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Acar M, Tatini D, Budroni MA, Ninham BW, Rustici M, Rossi F, Lo Nostro P. Specific anion effects on urease activity: A Hofmeister study. Colloids Surf B Biointerfaces 2024; 236:113789. [PMID: 38367291 DOI: 10.1016/j.colsurfb.2024.113789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/24/2024] [Accepted: 02/04/2024] [Indexed: 02/19/2024]
Abstract
The effects of a range of electrolytes on the hydrolysis of urea by the enzyme urease is explored. The autocatalytic behavior of urease in unbuffered solutions and its pH clock reactions are studied. The concentration dependence of the experimental variables is analyzed in terms of specific ion-enzyme interactions and hydration. The results offer insights into the molecular mechanisms of the enzyme, and on the nature of its interactions with the electrolytes. We found that urease can tolerate mild electrolytes in its environment, while it is strongly inhibited by both strong kosmotropic and strong chaotropic anions. This study may cast light on an alternative therapy for Helicobacter pylori infections and contribute to the design of innovative materials and provide new approaches for the modulation of the enzymatic activity.
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Affiliation(s)
- Mert Acar
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, Sesto Fiorentino, Firenze 50019, Italy
| | - Duccio Tatini
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, Sesto Fiorentino, Firenze 50019, Italy
| | - Marcello A Budroni
- Department of Chemistry and Pharmacy, University of Sassari, Sassari 07100, Italy
| | - Barry W Ninham
- Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia
| | - Mauro Rustici
- Department of Chemistry and Pharmacy, University of Sassari, Sassari 07100, Italy
| | - Federico Rossi
- Department of Earth, Environmental and Physical Sciences-DEEP Sciences, University of Siena, Italy
| | - Pierandrea Lo Nostro
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, Sesto Fiorentino, Firenze 50019, Italy.
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2
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Sorfleet JT, Shin JW. Polarimetry study of the intrinsic rotation of (1R,4R)-(+)-camphor in organic solvents. Chem Phys 2023. [DOI: 10.1016/j.chemphys.2023.111904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
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3
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Acharyya A, Mukherjee D, Gai F. Assessing the Effect of Hofmeister Anions on the Hydrogen-Bonding Strength of Water via Nitrile Stretching Frequency Shift. J Phys Chem B 2020; 124:11783-11792. [PMID: 33346656 DOI: 10.1021/acs.jpcb.0c06299] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The temperature dependence of the peak frequency (νmax) of the C≡N stretching vibrational spectrum of a hydrogen-bonded C≡N species is known to be a qualitative measure of its hydrogen-bonding strength. Herein, we show that within a two-state framework, this dependence can be analyzed in a more quantitative manner to yield the enthalpy and entropy changes (ΔHHB and ΔSHB) for the corresponding hydrogen-bonding interactions. Using this method, we examine the effect of ten common anions on the strength of the hydrogen-bond(s) formed between water and the C≡N group of an unnatural amino acid, p-cyanophenylalanine (PheCN). We find that based on the ΔHHB values, these anions can be arranged in the following order: HPO42- > OAc- > F- > SO42- ≈ Cl- ≈ (H2O) ≈ ClO4- ≈ NO3- > Br- > SCN- ≈ I-, which differs from the corresponding Hofmeister series. Because PheCN has a relatively small size, the finding that anions having very different charge densities (e.g., SO42- and ClO4-) act similarly suggests that this ranking order is likely the result of specific ion effects. Since proteins contain different backbone and side-chain units, our results highlight the need to assess their individual contributions toward the overall Hofmeister effect in order to achieve a microscopic understanding of how ions affect the physical and chemical properties of such macromolecules. In addition, the analytical method described in the present study is applicable for analyzing the spectral evolution of any vibrational spectra composed of two highly overlapping bands.
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Affiliation(s)
- Arusha Acharyya
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Debopreeti Mukherjee
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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4
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Richards DS, Trobaugh KL, Hajek-Herrera J, Price CL, Sheldon CS, Davies JF, Davis RD. Ion-molecule interactions enable unexpected phase transitions in organic-inorganic aerosol. SCIENCE ADVANCES 2020; 6:6/47/eabb5643. [PMID: 33208357 PMCID: PMC7673807 DOI: 10.1126/sciadv.abb5643] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 10/07/2020] [Indexed: 05/17/2023]
Abstract
Atmospheric aerosol particles are commonly complex, aqueous organic-inorganic mixtures, and accurately predicting the properties of these particles is essential for air quality and climate projections. The prevailing assumption is that aqueous organic-inorganic aerosols exist predominately with liquid properties and that the hygroscopic inorganic fraction lowers aerosol viscosity relative to the organic fraction alone. Here, in contrast to those assumptions, we demonstrate that increasing inorganic fraction can increase aerosol viscosity (relative to predictions) and enable a humidity-dependent gel phase transition through cooperative ion-molecule interactions that give rise to long-range networks of atmospherically relevant low-mass oxygenated organic molecules (180 to 310 Da) and divalent inorganic ions. This supramolecular, ion-molecule effect can drastically influence the phase and physical properties of organic-inorganic aerosol and suggests that aerosol may be (semi)solid under more conditions than currently predicted. These observations, thus, have implications for air quality and climate that are not fully represented in atmospheric models.
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Affiliation(s)
- David S Richards
- Department of Chemistry, Trinity University, 1 Trinity Place, San Antonio, TX 78212, USA
| | - Kristin L Trobaugh
- Department of Chemistry, Trinity University, 1 Trinity Place, San Antonio, TX 78212, USA
| | - Josefina Hajek-Herrera
- Department of Chemistry, Trinity University, 1 Trinity Place, San Antonio, TX 78212, USA
| | - Chelsea L Price
- Department of Chemistry, University of California-Riverside, Riverside, CA 92521, USA
| | - Craig S Sheldon
- Department of Chemistry, University of California-Riverside, Riverside, CA 92521, USA
| | - James F Davies
- Department of Chemistry, University of California-Riverside, Riverside, CA 92521, USA
| | - Ryan D Davis
- Department of Chemistry, Trinity University, 1 Trinity Place, San Antonio, TX 78212, USA.
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5
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Góngora-García OR, Aca-Aca G, Baz-Rodríguez SA. Mass transfer in aerated culture media combining mixed electrolytes and glucose. Bioprocess Biosyst Eng 2020; 44:81-92. [PMID: 32840678 DOI: 10.1007/s00449-020-02424-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 08/07/2020] [Indexed: 11/28/2022]
Abstract
The combined effects of mixed electrolyte species and glucose on oxygen transfer were studied in a bubble column with aqueous solutions. Of particular interest was the presence of electrolytes containing ions which are prone to present solute-solute interactions or to crystallize. Without and at low concentration of glucose (≤ 5 g/L), the increasing concentration of electrolytes (nominal ionic strength: 0-0.43 M), up to a critical value, enhanced the volumetric mass transfer coefficient (kLa) and the availability of specific interfacial area (a), due to the inhibition of bubble coalescence. As the glucose concentration increased (10-40 g/L), the enhancing effects of electrolytes were gradually lost. The glucose interacted with electrolytes, reducing their ability to inhibit coalescence and to enhance the kLa. Salt crystallization occurred independently of the addition of glucose; however, it did not have significant effect on mass transfer. Finally, the changes in physicochemical properties were highly collinear with composition variables.
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Affiliation(s)
- Oscar R Góngora-García
- Facultad de Ingenieria Quimica, Universidad Autonoma de Yucatan, Campus de Ciencias Exactas e Ingenierias, 97203, Mérida, YUC, Mexico
| | - Gloria Aca-Aca
- Facultad de Ingenieria Quimica, Universidad Autonoma de Yucatan, Campus de Ciencias Exactas e Ingenierias, 97203, Mérida, YUC, Mexico
| | - Sergio A Baz-Rodríguez
- Facultad de Ingenieria Quimica, Universidad Autonoma de Yucatan, Campus de Ciencias Exactas e Ingenierias, 97203, Mérida, YUC, Mexico.
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6
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Yan X, Chu Y, Liu B, Ru G, Di Y, Feng J. Dynamic mechanism of halide salts on the phase transition of protein models, poly(N-isopropylacrylamide) and poly(N,N-diethylacrylamide). Phys Chem Chem Phys 2020; 22:12644-12650. [PMID: 32458929 DOI: 10.1039/d0cp01366h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effects of salts on protein systems are not yet fully understood. We investigated the ionic dynamics of three halide salts (NaI, NaBr, and NaCl) with two protein models, namely poly(N-isopropylacrylamide) (PNIPAM) and poly(N,N-diethylacrylamide) (PDEA), using multinuclear NMR, dispersion corrected density functional theory (DFT-D) calculations and dynamic light scattering (DLS) methods. The variation in ionic line-widths and chemical shifts induced by the polymers clearly illustrates that anions rather than cations interact directly with the polymers. From the variable temperature measurements of the NMR transverse relaxation rates of anions, which characterize the polymer-anion interaction intensities, the evolution behaviors of Cl-/Br-/I- during phase transitions are similar in each polymer system but differ between the two polymer systems. The NMR transverse relaxation rates of anions change synchronously with the phase transition of PNIPAM upon heating, but they drop rapidly and vanish about 3-4.5 °C before the phase transition of PDEA. By combining the DFT-D and DLS data, the relaxation results imply that anions escape from the interacting sites with PDEA prior to full polymer dehydration or collapse, which can be attributed to the lack of anion-NH interactions. The different dynamic evolutions of the anions in the PNIPAM and PDEA systems give us an important clue for understanding the micro-mechanism of protein folding in a complex salt aqueous solvent.
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Affiliation(s)
- Xiaoshuang Yan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China.
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7
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Giuffrida S, Cottone G, Cordone L. The water association band as a marker of hydrogen bonds in trehalose amorphous matrices. Phys Chem Chem Phys 2017; 19:4251-4265. [DOI: 10.1039/c6cp06848k] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The water association band is a suitable marker of residual water behavior in bioprotective trehalose matrices.
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Affiliation(s)
- Sergio Giuffrida
- Dipartimento di Fisica e Chimica
- Università degli Studi di Palermo
- Palermo
- Italy
| | - Grazia Cottone
- Dipartimento di Fisica e Chimica
- Università degli Studi di Palermo
- Palermo
- Italy
- School of Physics
| | - Lorenzo Cordone
- Dipartimento di Fisica e Chimica
- Università degli Studi di Palermo
- Palermo
- Italy
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8
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Dai P, Zhang C, Welborn M, Shepherd J, Zhu T, Van Voorhis T, Pentelute BL. Salt Effect Accelerates Site-Selective Cysteine Bioconjugation. ACS CENTRAL SCIENCE 2016; 2:637-646. [PMID: 27725962 PMCID: PMC5043432 DOI: 10.1021/acscentsci.6b00180] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Indexed: 05/16/2023]
Abstract
Highly efficient and selective chemical reactions are desired. For small molecule chemistry, the reaction rate can be varied by changing the concentration, temperature, and solvent used. In contrast for large biomolecules, the reaction rate is difficult to modify by adjusting these variables because stringent biocompatible reaction conditions are required. Here we show that adding salts can change the rate constant over 4 orders of magnitude for an arylation bioconjugation reaction between a cysteine residue within a four-residue sequence (π-clamp) and a perfluoroaryl electrophile. Biocompatible ammonium sulfate significantly enhances the reaction rate without influencing the site-specificity of π-clamp mediated arylation, enabling the fast synthesis of two site-specific antibody-drug conjugates that selectively kill HER2-positive breast cancer cells. Computational and structure-reactivity studies indicate that salts may tune the reaction rate through modulating the interactions between the π-clamp hydrophobic side chains and the electrophile. On the basis of this understanding, the salt effect is extended to other bioconjugation chemistry, and a new regioselective alkylation reaction at π-clamp cysteine is developed.
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9
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Ferreira LA, Loureiro JA, Gomes J, Uversky VN, Madeira PP, Zaslavsky BY. Why physicochemical properties of aqueous solutions of various compounds are linearly interrelated. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2016.05.068] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Interrelationship between partition behavior of organic compounds and proteins in aqueous dextran-polyethylene glycol and polyethylene glycol-sodium sulfate two-phase systems. J Chromatogr A 2016; 1443:21-5. [DOI: 10.1016/j.chroma.2016.03.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/14/2016] [Accepted: 03/14/2016] [Indexed: 01/01/2023]
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11
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Madeira PP, Bessa A, Loureiro JA, Álvares-Ribeiro L, Rodrigues AE, Zaslavsky BY. Cooperativity between various types of polar solute–solvent interactions in aqueous media. J Chromatogr A 2015; 1408:108-17. [DOI: 10.1016/j.chroma.2015.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 06/29/2015] [Accepted: 07/01/2015] [Indexed: 01/01/2023]
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12
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Responses of proteins to different ionic environment are linearly interrelated. J Chromatogr A 2015; 1387:32-41. [DOI: 10.1016/j.chroma.2015.02.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/30/2015] [Accepted: 02/03/2015] [Indexed: 01/03/2023]
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13
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Secondary Metabolites of the Zoanthid-Derived Fungus Trichoderma sp. TA26-28 Collected from the South China Sea. Chem Nat Compd 2014. [DOI: 10.1007/s10600-014-1134-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Ferreira LA, Chervenak A, Placko S, Kestranek A, Madeira PP, Zaslavsky BY. Responses of polar organic compounds to different ionic environments in aqueous media are interrelated. Phys Chem Chem Phys 2014; 16:23347-54. [DOI: 10.1039/c4cp02084g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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15
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Zhang R, Zhuang W. Cation effect in the ionic solution optical Kerr effect measurements: A simulation study. J Chem Phys 2014; 140:054507. [PMID: 24511952 DOI: 10.1063/1.4863696] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ruiting Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, People's Republic of China
| | - Wei Zhuang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, People's Republic of China
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16
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Perisic N, Afseth NK, Ofstad R, Narum B, Kohler A. Characterizing salt substitution in beef meat processing by vibrational spectroscopy and sensory analysis. Meat Sci 2013; 95:576-85. [DOI: 10.1016/j.meatsci.2013.05.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 03/05/2013] [Accepted: 05/30/2013] [Indexed: 10/26/2022]
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17
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Airoldi M, Gennaro G, Giomini M, Giuliani AM, Giustini M. Effect of the alkaline cations on the stability of the model polynucleotide poly(dG-dC)·poly(dG-dC). J Biomol Struct Dyn 2012; 29:585-94. [PMID: 22066543 DOI: 10.1080/07391102.2011.10507407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
When the model polynucleotide poly(dG-dC)∙poly(dG-dC) [polyGC] is titrated with a strong acid (HCl) in unbuffered aqueous solutions containing the chlorides of the alkali metals in the concentration range 0.010 M-0.600 M, two transitions in the absorbance vs. pH plots are evidenced, characterized by the constants pK(a(₁)) and pK(a(₂)). The limiting values at infinite saline concentrations of these two constants, namely pK(∞)(a(₁)) and pK(∞)(a(₂)) obtained making use of the "one site saturation constant" equation or, in turn, of the double logarithmic plot: pK(a) vs. log([salt]⁻¹), exhibit a clear dependence on the nature of the cations. The effects of the different alkali cations on the pK(∞)(a) values follow the Hofmeister series. In fact, the pK(∞)(a(₁)) and the pK(∞)(a(₂)) values are smaller for Li+ and Na+ than for Rb+ and Cs+, with K+ at the border between the two, showing that the transitions require higher concentrations of protons to occur in the presence of high concentrations of the cosmotropic ions.
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Affiliation(s)
- Marta Airoldi
- Dipartimento di Chimica "S. Cannizzaro", Universita di Palermo, Viale delle Scienze, Pad. 17, 90128 Palermo, Italy
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18
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Kim H, Lee H, Lee G, Kim H, Cho M. Hofmeister anionic effects on hydration electric fields around water and peptide. J Chem Phys 2012; 136:124501. [DOI: 10.1063/1.3694036] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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19
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Lo Nostro P, Ninham BW. Hofmeister phenomena: an update on ion specificity in biology. Chem Rev 2012; 112:2286-322. [PMID: 22251403 DOI: 10.1021/cr200271j] [Citation(s) in RCA: 675] [Impact Index Per Article: 56.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Pierandrea Lo Nostro
- Department of Chemistry and CSGI, University of Florence, 50019 Sesto Fiorentino (Firenze), Italy.
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20
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Kim H, Park S, Cho M. Rotational dynamics of thiocyanate ions in highly concentrated aqueous solutions. Phys Chem Chem Phys 2012; 14:6233-40. [DOI: 10.1039/c2cp23749k] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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21
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Airoldi M, Gennaro G, Giomini M, Giuliani AM, Giustini M. Effect of the Alkaline Cations on the Stability of the Model Polynucleotide Poly(dG-dC)·Poly(dG-dC). J Biomol Struct Dyn 2011. [DOI: 10.1080/07391102.2011.10507395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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22
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Lee KK, Park KH, Kwon D, Choi JH, Son H, Park S, Cho M. Ion-pairing dynamics of Li+ and SCN− in dimethylformamide solution: Chemical exchange two-dimensional infrared spectroscopy. J Chem Phys 2011; 134:064506. [DOI: 10.1063/1.3552961] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Park K, Choi SR, Choi J, Park S, Cho M. Real‐Time Probing of Ion Pairing Dynamics with 2DIR Spectroscopy. Chemphyschem 2010; 11:3632-7. [DOI: 10.1002/cphc.201000595] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Kwang‐Hee Park
- Department of Chemistry, Korea University, Seoul 136‐701 (Korea), Fax: (+82) 2‐3290‐3121
| | - Seung Ryul Choi
- Department of Chemistry, Korea University, Seoul 136‐701 (Korea), Fax: (+82) 2‐3290‐3121
| | - Jun‐Ho Choi
- Department of Chemistry, Korea University, Seoul 136‐701 (Korea), Fax: (+82) 2‐3290‐3121
| | - Sungnam Park
- Department of Chemistry, Korea University, Seoul 136‐701 (Korea), Fax: (+82) 2‐3290‐3121
- Multidimensional Spectroscopy Laboratory, Korea Basic Science Institute, Seoul 136‐713 (Korea)
| | - Minhaeng Cho
- Department of Chemistry, Korea University, Seoul 136‐701 (Korea), Fax: (+82) 2‐3290‐3121
- Multidimensional Spectroscopy Laboratory, Korea Basic Science Institute, Seoul 136‐713 (Korea)
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Chen X, Flores SC, Lim SM, Zhang Y, Yang T, Kherb J, Cremer PS. Specific anion effects on water structure adjacent to protein monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:16447-16454. [PMID: 20560589 DOI: 10.1021/la1015862] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Vibrational sum frequency spectroscopy (VSFS) was used to explore specific ion effects on interfacial water structure adjacent to a bovine serum albumin (BSA) monolayer adsorbed at the air/water interface. The subphase conditions were varied by the use of six different sodium salts and four different pH values. At pH 2 and 3, the protein layer was positively charged and it was found that the most chaotropic anions caused the greatest attenuation of water structure. The order of the salts followed an inverse Hofmeister series. On the other hand, when the protein layer was near its isoelectric point (pH 5), the most chaotropic anions caused the greatest increase in water structure, although the effect was weak. In this case, a direct Hofmeister series was obeyed. Finally, virtually no effect was observed when the protein layer was negatively charged with a subphase pH of 9. For comparison, similar experiments were run with positively charged, negatively charged, and zwitterionic surfactant monolayers. These experiments gave rise to nearly the identical results as the protein monolayer which suggested that specific anion effects are dominated by the charge state of the interfacial layer rather than its detailed chemical structure. In a final set of experiments, salt effects were examined with a monolayer made from an elastin-like polypeptide (ELP). The peptide consisted of 120 pentameric repeats of the sequence Val-Pro-Gly-Val-Gly. Data from this net neutral biopolymer followed a very weak, but direct Hofmeister series. This suggested that direct anion binding to the amide groups in the backbone of a polypeptide is quite weak in agreement with the BSA data. The results from the variously charged protein, surfactant, and polymer monolayers were compared with a modified Gouy-Chapman-Stern model. The agreement with this simple model was quite good.
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Affiliation(s)
- Xin Chen
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA
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25
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Henry CL, Craig VSJ. Inhibition of bubble coalescence by osmolytes: sucrose, other sugars, and urea. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:11406-11412. [PMID: 19572516 DOI: 10.1021/la9015355] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report on bubble coalescence inhibition by non-surface-active, nonelectrolytes urea and sucrose, and other small sugars, in aqueous solution. Urea has no effect on bubble stability up to high concentrations>1 M, while sucrose inhibits coalescence in the range 0.01-0.3 M, similar to inhibiting electrolytes. Urea and sucrose both increase bubble coalescence inhibition in inhibiting and noninhibiting electrolytes in a cooperative manner, but urea decreases the efficacy of sucrose in mixed solutions. Several mono- and disaccharides also inhibit bubble coalescence at approximately 0.1 M, and the sugars vary in effectiveness. Disaccharides are more effective than the sum of their individual monosaccharide constituents, and sugars with very similar structures (for instance, diastereomers galactose and mannose) can show large differences in coalescence inhibition and hence thin film stability. We conclude that solute charge is not required for bubble coalescence inhibition, which indicates that the mechanism is not one of electrostatic surface repulsion and instead an effect on dynamic film thinning other than Gibbs-Marangoni elasticity is implicated. Solute structure is important in determining coalescence.
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Affiliation(s)
- Christine L Henry
- Department of Applied Maths, Research School of Physics, The Australian National University, Canberra ACT 0200, Australia
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26
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Xu L, Li X, Yuan L, Zhai M, Peng J, Li J. Specific F− binding to phenyl ring of aromatic polymers. J Fluor Chem 2009. [DOI: 10.1016/j.jfluchem.2009.07.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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27
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Wang W, Wang Y, Tao H, Peng X, Liu P, Zhu W. Cerebrosides of the halotolerant fungus Alternaria raphani isolated from a sea salt field. JOURNAL OF NATURAL PRODUCTS 2009; 72:1695-1698. [PMID: 19685913 DOI: 10.1021/np9002299] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In order to search for structurally novel and bioactive natural compounds from marine-derived fungi, a halotolerant fungal strain (THW-18) identified as Alternaria raphani was isolated from sediment collected in the Hongdao sea salt field. From the ethyl acetate extract of Alternaria raphani, three new cerebrosides, alternarosides A-C (1-3), and a new diketopiperazine alkaloid, alternarosin A (4), together with 15 known compounds were isolated and identified by spectroscopic and chemical methods, as well as X-ray crystal diffraction analysis. Compounds 1-4 showed weak antibacterial activity against Escherichia coli, Bacillus subtilis, and Candida albicans with MIC values ranging from 70 to 400 muM.
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Affiliation(s)
- Wenliang Wang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, People's Republic of China
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Kundrat MD, Autschbach J. Modeling of the Chiroptical Response of Chiral Amino Acids in Solution Using Explicit Solvation and Molecular Dynamics. J Chem Theory Comput 2009; 5:1051-60. [DOI: 10.1021/ct8005216] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Matthew D. Kundrat
- Department of Chemistry, 312 Natural Sciences Complex, The State University of New York at Buffalo, Buffalo, New York 14260-3000
| | - Jochen Autschbach
- Department of Chemistry, 312 Natural Sciences Complex, The State University of New York at Buffalo, Buffalo, New York 14260-3000
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Weckström K, Papageorgiou AC. Lower consolute boundaries of the nonionic surfactant C8E5 in aqueous alkali halide solutions: An approach to reproduce the effects of alkali halides on the cloud-point temperature. J Colloid Interface Sci 2007; 310:151-62. [PMID: 17306288 DOI: 10.1016/j.jcis.2007.01.045] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2006] [Revised: 01/14/2007] [Accepted: 01/17/2007] [Indexed: 12/01/2022]
Abstract
In the temperature-composition phase diagram of the nonionic surfactant n-octyl-hydroxypenta(oxyethylene), C(8)E(5), there are three principal curves; the one for the critical micelle concentration (cmc), the one delineating the existence of the hexagonal phase, and then the lower consolute boundary (lcb). In this work it is clarified how the presence of the alkali halides NaF, LiCl, NaCl, NaBr and NaI in the aqueous solutions, up to high molalities, change the lcb temperature-position and shape. The lcbs are obtained from measurements of cloud-point temperatures. Rather marked anion-controlled shifts are observed in the boundary temperature-position, and the order of the anions is in accordance with the prediction of the Hofmeister series. Also the shape of the boundary is affected in an anion-specific way, so that the largest changes are found with the strongest salting-out agent. The separation point varies in distinctly non-linear manners with the molality of the studied alkali halides. An approach is presented that can reproduce the effects of the alkali halides on the cloud-point temperature of C(8)E(5) and a poly(ethylene oxide) polymer, at low amounts of the macroentities. In this approach use is made of the known behaviour of the electrolytes at the air/water surface and the virial expansion, to account for the initial salting-out/-in effect and the variation of the effect with electrolyte molality.
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Affiliation(s)
- Kristian Weckström
- Turku Centre for Biotechnology, University of Turku and Abo Akademi University, P.O. Box 123, FIN-20521 Turku, Finland.
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Zhang Y, Furyk S, Sagle LB, Cho Y, Bergbreiter DE, Cremer PS. Effects of Hofmeister Anions on the LCST of PNIPAM as a Function of Molecular Weight. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2007; 111:8916-8924. [PMID: 18820735 PMCID: PMC2553222 DOI: 10.1021/jp0690603] [Citation(s) in RCA: 283] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The effect of a series of sodium salts on the lower critical solution temperature (LCST) of poly(N-isopropylacrylamide), PNIPAM, was investigated as a function of molecular weight and polymer concentration with a temperature gradient microfluidic device under a dark-field microscope. In solutions containing sufficient concentrations of kosmotropic anions, the phase transition of PNIPAM was resolved into two separate steps for higher molecular weight samples. The first step of this two step transition was found to be sensitive to the polymer's molecular weight and solution concentration, while the second step was not. Moreover, the binding of chaotropic anions to the polymer was also influenced by molecular weight. Both sets of results could be explained by the formation of intramolecular and intermolecular hydrogen-bonding between polymer chains. By contrast, the hydrophobic hydration of the isopropyl moieties and polymer backbone was found to be unaffected by either the polymer's molecular weight or solution concentration.
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Lo Nostro P, Ninham BW, Milani S, Lo Nostro A, Pesavento G, Baglioni P. Hofmeister effects in supramolecular and biological systems. Biophys Chem 2006; 124:208-13. [PMID: 16678961 DOI: 10.1016/j.bpc.2006.04.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 04/14/2006] [Accepted: 04/14/2006] [Indexed: 11/19/2022]
Abstract
Specific ion effects, representative of near-universal Hofmeister phenomena, are illustrated in three different systems. These are the formation of supramolecular assemblies from cyclodextrins, the optical rotation of L-serine, and the growth rate of two kinds of microorganisms (Staphylococcus aureus and Pseudomonas aeruginosa). The strong specific ion effects can be correlated with the anion polarizabilities and related physico-chemical parameters. The results show the relevance of dispersion (non-electrostatic) forces in these phenomena.
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Affiliation(s)
- Pierandrea Lo Nostro
- Department of Chemistry and CSGI, University of Florence, 50019 Sesto Fiorentino (Firenze), Italy.
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