressure-area Langmuir trough measurements were used to investigate the binding of alkali metal cations to eicosyl sulfate (ESO4) surfactants in monolayers at the air/water interface. The number density of sulfate groups could be tuned by mixing the anionic surfactant with eicosanol. The equilibrium dissociation constant for K+ to the fatty sulfate interface showed 10 times greater affinity than for Li+ and approximately 3 times greater than for Na+. All three cations formed solvent shared ion pairs when the mole fraction of ESO4 was 0.33 or lower. Above this threshold charge density, Li+ formed contact ion pairs with the sulfate headgroups, presumably via bridging structures. By contrast, K+ only bound to the sulfate moieties in solvent shared ion pairing configurations. The behavior for Na+ was intermediate. These results demonstrate that there is not necessarily a correlation between contact ion pair formation and stronger binding affinity.
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Affiliation(s)
- Kenneth D Judd
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nicole M Gonzalez
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Tinglu Yang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Paul S Cremer
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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4
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Rogers BA, Okur HI, Yan C, Yang T, Heyda J, Cremer PS. Weakly hydrated anions bind to polymers but not monomers in aqueous solutions. Nat Chem 2022; 14:40-45. [PMID: 34725491 DOI: 10.1038/s41557-021-00805-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 08/31/2021] [Indexed: 02/07/2023]
Abstract
Weakly hydrated anions help to solubilize hydrophobic macromolecules in aqueous solutions, but small molecules comprising the same chemical constituents precipitate out when exposed to these ions. Here, this apparent contradiction is resolved by systematically investigating the interactions of NaSCN with polyethylene oxide oligomers and polymers of varying molecular weight. A combination of spectroscopic and computational results reveals that SCN- accumulates near the surface of polymers, but is excluded from monomers. This occurs because SCN- preferentially binds to the centre of macromolecular chains, where the local water hydrogen-bonding network is disrupted. These findings suggest a link between ion-specific effects and theories addressing how hydrophobic hydration is modulated by the size and shape of a hydrophobic entity.
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Affiliation(s)
- Bradley A Rogers
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Halil I Okur
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA.,Department of Chemistry and National Nanotechnology Research Center (UNAM), Bilkent University, Ankara, Turkey
| | - Chuanyu Yan
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Tinglu Yang
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Jan Heyda
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, Dejvice, Czech Republic
| | - Paul S Cremer
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA. .,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA.
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5
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Abstract
Vibrational Stark shifts were explored in aqueous solutions of organic molecules with carbonyl- and nitrile-containing constituents. In many cases, the vibrational resonances from these moieties shifted toward lower frequency as salt was introduced into solution. This is in contrast to the blue-shift that would be expected based upon Onsager's reaction field theory. Salts containing well-hydrated cations like Mg2+ or Li+ led to the most pronounced Stark shift for the carbonyl group, while poorly hydrated cations like Cs+ had the greatest impact on nitriles. Moreover, salts containing I- gave rise to larger Stark shifts than those containing Cl-. Molecular dynamics simulations indicated that cations and anions both accumulate around the probe in an ion- and probe-dependent manner. An electric field was generated by the ion pair, which pointed from the cation to the anion through the vibrational chromophore. This resulted from solvent-shared binding of the ions to the probes, consistent with their positions in the Hofmeister series. The "anti-Onsager" Stark shifts occur in both vibrational spectroscopy and fluorescence measurements.
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Affiliation(s)
| | - Olivia M Cracchiolo
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | | | - Halil I Okur
- Department of Chemistry and National Nanotechnology Research Center (UNAM), Bilkent University, 06800 Ankara, Turkey
| | - Arnaldo L Serrano
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Steven A Corcelli
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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6
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Bruce EE, Bui PT, Rogers BA, Cremer PS, van der Vegt NFA. Addition to "Nonadditive Ion Effects Drive Both Collapse and Swelling of Thermoresponsive Polymers in Water". J Am Chem Soc 2021; 143:2456. [PMID: 33503374 DOI: 10.1021/jacs.1c00210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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7
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Bruce EE, Bui PT, Cao M, Cremer PS, van der Vegt NFA. Contact Ion Pairs in the Bulk Affect Anion Interactions with Poly( N-isopropylacrylamide). J Phys Chem B 2021; 125:680-688. [PMID: 33406822 DOI: 10.1021/acs.jpcb.0c11076] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Salt effects on the solubility of uncharged polymers in aqueous solutions are usually dominated by anions, while the role of the cation with which they are paired is often ignored. In this study, we examine the influence of three aqueous metal iodide salt solutions (LiI, NaI, and CsI) on the phase transition temperature of poly(N-isopropylacrylamide) (PNIPAM) by measuring the turbidity change of the solutions. Weakly hydrated anions, such as iodide, are known to interact with the polymer and thereby lead to salting-in behavior at low salt concentration followed by salting-out behavior at higher salt concentration. When varying the cation type, an unexpected salting-out trend is observed at higher salt concentrations, Cs+ > Na+ > Li+. Using molecular dynamics simulations, it is demonstrated that this originates from contact ion pair formation in the bulk solution, which introduces a competition for iodide ions between the polymer and cations. The weakly hydrated cation, Cs+, forms contact ion pairs with I- in the bulk solution, leading to depletion of CsI from the polymer-water interface. Microscopically, this is correlated with the repulsion of iodide ions from the amide moiety.
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Affiliation(s)
- Ellen E Bruce
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
| | - Pho T Bui
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mengrui Cao
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Paul S Cremer
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nico F A van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
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8
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Drexler CI, Koehler SJ, Myers RL, Lape BA, Elacqua E, Cremer PS. Comment on “Arresting an Unusual Amide Tautomer Using Divalent Cations”. J Phys Chem B 2020; 125:477-478. [DOI: 10.1021/acs.jpcb.0c04272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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Bruce EE, Okur HI, Stegmaier S, Drexler CI, Rogers BA, van der Vegt NFA, Roke S, Cremer PS. Molecular Mechanism for the Interactions of Hofmeister Cations with Macromolecules in Aqueous Solution. J Am Chem Soc 2020; 142:19094-19100. [PMID: 33124825 DOI: 10.1021/jacs.0c07214] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ion identity and concentration influence the solubility of macromolecules. To date, substantial effort has been focused on obtaining a molecular level understanding of specific effects for anions. By contrast, the role of cations has received significantly less attention and the underlying mechanisms by which cations interact with macromolecules remain more elusive. To address this issue, the solubility of poly(N-isopropylacrylamide), a thermoresponsive polymer with an amide moiety on its side chain, was studied in aqueous solutions with a series of nine different cation chloride salts as a function of salt concentration. Phase transition temperature measurements were correlated to molecular dynamics simulations. The results showed that although all cations were on average depleted from the macromolecule/water interface, more strongly hydrated cations were able to locally accumulate around the amide oxygen. These weakly favorable interactions helped to partially offset the salting-out effect. Moreover, the cations approached the interface together with chloride counterions in solvent-shared ion pairs. Because ion pairing was concentration-dependent, the mitigation of the dominant salting-out effect became greater as the salt concentration was increased. Weakly hydrated cations showed less propensity for ion pairing and weaker affinity for the amide oxygen. As such, there was substantially less mitigation of the net salting-out effect for these ions, even at high salt concentrations.
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Affiliation(s)
- Ellen E Bruce
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
| | - Halil I Okur
- Department of Chemistry, and National Nanotechnology Research Center (UNAM), Bilkent University, 06800 Ankara, Turkey.,Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sina Stegmaier
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
| | | | | | - Nico F A van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
| | - Sylvie Roke
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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10
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Poyton MF, Pullanchery S, Sun S, Yang T, Cremer PS. Zn 2+ Binds to Phosphatidylserine and Induces Membrane Blebbing. J Am Chem Soc 2020; 142:18679-18686. [PMID: 33078929 DOI: 10.1021/jacs.0c09103] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Herein, we show that Zn2+ binds to phosphatidylserine (PS) lipids in supported lipid bilayers (SLBs), forming a PS-Zn2+ complex with an equilibrium dissociation constant of ∼100 μM. Significantly, Zn2+ binding to SLBs containing more than 10 mol % PS induces extensive reordering of the bilayer. This reordering is manifest through bright spots of high fluorescence intensity that can be observed when the bilayer contains a dye-labeled lipid. Measurements using atomic force microscopy (AFM) reveal that these spots represent three-dimensional unilamellar blebs. Bleb formation is ion specific, inducible by exposing the bilayer to μM concentrations of Zn2+ but not Mg2+, Cu2+, Co2+, or Mn2+. Moreover, Ca2+ can induce some blebbing at mM concentrations but not nearly as effectively as Zn2+. The interactions of divalent metal cations with PS lipids were further investigated by a combination of vibrational sum frequency spectroscopy (VSFS) and surface pressure-area isotherm measurements. VSFS revealed that Zn2+ and Ca2+ were bound to the phosphate and carboxylate moieties on PS via contact ion pairing, dehydrating the lipid headgroup, whereas Mg2+ and Cu2+ were bound without perturbing the hydration of these functional groups. Additionally, Zn2+ was found to dramatically reduce the area per lipid in lipid monolayers, while Mg2+ and Cu2+ did not. Ca2+ could also reduce the area per lipid but only when significantly higher surface pressures were applied. These measurements suggest that Zn2+ caused lipid blebbing by decreasing the area per lipid on the side of the bilayer to which the salt was exposed. Such findings have implications for blebbing, fusion, oxidation, and related properties of PS-rich membranes in biological systems where Zn2+ concentrations are asymmetrically distributed.
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11
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Dzuricky M, Rogers BA, Shahid A, Cremer PS, Chilkoti A. De novo engineering of intracellular condensates using artificial disordered proteins. Nat Chem 2020; 12:814-825. [PMID: 32747754 DOI: 10.1038/s41557-020-0511-7] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 06/18/2020] [Indexed: 11/09/2022]
Abstract
Phase separation of intrinsically disordered proteins (IDPs) is a remarkable feature of living cells to dynamically control intracellular partitioning. Despite the numerous new IDPs that have been identified, progress towards rational engineering in cells has been limited. To address this limitation, we systematically scanned the sequence space of native IDPs and designed artificial IDPs (A-IDPs) with different molecular weights and aromatic content, which exhibit variable condensate saturation concentrations and temperature cloud points in vitro and in cells. We created A-IDP puncta using these simple principles, which are capable of sequestering an enzyme and whose catalytic efficiency can be manipulated by the molecular weight of the A-IDP. These results provide a robust engineered platform for creating puncta with new, phase-separation-mediated control of biological function in living cells.
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Affiliation(s)
- Michael Dzuricky
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Bradley A Rogers
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Abdulla Shahid
- Department of Computer Science, Duke University, Durham, NC, USA.,Department of Biology, Duke University, Durham, NC, USA
| | - Paul S Cremer
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Ashutosh Chilkoti
- Department of Biomedical Engineering, Duke University, Durham, NC, USA.
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12
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Sun S, Liu C, Rodriguez Melendez D, Yang T, Cremer PS. Immobilization of Phosphatidylinositides Revealed by Bilayer Leaflet Decoupling. J Am Chem Soc 2020; 142:13003-13010. [DOI: 10.1021/jacs.0c03800] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Simou Sun
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Chang Liu
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Danixa Rodriguez Melendez
- Department of Chemistry, University of Puerto Rico at Cayey, Cayey, Puerto Rico 00737, United States
| | - Tinglu Yang
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Paul S. Cremer
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania 16802, United States
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13
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Bakker E, O’Sullivan CK, Cremer PS. Giants in Sensing: A Virtual Issue to Celebrate Five Years of ACS Sensors. ACS Sens 2020; 5:1249-1250. [PMID: 32394712 DOI: 10.1021/acssensors.0c00875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Song W, Joshi H, Chowdhury R, Najem JS, Shen YX, Lang C, Henderson CB, Tu YM, Farell M, Pitz ME, Maranas CD, Cremer PS, Hickey RJ, Sarles SA, Hou JL, Aksimentiev A, Kumar M. Author Correction: Artificial water channels enable fast and selective water permeation through water-wire networks. Nat Nanotechnol 2020; 15:162. [PMID: 31980744 DOI: 10.1038/s41565-020-0640-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Affiliation(s)
- Woochul Song
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Himanshu Joshi
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Ratul Chowdhury
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Joseph S Najem
- Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee, Knoxville, TN, USA
- Department of Mechanical Engineering, The Pennsylvania State University, UniversityPark, PA, USA
| | - Yue-Xiao Shen
- Department of Civil, Environmental, & Construction Engineering, Texas Tech University, Lubbock, TX, USA
| | - Chao Lang
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Codey B Henderson
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Yu-Ming Tu
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Megan Farell
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Megan E Pitz
- Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee, Knoxville, TN, USA
| | - Costas D Maranas
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Paul S Cremer
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Robert J Hickey
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Stephen A Sarles
- Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee, Knoxville, TN, USA
| | - Jun-Li Hou
- Department of Chemistry, Fudan University, Shanghai, China
| | - Aleksei Aksimentiev
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Manish Kumar
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, Austin, TX, USA.
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15
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Song W, Joshi H, Chowdhury R, Najem JS, Shen YX, Lang C, Henderson CB, Tu YM, Farell M, Pitz ME, Maranas CD, Cremer PS, Hickey RJ, Sarles SA, Hou JL, Aksimentiev A, Kumar M. Artificial water channels enable fast and selective water permeation through water-wire networks. Nat Nanotechnol 2020; 15:73-79. [PMID: 31844288 PMCID: PMC7008941 DOI: 10.1038/s41565-019-0586-8] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Accepted: 11/04/2019] [Indexed: 05/09/2023]
Abstract
Artificial water channels are synthetic molecules that aim to mimic the structural and functional features of biological water channels (aquaporins). Here we report on a cluster-forming organic nanoarchitecture, peptide-appended hybrid[4]arene (PAH[4]), as a new class of artificial water channels. Fluorescence experiments and simulations demonstrated that PAH[4]s can form, through lateral diffusion, clusters in lipid membranes that provide synergistic membrane-spanning paths for a rapid and selective water permeation through water-wire networks. Quantitative transport studies revealed that PAH[4]s can transport >109 water molecules per second per molecule, which is comparable to aquaporin water channels. The performance of these channels exceeds the upper bound limit of current desalination membranes by a factor of ~104, as illustrated by the water/NaCl permeability-selectivity trade-off curve. PAH[4]'s unique properties of a high water/solute permselectivity via cooperative water-wire formation could usher in an alternative design paradigm for permeable membrane materials in separations, energy production and barrier applications.
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Affiliation(s)
- Woochul Song
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Himanshu Joshi
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Ratul Chowdhury
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Joseph S Najem
- Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee, Knoxville, TN, USA
- Department of Mechanical Engineering, The Pennsylvania State University, UniversityPark, PA, USA
| | - Yue-Xiao Shen
- Department of Civil, Environmental, & Construction Engineering, Texas Tech University, Lubbock, TX, USA
| | - Chao Lang
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Codey B Henderson
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Yu-Ming Tu
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Megan Farell
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Megan E Pitz
- Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee, Knoxville, TN, USA
| | - Costas D Maranas
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Paul S Cremer
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Robert J Hickey
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Stephen A Sarles
- Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee, Knoxville, TN, USA
| | - Jun-Li Hou
- Department of Chemistry, Fudan University, Shanghai, China
| | - Aleksei Aksimentiev
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Manish Kumar
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, Austin, TX, USA.
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16
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Somasundar A, Ghosh S, Mohajerani F, Massenburg LN, Yang T, Cremer PS, Velegol D, Sen A. Positive and negative chemotaxis of enzyme-coated liposome motors. Nat Nanotechnol 2019; 14:1129-1134. [PMID: 31740796 DOI: 10.1038/s41565-019-0578-8] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 10/15/2019] [Indexed: 06/10/2023]
Abstract
The ability of cells or cell components to move in response to chemical signals is critical for the survival of living systems. This motion arises from harnessing free energy from enzymatic catalysis. Artificial model protocells derived from phospholipids and other amphiphiles have been made and their enzymatic-driven motion has been observed. However, control of directionality based on chemical cues (chemotaxis) has been difficult to achieve. Here we show both positive or negative chemotaxis of liposomal protocells. The protocells move autonomously by interacting with concentration gradients of either substrates or products in enzyme catalysis, or Hofmeister salts. We hypothesize that the propulsion mechanism is based on the interplay between enzyme-catalysis-induced positive chemotaxis and solute-phospholipid-based negative chemotaxis. Controlling the extent and direction of chemotaxis holds considerable potential for designing cell mimics and delivery vehicles that can reconfigure their motion in response to environmental conditions.
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Affiliation(s)
- Ambika Somasundar
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Subhadip Ghosh
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Farzad Mohajerani
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Lynnicia N Massenburg
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Tinglu Yang
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Paul S Cremer
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA.
| | - Darrell Velegol
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA.
| | - Ayusman Sen
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA.
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17
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Drexler CI, Miller TC, Rogers BA, Li YC, Daly CA, Yang T, Corcelli SA, Cremer PS. Counter Cations Affect Transport in Aqueous Hydroxide Solutions with Ion Specificity. J Am Chem Soc 2019; 141:6930-6936. [DOI: 10.1021/jacs.8b13458] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
| | - Tierney C. Miller
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | | | | | - Clyde A. Daly
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | | | - Steven A. Corcelli
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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18
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Bruce EE, Bui PT, Rogers BA, Cremer PS, van der Vegt NFA. Nonadditive Ion Effects Drive Both Collapse and Swelling of Thermoresponsive Polymers in Water. J Am Chem Soc 2019; 141:6609-6616. [DOI: 10.1021/jacs.9b00295] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Ellen E. Bruce
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, D-64287 Darmstadt, Germany
| | - Pho T. Bui
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Bradley A. Rogers
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Paul S. Cremer
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nico F. A. van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, D-64287 Darmstadt, Germany
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19
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Abstract
Sphingosine-1-phosphate (S1P) is a sphingolipid metabolite that is thought to participate in the regulation of many physiological processes and may play a key role in several diseases. Herein, we found that Cu2+ binds tightly to supported lipid bilayers (SLBs) containing S1P. Specifically, we demonstrated via fluorescence assays that Cu2+-S1P binding was bivalent and sensitive to the concentration of S1P in the SLB. In fact, the apparent equilibrium dissociation constant, KDApp, tightened by a factor of 132 from 4.5 μM to 34 nM as the S1P density was increased from 5.0 to 20 mol %. A major driving force for this apparent tightening was the more negative surface potential with increasing S1P concentration. This potential remained unaltered upon Cu2+ binding at pH 7.4 because two protons were released for every Cu2+ that bound. At pH 5.4, however, Cu2+ could not outcompete protons for the amine and no binding occurred. Moreover, at pH 9.4, the amine was partially deprotonated before Cu2+ binding and the surface potential became more positive on binding. The results for Cu2+-S1P binding were reminiscent of those for Cu2+-phosphatidylserine binding, where a carboxylate group helped to deprotonate the amine. In the case of S1P, however, the phosphate needed to bear two negative charges to facilitate amine deprotonation in the presence of Cu2+.
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Affiliation(s)
| | - Adriana N Santiago-Ruiz
- Department of Chemistry , The University of Puerto Rico , Cayey , Puerto Rico 00736 , United States
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20
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Pullanchery S, Yang T, Cremer PS. Introduction of Positive Charges into Zwitterionic Phospholipid Monolayers Disrupts Water Structure Whereas Negative Charges Enhances It. J Phys Chem B 2018; 122:12260-12270. [DOI: 10.1021/acs.jpcb.8b08476] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Okur H, Drexler CI, Tyrode E, Cremer PS, Roke S. The Jones-Ray Effect Is Not Caused by Surface-Active Impurities. J Phys Chem Lett 2018; 9:6739-6743. [PMID: 30398354 PMCID: PMC6287224 DOI: 10.1021/acs.jpclett.8b02957] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 11/06/2018] [Indexed: 05/20/2023]
Abstract
Pure aqueous electrolyte solutions display a minimum in surface tension at concentrations of 2 ± 1 mM. This effect has been a source of controversy since it was first reported by Jones and Ray in the 1930s. The Jones-Ray effect has frequently been dismissed as an artifact linked to the presence of surface-active impurities. Herein we systematically consider the effect of surface-active impurities by purposely adding nanomolar concentrations of surfactants to dilute electrolyte solutions. Trace amounts of surfactant are indeed found to decrease the surface tension and influence the surface chemistry. However, surfactants can be removed by repeated aspiration and stirring cycles, which eventually deplete the surfactant from solution, creating a pristine surface. Upon following this cleaning procedure, a reduction in the surface tension by millimolar concentrations of salt is still observed. Consequently, we demonstrate that the Jones-Ray effect is not caused by surface-active impurities.
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Affiliation(s)
- Halil
I. Okur
- Laboratory
for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI)
and Institute of Materials Science (IMX), School of Engineering (STI),
and Lausanne Center for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Chad I. Drexler
- Department of Chemistry and Biochemistry and
Molecular Biology, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - Eric Tyrode
- Laboratory
for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI)
and Institute of Materials Science (IMX), School of Engineering (STI),
and Lausanne Center for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Department
of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology
and Health, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
| | - Paul S. Cremer
- Department of Chemistry and Biochemistry and
Molecular Biology, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - Sylvie Roke
- Laboratory
for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI)
and Institute of Materials Science (IMX), School of Engineering (STI),
and Lausanne Center for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- E-mail:
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22
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Abstract
Ibuprofen (IBU) interacts with phosphatidylcholine membranes in three distinct steps as a function of concentration. In a first step (<10 μM), IBU electrostatically adsorbs to the lipid headgroups and gradually decreases the interfacial potential. This first step helps to facilitate the second step (10-300 μM), in which hydrophobic insertion of the drug occurs. The second step disrupts the packing of the lipid acyl chains and expands the area per lipid. In a final step, above 300 μM IBU, the lipid membrane begins to solubilize, resulting in a detergent-like effect. The results described herein were obtained by a combination of fluorescence binding assays, vibrational sum frequency spectroscopy, and Langmuir monolayer compression experiments. By introducing trimethylammonium-propane, phosphatidylglycerol, and phosphatidylethanolamine lipids as well as cholesterol, we demonstrated that both the chemistry of the lipid headgroups and the packing of lipid acyl chains can substantially influence the interactions between IBU and the membranes. Moreover, different membrane chemistries can alter particular steps in the binding interaction.
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Affiliation(s)
- Simou Sun
- Department of Chemistry , Penn State University , University Park , State College , Pennsylvania 16802 , United States
| | - Anne M Sendecki
- Department of Chemistry , Penn State University , University Park , State College , Pennsylvania 16802 , United States
| | - Saranya Pullanchery
- Department of Chemistry , Penn State University , University Park , State College , Pennsylvania 16802 , United States
| | - Da Huang
- Department of Chemistry , Penn State University , University Park , State College , Pennsylvania 16802 , United States
| | - Tinglu Yang
- Department of Chemistry , Penn State University , University Park , State College , Pennsylvania 16802 , United States
| | - Paul S Cremer
- Department of Chemistry , Penn State University , University Park , State College , Pennsylvania 16802 , United States
- Department of Biochemistry and Molecular Biology , Penn State University , State College , Pennsylvania 16802 , United States
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23
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Shen YX, Song W, Barden DR, Ren T, Lang C, Feroz H, Henderson CB, Saboe PO, Tsai D, Yan H, Butler PJ, Bazan GC, Phillip WA, Hickey RJ, Cremer PS, Vashisth H, Kumar M. Publisher Correction: Achieving high permeability and enhanced selectivity for Angstrom-scale separations using artificial water channel membranes. Nat Commun 2018; 9:3304. [PMID: 30108220 PMCID: PMC6092424 DOI: 10.1038/s41467-018-05447-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Yue-Xiao Shen
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.,Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Woochul Song
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - D Ryan Barden
- Department of Chemical Engineering, University of New Hampshire, Durham, NH, 03824, USA
| | - Tingwei Ren
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Chao Lang
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Hasin Feroz
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Codey B Henderson
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Patrick O Saboe
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Daniel Tsai
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Hengjing Yan
- Center for Polymers and Organic Solids, University of California at Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Peter J Butler
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Guillermo C Bazan
- Center for Polymers and Organic Solids, University of California at Santa Barbara, Santa Barbara, CA, 93106, USA
| | - William A Phillip
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Robert J Hickey
- Department of Material Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Paul S Cremer
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Harish Vashisth
- Department of Chemical Engineering, University of New Hampshire, Durham, NH, 03824, USA
| | - Manish Kumar
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA. .,Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA. .,Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
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24
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Shen YX, Song W, Barden DR, Ren T, Lang C, Feroz H, Henderson CB, Saboe PO, Tsai D, Yan H, Butler PJ, Bazan GC, Phillip WA, Hickey RJ, Cremer PS, Vashisth H, Kumar M. Achieving high permeability and enhanced selectivity for Angstrom-scale separations using artificial water channel membranes. Nat Commun 2018; 9:2294. [PMID: 29895901 PMCID: PMC5997692 DOI: 10.1038/s41467-018-04604-y] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 05/09/2018] [Indexed: 01/05/2023] Open
Abstract
Synthetic polymer membranes, critical to diverse energy-efficient separations, are subject to permeability-selectivity trade-offs that decrease their overall efficacy. These trade-offs are due to structural variations (e.g., broad pore size distributions) in both nonporous membranes used for Angstrom-scale separations and porous membranes used for nano to micron-scale separations. Biological membranes utilize well-defined Angstrom-scale pores to provide exceptional transport properties and can be used as inspiration to overcome this trade-off. Here, we present a comprehensive demonstration of such a bioinspired approach based on pillar[5]arene artificial water channels, resulting in artificial water channel-based block copolymer membranes. These membranes have a sharp selectivity profile with a molecular weight cutoff of ~ 500 Da, a size range challenging to achieve with current membranes, while achieving a large improvement in permeability (~65 L m-2 h-1 bar-1 compared with 4-7 L m-2 h-1 bar-1) over similarly rated commercial membranes.
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Affiliation(s)
- Yue-Xiao Shen
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Woochul Song
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - D Ryan Barden
- Department of Chemical Engineering, University of New Hampshire, Durham, NH, 03824, USA
| | - Tingwei Ren
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Chao Lang
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Hasin Feroz
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Codey B Henderson
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Patrick O Saboe
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Daniel Tsai
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Hengjing Yan
- Center for Polymers and Organic Solids, University of California at Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Peter J Butler
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Guillermo C Bazan
- Center for Polymers and Organic Solids, University of California at Santa Barbara, Santa Barbara, CA, 93106, USA
| | - William A Phillip
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Robert J Hickey
- Department of Material Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Paul S Cremer
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Harish Vashisth
- Department of Chemical Engineering, University of New Hampshire, Durham, NH, 03824, USA
| | - Manish Kumar
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
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25
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Shengjuler D, Chan YM, Sun S, Moustafa IM, Li ZL, Gohara DW, Buck M, Cremer PS, Boehr DD, Cameron CE. The RNA-Binding Site of Poliovirus 3C Protein Doubles as a Phosphoinositide-Binding Domain. Structure 2017; 25:1875-1886.e7. [PMID: 29211985 PMCID: PMC5728361 DOI: 10.1016/j.str.2017.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/18/2017] [Accepted: 11/01/2017] [Indexed: 12/31/2022]
Abstract
Some viruses use phosphatidylinositol phosphate (PIP) to mark membranes used for genome replication or virion assembly. PIP-binding motifs of cellular proteins do not exist in viral proteins. Molecular-docking simulations revealed a putative site of PIP binding to poliovirus (PV) 3C protein that was validated using nuclear magnetic resonance spectroscopy. The PIP-binding site was located on a highly dynamic α helix, which also functions in RNA binding. Broad PIP-binding activity was observed in solution using a fluorescence polarization assay or in the context of a lipid bilayer using an on-chip, fluorescence assay. All-atom molecular dynamics simulations of the 3C protein-membrane interface revealed PIP clustering and perhaps PIP-dependent conformations. PIP clustering was mediated by interaction with residues that interact with the RNA phosphodiester backbone. We conclude that 3C binding to membranes will be determined by PIP abundance. We suggest that the duality of function observed for 3C may extend to RNA-binding proteins of other viruses.
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Affiliation(s)
- Djoshkun Shengjuler
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Yan Mei Chan
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Simou Sun
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Ibrahim M Moustafa
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Zhen-Lu Li
- Department of Physiology and Biophysics, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - David W Gohara
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Matthias Buck
- Department of Physiology and Biophysics, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Paul S Cremer
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA; Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - David D Boehr
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Craig E Cameron
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
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26
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Sendecki AM, Poyton MF, Baxter AJ, Yang T, Cremer PS. Supported Lipid Bilayers with Phosphatidylethanolamine as the Major Component. Langmuir 2017; 33:13423-13429. [PMID: 29119796 DOI: 10.1021/acs.langmuir.7b02323] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Phosphatidylethanolamine (PE) is notoriously difficult to incorporate into model membrane systems, such as fluid supported lipid bilayers (SLBs), at high concentrations because of its intrinsic negative curvature. Using fluorescence-based techniques, we demonstrate that having fewer sites of unsaturation in the lipid tails leads to high-quality SLBs because these lipids help to minimize the curvature. Moreover, shorter saturated chains can help maintain the membranes in the fluid phase. Using these two guidelines, we find that up to 70 mol % PE can be incorporated into SLBs at room temperature and up to 90 mol % PE can be incorporated at 37 °C. Curiously, conditions under which three-dimensional tubules project outward from the planar surface as well as conditions under which domain formation occurs can be found. We have employed these model membrane systems to explore the ability of Ni2+ to bind to PE. It was found that this transition metal ion binds 1000-fold tighter to PE than to phosphatidylcholine lipids. In the future, this platform could be exploited to monitor the binding of other transition metal ions or the binding of antimicrobial peptides. It could also be employed to explore the physical properties of PE-containing membranes, such as phase domain behavior and intermolecular hydrogen bonding.
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Affiliation(s)
- Anne M Sendecki
- Department of Chemistry and ‡Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Matthew F Poyton
- Department of Chemistry and ‡Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Alexis J Baxter
- Department of Chemistry and ‡Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Tinglu Yang
- Department of Chemistry and ‡Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Paul S Cremer
- Department of Chemistry and ‡Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
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27
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Abstract
Numerous cellular proteins interact with membrane surfaces to affect essential cellular processes. These interactions can be directed towards a specific lipid component within a membrane, as in the case of phosphoinositides (PIPs), to ensure specific subcellular localization and/or activation. PIPs and cellular PIP-binding domains have been studied extensively to better understand their role in cellular physiology. We applied a pH modulation assay on supported lipid bilayers (SLBs) as a tool to study protein-PIP interactions. In these studies, pH sensitive ortho-Sulforhodamine B conjugated phosphatidylethanolamine is used to detect protein-PIP interactions. Upon binding of a protein to a PIP-containing membrane surface, the interfacial potential is modulated (i.e. change in local pH), shifting the protonation state of the probe. A case study of the successful usage of the pH modulation assay is presented by using phospholipase C delta1 Pleckstrin Homology (PLC-δ1 PH) domain and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) interaction as an example. The apparent dissociation constant (Kd,app) for this interaction was 0.39 ± 0.05 µM, similar to Kd,app values obtained by others. As previously observed, the PLC-δ1 PH domain is PI(4,5)P2 specific, shows weaker binding towards phosphatidylinositol 4-phosphate, and no binding to pure phosphatidylcholine SLBs. The PIP-on-a-chip assay is advantageous over traditional PIP-binding assays, including but not limited to low sample volume and no ligand/receptor labeling requirements, the ability to test high- and low-affinity membrane interactions with both small and large molecules, and improved signal to noise ratio. Accordingly, the usage of the PIP-on-a-chip approach will facilitate the elucidation of mechanisms of a wide range of membrane interactions. Furthermore, this method could potentially be used in identifying therapeutics that modulate protein's capacity to interact with membranes.
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Affiliation(s)
- Djoshkun Shengjuler
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University;
| | - Simou Sun
- Department of Chemistry, The Pennsylvania State University
| | - Paul S Cremer
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University; Department of Chemistry, The Pennsylvania State University;
| | - Craig E Cameron
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University;
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28
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Zhao Z, Cao Y, Cai Y, Yang J, He X, Nordlander P, Cremer PS. Oblique Colloidal Lithography for the Fabrication of Nonconcentric Features. ACS Nano 2017; 11:6594-6604. [PMID: 28704035 DOI: 10.1021/acsnano.6b07867] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Herein, we describe the development of oblique colloidal lithography (OCL) and establish a systematic patterning strategy for creating libraries of nanosized nonconcentric plasmonic structures. This strategy combines OCL, capillary force lithography, and several wet and ion etching steps. Hexagonal arrays of nonconcentric gold features were created on glass substrates with highly controllable geometric parameters. The size, geometry, and eccentricity of the gold features could be independently tuned by controlling the experimental conditions. Gaps within surface elements could be shrunk to as small as 30 nm, while the total patterned area was about l cm2. The goal was to devise a method that offers a high degree of control over the resolution and morphology of asymmetric structures without the need to resort to electron beam lithography. This technique also enabled the development of numerous surface patterns through the stepwise fabrication of separate elements. Complex features, including dots-surrounded nonconcentric targets, nonconcentric hexagram-disks, and nonconcentric annular aperture arrays, were demonstrated, and their optical properties were characterized. Indeed, spectroscopic studies and FDTD simulations demonstrated that Fano resonances could readily be generated by the nonconcentric gold features. Consequently, our patterning strategy should enable the high-throughput investigation of plasmonic coupling and Fano resonances as a function of the physical parameters of the elements within the nanopattern array.
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Affiliation(s)
- Zhi Zhao
- Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States
- School for Engineering of Matter, Transport and Energy, Arizona State University , 781 E. Terrace Road, Tempe, Arizona 85287, United States
| | - Yang Cao
- Department of Physics and Astronomy, Rice University , Houston, Texas 77251, United States
| | - Yangjun Cai
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University , University Park, Pennsylvania 16803, United States
| | - Jian Yang
- Department of Physics and Astronomy, Rice University , Houston, Texas 77251, United States
| | - Ximin He
- School for Engineering of Matter, Transport and Energy, Arizona State University , 781 E. Terrace Road, Tempe, Arizona 85287, United States
| | - Peter Nordlander
- Department of Physics and Astronomy, Rice University , Houston, Texas 77251, United States
| | - Paul S Cremer
- Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University , University Park, Pennsylvania 16803, United States
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29
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Bilkova E, Pleskot R, Rissanen S, Sun S, Czogalla A, Cwiklik L, Róg T, Vattulainen I, Cremer PS, Jungwirth P, Coskun Ü. Calcium Directly Regulates Phosphatidylinositol 4,5-Bisphosphate Headgroup Conformation and Recognition. J Am Chem Soc 2017; 139:4019-4024. [PMID: 28177616 PMCID: PMC5364432 DOI: 10.1021/jacs.6b11760] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The orchestrated recognition of phosphoinositides and concomitant intracellular release of Ca2+ is pivotal to almost every aspect of cellular processes, including membrane homeostasis, cell division and growth, vesicle trafficking, as well as secretion. Although Ca2+ is known to directly impact phosphoinositide clustering, little is known about the molecular basis for this or its significance in cellular signaling. Here, we study the direct interaction of Ca2+ with phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), the main lipid marker of the plasma membrane. Electrokinetic potential measurements of PI(4,5)P2 containing liposomes reveal that Ca2+ as well as Mg2+ reduce the zeta potential of liposomes to nearly background levels of pure phosphatidylcholine membranes. Strikingly, lipid recognition by the default PI(4,5)P2 lipid sensor, phospholipase C delta 1 pleckstrin homology domain (PLC δ1-PH), is completely inhibited in the presence of Ca2+, while Mg2+ has no effect with 100 nm liposomes and modest effect with giant unilamellar vesicles. Consistent with biochemical data, vibrational sum frequency spectroscopy and atomistic molecular dynamics simulations reveal how Ca2+ binding to the PI(4,5)P2 headgroup and carbonyl regions leads to confined lipid headgroup tilting and conformational rearrangements. We rationalize these findings by the ability of calcium to block a highly specific interaction between PLC δ1-PH and PI(4,5)P2, encoded within the conformational properties of the lipid itself. Our studies demonstrate the possibility that switchable phosphoinositide conformational states can serve as lipid recognition and controlled cell signaling mechanisms.
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Affiliation(s)
- Eva Bilkova
- Paul Langerhans Institute Dresden of the Helmholtz Zentrum München at the University Hospital and Faculty of Medicine Carl Gustav Carus of TU Dresden, Technische Universität Dresden , Fetscher Strasse 74, 01307 Dresden, Germany.,German Center for Diabetes Research (DZD e.V.) , Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Roman Pleskot
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo náměstí 2, 16610 Prague 6, Czech Republic.,Institute of Experimental Botany, Academy of Sciences of the Czech Republic , v.v.i., Rozvojová 263, 16502 Prague 6, Czech Republic
| | - Sami Rissanen
- Department of Physics, Tampere University of Technology , P.O. Box 692, FI-33101 Tampere, Finland
| | | | - Aleksander Czogalla
- Paul Langerhans Institute Dresden of the Helmholtz Zentrum München at the University Hospital and Faculty of Medicine Carl Gustav Carus of TU Dresden, Technische Universität Dresden , Fetscher Strasse 74, 01307 Dresden, Germany.,Laboratory of Cytobiochemistry, Faculty of Biotechnology, University of Wrocław , Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Lukasz Cwiklik
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo náměstí 2, 16610 Prague 6, Czech Republic.,J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , v.v.i., Dolejskova 3, 18223 Prague 8, Czech Republic
| | - Tomasz Róg
- Department of Physics, Tampere University of Technology , P.O. Box 692, FI-33101 Tampere, Finland.,Department of Physics, University of Helsinki , P.O. Box 64, FI-00014, Helsinki, Finland
| | - Ilpo Vattulainen
- Department of Physics, Tampere University of Technology , P.O. Box 692, FI-33101 Tampere, Finland.,Department of Physics, University of Helsinki , P.O. Box 64, FI-00014, Helsinki, Finland.,MEMPHYS- Center for Biomembrane Physics, University of Southern Denmark , DK-5230 Odense, Denmark
| | | | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo náměstí 2, 16610 Prague 6, Czech Republic.,Department of Physics, Tampere University of Technology , P.O. Box 692, FI-33101 Tampere, Finland
| | - Ünal Coskun
- Paul Langerhans Institute Dresden of the Helmholtz Zentrum München at the University Hospital and Faculty of Medicine Carl Gustav Carus of TU Dresden, Technische Universität Dresden , Fetscher Strasse 74, 01307 Dresden, Germany.,German Center for Diabetes Research (DZD e.V.) , Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
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Okur HI, Hladílková J, Rembert KB, Cho Y, Heyda J, Dzubiella J, Cremer PS, Jungwirth P. Beyond the Hofmeister Series: Ion-Specific Effects on Proteins and Their Biological Functions. J Phys Chem B 2017; 121:1997-2014. [PMID: 28094985 DOI: 10.1021/acs.jpcb.6b10797] [Citation(s) in RCA: 386] [Impact Index Per Article: 55.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ions differ in their ability to salt out proteins from solution as expressed in the lyotropic or Hofmeister series of cations and anions. Since its first formulation in 1888, this series has been invoked in a plethora of effects, going beyond the original salting out/salting in idea to include enzyme activities and the crystallization of proteins, as well as to processes not involving proteins like ion exchange, the surface tension of electrolytes, or bubble coalescence. Although it has been clear that the Hofmeister series is intimately connected to ion hydration in homogeneous and heterogeneous environments and to ion pairing, its molecular origin has not been fully understood. This situation could have been summarized as follows: Many chemists used the Hofmeister series as a mantra to put a label on ion-specific behavior in various environments, rather than to reach a molecular level understanding and, consequently, an ability to predict a particular effect of a given salt ion on proteins in solutions. In this Feature Article we show that the cationic and anionic Hofmeister series can now be rationalized primarily in terms of specific interactions of salt ions with the backbone and charged side chain groups at the protein surface in solution. At the same time, we demonstrate the limitations of separating Hofmeister effects into independent cationic and anionic contributions due to the electroneutrality condition, as well as specific ion pairing, leading to interactions of ions of opposite polarity. Finally, we outline the route beyond Hofmeister chemistry in the direction of understanding specific roles of ions in various biological functionalities, where generic Hofmeister-type interactions can be complemented or even overruled by particular steric arrangements in various ion binding sites.
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Affiliation(s)
- Halil I Okur
- Laboratory for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Jana Hladílková
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences , Flemingovo nam. 2, 16610 Prague 6, Czech Republic.,Division of Theoretical Chemistry, Lund University , P.O.B. 124, SE-22100 Lund, Sweden
| | | | - Younhee Cho
- Department of Chemistry, Texas A&M University , College Station 77843, Texas, United States
| | - Jan Heyda
- Institut für Weiche Materie und Funktionale Materialien, Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner Platz 1, 14109 Berlin, Germany.,Department of Physical Chemistry, University of Chemistry and Technology, Prague , Technická 5, 16628 Prague 6, Czech Republic
| | - Joachim Dzubiella
- Institut für Weiche Materie und Funktionale Materialien, Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner Platz 1, 14109 Berlin, Germany.,Institut für Physik, Humboldt-Universität zu Berlin , Newtonstrasse 15, 12489 Berlin, Germany
| | | | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences , Flemingovo nam. 2, 16610 Prague 6, Czech Republic
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31
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Heyda J, Okur HI, Hladílková J, Rembert KB, Hunn W, Yang T, Dzubiella J, Jungwirth P, Cremer PS. Guanidinium can both Cause and Prevent the Hydrophobic Collapse of Biomacromolecules. J Am Chem Soc 2017; 139:863-870. [PMID: 28054487 PMCID: PMC5499822 DOI: 10.1021/jacs.6b11082] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
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A combination of Fourier transform
infrared and phase transition
measurements as well as molecular computer simulations, and thermodynamic
modeling were performed to probe the mechanisms by which guanidinium
(Gnd+) salts influence the stability of the collapsed versus
uncollapsed state of an elastin-like polypeptide (ELP), an uncharged
thermoresponsive polymer. We found that the cation’s action
was highly dependent upon the counteranion with which it was paired.
Specifically, Gnd+ was depleted from the ELP/water interface
and was found to stabilize the collapsed state of the macromolecule
when paired with well-hydrated anions such as SO42–. Stabilization in this case occurred via an excluded volume (or
depletion) effect, whereby SO42– was
strongly partitioned away from the ELP/water interface. Intriguingly,
at low salt concentrations, Gnd+ was also found to stabilize
the collapsed state of the ELP when paired with SCN–, which is a strong binder for the ELP. In this case, the anion and
cation were both found to be enriched in the collapsed state of the
polymer. The collapsed state was favored because the Gnd+ cross-linked the polymer chains together. Moreover, the anion helped
partition Gnd+ to the polymer surface. At higher salt concentrations
(>1.5 M), GndSCN switched to stabilizing the uncollapsed state
because
a sufficient amount of Gnd+ and SCN– partitioned
to the polymer surface to prevent cross-linking from occurring. Finally,
in a third case, it was found that salts which interacted in an intermediate
fashion with the polymer (e.g., GndCl) favored the uncollapsed conformation
at all salt concentrations. These results provide a detailed, molecular-level,
mechanistic picture of how Gnd+ influences the stability
of polypeptides in three distinct physical regimes by varying the
anion. It also helps explain the circumstances under which guanidinium
salts can act as powerful and versatile protein denaturants.
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Affiliation(s)
- Jan Heyda
- Institut für Weiche Materie und Funktionale Materialien, Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner Platz 1, 14109 Berlin, Germany.,Physical Chemistry Department, University of Chemistry and Technology, Prague , Technicka 5, 16628 Prague 6, Czech Republic
| | | | - Jana Hladílková
- Division of Theoretical Chemistry, Lund University , POB 124, 22 100 Lund, Sweden.,Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | | | - William Hunn
- Chemistry Department, Texas A&M University , 3255 TAMU, College Station, Texas 77843, United States
| | | | - Joachim Dzubiella
- Institut für Weiche Materie und Funktionale Materialien, Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner Platz 1, 14109 Berlin, Germany.,Institut für Physik, Humboldt-Universität zu Berlin , Newtonstr. 15, 12489 Berlin, Germany
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo nám. 2, 16610 Prague 6, Czech Republic
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Kusler K, Odoh SO, Silakov A, Poyton MF, Pullanchery S, Cremer PS, Gagliardi L. What Is the Preferred Conformation of Phosphatidylserine–Copper(II) Complexes? A Combined Theoretical and Experimental Investigation. J Phys Chem B 2016; 120:12883-12889. [DOI: 10.1021/acs.jpcb.6b10675] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kari Kusler
- Department
of Chemistry, Chemical Theory Center, and Minnesota Supercomputing
Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Samuel O. Odoh
- Department
of Chemistry, Chemical Theory Center, and Minnesota Supercomputing
Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Alexey Silakov
- Department
of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Matthew F. Poyton
- Department
of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Saranya Pullanchery
- Department
of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Paul S. Cremer
- Department
of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Laura Gagliardi
- Department
of Chemistry, Chemical Theory Center, and Minnesota Supercomputing
Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
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33
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Robison AD, Sun S, Poyton MF, Johnson GA, Pellois JP, Jungwirth P, Vazdar M, Cremer PS. Polyarginine Interacts More Strongly and Cooperatively than Polylysine with Phospholipid Bilayers. J Phys Chem B 2016; 120:9287-96. [PMID: 27571288 PMCID: PMC5912336 DOI: 10.1021/acs.jpcb.6b05604] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The interactions of two highly positively charged short peptide sequences with negatively charged lipid bilayers were explored by fluorescence binding assays and all-atom molecular dynamics simulations. The bilayers consisted of mixtures of phosphatidylglycerol (PG) and phosphatidylcholine (PC) lipids as well as a fluorescence probe that was sensitive to the interfacial potential. The first peptide contained nine arginine repeats (Arg9), and the second one had nine lysine repeats (Lys9). The experimentally determined apparent dissociation constants and Hill cooperativity coefficients demonstrated that the Arg9 peptides exhibited weakly anticooperative binding behavior at the bilayer interface at lower PG concentrations, but this anticooperative effect vanished once the bilayers contained at least 20 mol % PG. By contrast, Lys9 peptides showed strongly anticooperative binding behavior at all PG concentrations, and the dissociation constants with Lys9 were approximately 2 orders of magnitude higher than with Arg9. Moreover, only arginine-rich peptides could bind to the phospholipid bilayers containing just PC lipids. These results along with the corresponding molecular dynamics simulations suggested two important distinctions between the behavior of Arg9 and Lys9 that led to these striking differences in binding and cooperativity. First, the interactions of the guanidinium moieties on the Arg side chains with the phospholipid head groups were stronger than for the amino group. This helped facilitate stronger Arg9 binding at all PG concentrations that were tested. However, at PG concentrations of 20 mol % or greater, the Arg9 peptides came into sufficiently close proximity with each other so that favorable like-charge pairing between the guanidinium moieties could just offset the long-range electrostatic repulsions. This led to Arg9 aggregation at the bilayer surface. By contrast, Lys9 molecules experienced electrostatic repulsion from each other at all PG concentrations. These insights may help explain the propensity for cell penetrating peptides containing arginine to more effectively cross cell membranes in comparison with lysine-rich peptides.
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Affiliation(s)
| | | | | | | | | | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo nám. 2, Prague 6 16610, Czech Republic
- Department of Physics, Tampere University of Technology , P.O. Box 692, FI-33101 Tampere, Finland
| | - Mario Vazdar
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute , P.O.B. 180, HR-10002 Zagreb, Croatia
- Department of Physics, Tampere University of Technology , P.O. Box 692, FI-33101 Tampere, Finland
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34
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Chen Y, Okur HI, Gomopoulos N, Macias-Romero C, Cremer PS, Petersen PB, Tocci G, Wilkins DM, Liang C, Ceriotti M, Roke S. Electrolytes induce long-range orientational order and free energy changes in the H-bond network of bulk water. Sci Adv 2016; 2:e1501891. [PMID: 27152357 PMCID: PMC4846452 DOI: 10.1126/sciadv.1501891] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 03/06/2016] [Indexed: 05/05/2023]
Abstract
Electrolytes interact with water in many ways: changing dipole orientation, inducing charge transfer, and distorting the hydrogen-bond network in the bulk and at interfaces. Numerous experiments and computations have detected short-range perturbations that extend up to three hydration shells around individual ions. We report a multiscale investigation of the bulk and surface of aqueous electrolyte solutions that extends from the atomic scale (using atomistic modeling) to nanoscopic length scales (using bulk and interfacial femtosecond second harmonic measurements) to the macroscopic scale (using surface tension experiments). Electrolytes induce orientational order at concentrations starting at 10 μM that causes nonspecific changes in the surface tension of dilute electrolyte solutions. Aside from ion-dipole interactions, collective hydrogen-bond interactions are crucial and explain the observed difference of a factor of 6 between light water and heavy water.
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Affiliation(s)
- Yixing Chen
- Laboratory for fundamental BioPhotonics, Institutes of Bioengineering and Materials Science and Engineering, School of Engineering, and Lausanne Centre for Ultrafast Science, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Halil I. Okur
- Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
| | - Nikolaos Gomopoulos
- Laboratory for fundamental BioPhotonics, Institutes of Bioengineering and Materials Science and Engineering, School of Engineering, and Lausanne Centre for Ultrafast Science, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Carlos Macias-Romero
- Laboratory for fundamental BioPhotonics, Institutes of Bioengineering and Materials Science and Engineering, School of Engineering, and Lausanne Centre for Ultrafast Science, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Paul S. Cremer
- Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Poul B. Petersen
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Gabriele Tocci
- Laboratory for fundamental BioPhotonics, Institutes of Bioengineering and Materials Science and Engineering, School of Engineering, and Lausanne Centre for Ultrafast Science, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Laboratory of Computational Science and Modeling, Institute of Materials Science and Engineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - David M. Wilkins
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Chungwen Liang
- Laboratory of Computational Science and Modeling, Institute of Materials Science and Engineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Michele Ceriotti
- Laboratory of Computational Science and Modeling, Institute of Materials Science and Engineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sylvie Roke
- Laboratory for fundamental BioPhotonics, Institutes of Bioengineering and Materials Science and Engineering, School of Engineering, and Lausanne Centre for Ultrafast Science, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Corresponding author. E-mail:
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35
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Poyton MF, Sendecki AM, Cong X, Cremer PS. Cu2+ Binds to Phosphatidylethanolamine and Increases Oxidation in Lipid Membranes. J Am Chem Soc 2016; 138:1584-90. [DOI: 10.1021/jacs.5b11561] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Matthew F. Poyton
- Department
of Chemistry, Penn State University, University Park, Pennsylvania 16801, United States
| | - Anne M. Sendecki
- Department
of Chemistry, Penn State University, University Park, Pennsylvania 16801, United States
| | - Xiao Cong
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Paul S. Cremer
- Department
of Chemistry, Penn State University, University Park, Pennsylvania 16801, United States
- Department
of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania 16801, United States
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36
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Liu C, Huang D, Yang T, Cremer PS. Simultaneous Detection of Multiple Proteins that Bind to the Identical Ligand in Supported Lipid Bilayers. Anal Chem 2015; 87:7163-70. [DOI: 10.1021/acs.analchem.5b00999] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Chunming Liu
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
| | - Da Huang
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
| | - Tinglu Yang
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
- Department
of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Paul S. Cremer
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
- Department
of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
- Department
of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania 16802, United States
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37
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Cong X, Poyton MF, Baxter AJ, Pullanchery S, Cremer PS. Unquenchable Surface Potential Dramatically Enhances Cu(2+) Binding to Phosphatidylserine Lipids. J Am Chem Soc 2015; 137:7785-92. [PMID: 26065920 DOI: 10.1021/jacs.5b03313] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Herein, the apparent equilibrium dissociation constant, K(Dapp), between Cu(2+) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine (POPS), a negatively charged phospholipid, was measured as a function of PS concentrations in supported lipid bilayers (SLBs). The results indicated that K(Dapp) for Cu(2+) binding to PS-containing SLBs was enhanced by a factor of 17,000 from 110 nM to 6.4 pM as the PS density in the membrane was increased from 1.0 to 20 mol %. Although Cu(2+) bound bivalently to POPS at higher PS concentrations, this was not the dominant factor in increasing the binding affinity. Rather, the higher concentration of Cu(2+) within the double layer above the membrane was largely responsible for the tightening. Unlike the binding of other divalent metal ions such as Ca(2+) and Mg(2+) to PS, Cu(2+) binding does not alter the net negative charge on the membrane as the Cu(PS)2 complex forms. As such, the Cu(2+) concentration within the double layer region was greatly amplified relative to its concentration in bulk solution as the PS density was increased. This created a far larger enhancement to the apparent binding affinity than is observed by standard multivalent effects. These findings should help provide an understanding on the extent of Cu(2+)-PS binding in cell membranes, which may be relevant to biological processes such as amyloid-β peptide toxicity and lipid oxidation.
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38
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Abstract
Herein, we use a combination of thermodynamic and spectroscopic measurements to investigate the interactions of Hofmeister anions with a thermoresponsive polymer, poly(N,N-diethylacrylamide) (PDEA). This amide-based polymer does not contain an NH moiety in its chemical structure and, thus, can serve as a model to test if anions bind to amides in the absence of an NH site. The lower critical solution temperature (LCST) of PDEA was measured as a function of the concentration for 11 sodium salts in aqueous solutions, and followed a direct Hofmeister series for the ability of anions to precipitate the polymer. More strongly hydrated anions (CO3(2-), SO4(2-), S2O3(2-), H2PO4(-), F(-), and Cl(-)) linearly decreased the LCST of the polymer with increasing the salt concentration. Weakly hydrated anions (SCN(-), ClO4(-), I(-), NO3(-), and Br(-)) increased the LCST at lower salt concentrations but salted the polymer out at higher salt concentrations. Proton nuclear magnetic resonance (NMR) was used to probe the mechanism of the salting-in effect and showed apparent binding between weakly hydrated anions (SCN(-) and I(-)) and the α protons of the polymer backbone. Additional experiments performed by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy found little change in the amide I band upon the addition of salt, which is consistent with very limited, if any, interactions between the salt ions and the carbonyl moiety of the amide. These results support a molecular mechanism for ion-specific effects on proteins and model amides that does not specifically require an NH group to interact with the anions for the salting-in effect to occur.
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39
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Abstract
We demonstrate a procedure for the separation of enzymes based on their chemotactic response toward an imposed substrate concentration gradient. The separation is observed within a two-inlet, five-outlet microfluidic network, designed to allow mixtures of active (ones that catalyze substrate turnover) and inactive (ones that do not catalyze substrate turnover) enzymes, labeled with different fluorophores, to flow through one of the inlets. Substrate solution prepared in phosphate buffer was introduced through the other inlet of the device at the same flow rate. The steady-state concentration profiles of the enzymes were obtained at specific positions within the outlets of the microchannel using fluorescence microscopy. In the presence of a substrate concentration gradient, active enzyme molecules migrated preferentially toward the substrate channel. The excess migration of the active enzyme molecules was quantified in terms of an enrichment coefficient. Experiments were carried out with different pairs of enzymes. Coupling the physics of laminar flow of liquid and molecular diffusion, multiphysics simulations were carried out to estimate the extent of the chemotactic separation. Our results show that, with appropriate microfluidic arrangement, molecular chemotaxis leads to spontaneous separation of active enzyme molecules from their inactive counterparts of similar charge and size.
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Affiliation(s)
- Krishna Kanti Dey
- Department of Chemistry, ‡Department of Biomedical Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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40
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41
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Liu C, Huang D, Yang T, Cremer PS. Monitoring phosphatidic acid formation in intact phosphatidylcholine bilayers upon phospholipase D catalysis. Anal Chem 2014; 86:1753-9. [PMID: 24456402 PMCID: PMC3983022 DOI: 10.1021/ac403580r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 01/15/2014] [Indexed: 12/25/2022]
Abstract
We have monitored the production of the negatively charged lipid, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidic acid acid (POPA), in supported lipid bilayers via the enzymatic hydrolysis of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (PC), a zwitterionic lipid. Experiments were performed with phospholipase D (PLD) in a Ca(2+) dependent fashion. The strategy for doing this involved using membrane-bound streptavidin as a biomarker for the charge on the membrane. The focusing position of streptavidin in electrophoretic-electroosmotic focusing (EEF) experiments was monitored via a fluorescent tag on this protein. The negative charge increased during these experiments due to the formation of POPA lipids. This caused the focusing position of streptavidin to migrate toward the negatively charged electrode. With the use of a calibration curve, the amount of POPA generated during this assay could be read out from the intact membrane, an objective that has been otherwise difficult to achieve because of the lack of unique chromophores on PA lipids. On the basis of these results, other enzymatic reactions involving the change in membrane charge could also be monitored in a similar way. This would include phosphorylation, dephosphorylation, lipid biosynthesis, and additional phospholipase reactions.
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Affiliation(s)
- Chunming Liu
- Department
of Chemistry, Texas A&M University, 3255 TAMU, College Station, TX 77843, United States
| | - Da Huang
- Department
of Chemistry, Texas A&M University, 3255 TAMU, College Station, TX 77843, United States
| | - Tinglu Yang
- Department
of Chemistry, Texas A&M University, 3255 TAMU, College Station, TX 77843, United States
| | - Paul S. Cremer
- Department
of Chemistry, Texas A&M University, 3255 TAMU, College Station, TX 77843, United States
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Hladílková J, Heyda J, Rembert KB, Okur HI, Kurra Y, Liu WR, Hilty C, Cremer PS, Jungwirth P. Effects of End Group Termination on Salting-Out Constants for Triglycine. J Phys Chem Lett 2013; 4:4069-4073. [PMID: 24466388 PMCID: PMC3898588 DOI: 10.1021/jz4022238] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Salting out constants for triglycine were calculated for a series of Hofmeister salts using molecular dynamics simulations. Three variants of the peptide were considered with both termini capped, just the N-terminus capped, and without capping. The simulations were supported by NMR and FTIR measurements. The data provide strong evidence that earlier experimental values of salting out constants assigned to the fully capped peptide (as previously assumed) should have been assigned to the half-capped peptide instead. Therefore, these values cannot be used to directly establish Hofmeister ordering of ions at the peptide backbone, since they are strongly influenced by interactions of the ions with the negatively charged C-terminus.
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Affiliation(s)
- Jana Hladílková
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610, Prague 6, Czech Republic
| | - Jan Heyda
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, 14109 Berlin, Germany
| | - Kelvin B. Rembert
- Chemistry Department, Penn State University, University Park, PA 16802, USA
| | - Halil I. Okur
- Chemistry Department, Penn State University, University Park, PA 16802, USA
| | - Yadagiri Kurra
- Chemistry Department, Texas A&M University, College Station, TX 77843
| | - Wenshe R. Liu
- Chemistry Department, Texas A&M University, College Station, TX 77843
| | - Christian Hilty
- Chemistry Department, Texas A&M University, College Station, TX 77843
| | - Paul S. Cremer
- Chemistry Department, Penn State University, University Park, PA 16802, USA
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610, Prague 6, Czech Republic
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43
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Abstract
While electrophoresis in lipid bilayers has been performed since the 1970s, the technique has until now been unable to accurately measure the charge on lipids and proteins within the membrane based on drift velocity measurements. Part of the problem is caused by the use of the Einstein-Smoluchowski equation to estimate the electrophoretic mobility of such species. The source of the error arises from the fact that a lipid headgroup is typically smaller than the Debye length of the adjacent aqueous solution in most electrophoresis experiments. Instead, the Henry equation can more accurately predict the electrophoretic mobility at sufficient ionic strength. This was done for three dye-labeled lipids with different sized head groups and a charge on each lipid of -1. Also, the charge was measured as a function of pH for two titratable lipids that were fluorescently labeled. Finally, it was shown that the Henry equation also has difficulties measuring the correct lipid charge at salt concentrations below 5 mM, where electroosmotic forces are more significant.
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Affiliation(s)
- Matthew F Poyton
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Penn State University , State College, Pennsylvania 16802, United States
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Abstract
Herein, we utilized a label-free sensing platform based on pH modulation to detect the interactions between tetracaine, a positively charged small molecule used as a local anesthetic, and planar supported lipid bilayers (SLBs). The SLBs were patterned inside a flow cell, allowing for various concentrations of tetracaine to be introduced over the surface in a buffer solution. Studies with membranes containing POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) yielded an equilibrium dissociation constant value of Kd = 180 ± 47 μm for this small molecule-membrane interaction. Adding cholesterol to the SLBs decreased the affinity between tetracaine and the bilayers, while this interaction tightened when POPE (1-hexadecanoyl-2-(9-Z-octadecenoyl)-sn-glycero-3-phosphoethanolamine) was added. Studies were also conducted with three negatively charged membrane lipids, POPG (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt)), POPS (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine (sodium salt)), and ganglioside GM1. All three measurements gave rise to a similar tightening of the apparent Kd value compared with pure POPC membranes. The lack of chemical specificity with the identity of the negatively charged lipid indicated that the tightening was largely electrostatic. Through a direct comparison with ITC measurements, it was found that the pH modulation sensor platform offers a facile, inexpensive, highly sensitive, and rapid method for the detection of interactions between putative drug candidates and lipid bilayers. As such, this technique may potentially be exploited as a screen for drug development and analysis.
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Affiliation(s)
- Da Huang
- Department of Chemistry and §Department of Biochemistry and Molecular Biology, Penn State University , University Park, PA 16802
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45
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Paterová J, Rembert KB, Heyda J, Kurra Y, Okur HI, Liu WR, Hilty C, Cremer PS, Jungwirth P. Reversal of the hofmeister series: specific ion effects on peptides. J Phys Chem B 2013; 117:8150-8. [PMID: 23768138 DOI: 10.1021/jp405683s] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ion-specific effects on salting-in and salting-out of proteins, protein denaturation, as well as enzymatic activity are typically rationalized in terms of the Hofmeister series. Here, we demonstrate by means of NMR spectroscopy and molecular dynamics simulations that the traditional explanation of the Hofmeister ordering of ions in terms of their bulk hydration properties is inadequate. Using triglycine as a model system, we show that the Hofmeister series for anions changes from a direct to a reversed series upon uncapping the N-terminus. Weakly hydrated anions, such as iodide and thiocyanate, interact with the peptide bond, while strongly hydrated anions like sulfate are repelled from it. In contrast, reversed order in interactions of anions is observed at the positively charged, uncapped N-terminus, and by analogy, this should also be the case at side chains of positively charged amino acids. These results demonstrate that the specific chemical and physical properties of peptides and proteins play a fundamental role in ion-specific effects. The present study thus provides a molecular rationalization of Hofmeister ordering for the anions. It also provides a route for tuning these interactions by titration or mutation of basic amino acid residues on the protein surface.
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Affiliation(s)
- Jana Paterová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
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Pace HP, Sherrod SD, Monson CF, Russell DH, Cremer PS. Coupling supported lipid bilayer electrophoresis with matrix-assisted laser desorption/ionization-mass spectrometry imaging. Anal Chem 2013; 85:6047-52. [PMID: 23731179 PMCID: PMC3717335 DOI: 10.1021/ac4008804] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Herein, we describe a new analytical platform utilizing advances in heterogeneous supported lipid bilayer (SLB) electrophoresis and matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) imaging. This platform allowed for the separation and visualization of both charged and neutral lipid membrane components without the need for extrinsic labels. A heterogeneous SLB was created using vesicles containing monosialoganglioside GM1, disialoganglioside GD1b, POPC, as well as the ortho and para isomers of Texas Red-DHPE. These components were then separated electrophoretically into five resolved bands. This represents the most complex separation by SLB electrophoresis performed to date. The SLB samples were flash frozen in liquid ethane and dried under vacuum before imaging with MALDI-MS. Fluorescence microscopy was employed to confirm the position of the Texas Red labeled lipids, which agreed well with the MALDI-MS imaging results. These results clearly demonstrate this platform's ability to isolate and identify nonlabeled membrane components within an SLB.
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Affiliation(s)
- Hudson P. Pace
- Department of Chemistry, Texas A&M University, College Station, TX 77843
| | - Stacy D. Sherrod
- Department of Chemistry, Texas A&M University, College Station, TX 77843
| | | | - David H. Russell
- Department of Chemistry, Texas A&M University, College Station, TX 77843
| | - Paul S. Cremer
- Department of Chemistry, Texas A&M University, College Station, TX 77843
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Abstract
Herein, we describe a novel colloidal lithographic strategy for the stepwise patterning of planar substrates with numerous complex and unique designs. In conjunction with colloidal self-assembly, imprint molding, and capillary force lithography, reactive ion etching was used to create complex libraries of nanoscale features. This combinatorial strategy affords the ability to develop an exponentially increasing number of two-dimensional nanoscale patterns with each sequential step in the process. Specifically, dots, triangles, circles, and lines could be assembled on the surface separately and in combination with each other. Numerous architectures are obtained for the first time with high uniformity and reproducibility. These hexagonal arrays were made from polystyrene and gold features, whereby each surface element could be tuned from the micrometer size scale down to line widths of ~35 nm. The patterned area could be 1 cm(2) or even larger. The techniques described herein can be combined with further steps to make even larger libraries. Moreover, these polymer and metal features may prove useful in optical, sensing, and electronic applications.
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Affiliation(s)
- Zhi Zhao
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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48
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Affiliation(s)
- Halil I. Okur
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Jaibir Kherb
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Paul S. Cremer
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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49
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Huang D, Robison AD, Liu Y, Cremer PS. Monitoring protein–small molecule interactions by local pH modulation. Biosens Bioelectron 2012; 38:74-8. [DOI: 10.1016/j.bios.2012.05.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 04/30/2012] [Accepted: 05/02/2012] [Indexed: 11/25/2022]
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Sagle LB, Ruvuna LK, Bingham JM, Liu C, Cremer PS, Van Duyne RP. Single plasmonic nanoparticle tracking studies of solid supported bilayers with ganglioside lipids. J Am Chem Soc 2012; 134:15832-9. [PMID: 22938041 PMCID: PMC3526348 DOI: 10.1021/ja3054095] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Single-particle tracking experiments were carried out with gold nanoparticle-labeled solid supported lipid bilayers (SLBs) containing increasing concentrations of ganglioside (GM(1)). The negatively charged nanoparticles electrostatically associate with a small percentage of positively charged lipids (ethyl phosphatidylcholine) in the bilayers. The samples containing no GM(1) show random diffusion in 92% of the particles examined with a diffusion constant of 4.3(±4.5) × 10(-9) cm(2)/s. In contrast, samples containing 14% GM(1) showed a mixture of particles displaying both random and confined diffusion, with the majority of particles, 62%, showing confined diffusion. Control experiments support the notion that the nanoparticles are not associating with the GM(1) moieties but instead most likely confined to regions in between the GM(1) clusters. Analysis of the root-mean-squared displacement plots for all of the data reveals decreasing trends in the confined diffusion constant and diameter of the confining region versus increasing GM(1) concentration. In addition, a linearly decreasing trend is observed for the percentage of randomly diffusing particles versus GM(1) concentration, which offers a simple, direct way to measure the percolation threshold for this system, which has not previously been measured. The percolation threshold is found to be 22% GM(1) and the confining diameter at the percolation threshold only ∼50 nm.
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Affiliation(s)
- Laura B. Sagle
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, United Sates
| | - Laura K. Ruvuna
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, United Sates
| | - Julia M. Bingham
- Department of Chemistry, Saint Xavier University, 3700 West 103 Street, Chicago, IL 60655, United Sates
| | - Chunming Liu
- Department of Chemistry, Texas A&M University, 3255 TAMU College Station, TX 77843, United Sates
| | - Paul S. Cremer
- Department of Chemistry, Texas A&M University, 3255 TAMU College Station, TX 77843, United Sates
| | - Richard P. Van Duyne
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, United Sates
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